<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2025 Workiva-->
<!--r:c4162aed-1e97-4acf-9a68-d88154d9dedb,g:5aa1665a-14ce-4c8e-bc98-d60964e49e8d-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.unfi.com/role/CONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="simple" xlink:href="unfi-20250802.xsd#CONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/CONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_21b9c20a-b27f-4653-86aa-6c8473dcc133" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_c8f0a3b0-05bb-485e-9565-e50848c29ae1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_21b9c20a-b27f-4653-86aa-6c8473dcc133" xlink:to="loc_us-gaap_StatementTable_c8f0a3b0-05bb-485e-9565-e50848c29ae1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_b80e4c36-fabd-43d4-816c-c63bda161506" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c8f0a3b0-05bb-485e-9565-e50848c29ae1" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_b80e4c36-fabd-43d4-816c-c63bda161506" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_b80e4c36-fabd-43d4-816c-c63bda161506_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_b80e4c36-fabd-43d4-816c-c63bda161506" xlink:to="loc_us-gaap_EquityComponentDomain_b80e4c36-fabd-43d4-816c-c63bda161506_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_6d0247cc-a67f-48cf-a9e5-4a54c50887eb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_b80e4c36-fabd-43d4-816c-c63bda161506" xlink:to="loc_us-gaap_EquityComponentDomain_6d0247cc-a67f-48cf-a9e5-4a54c50887eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParentMember_59284926-a266-4d9c-a5b3-62297f402032" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6d0247cc-a67f-48cf-a9e5-4a54c50887eb" xlink:to="loc_us-gaap_ParentMember_59284926-a266-4d9c-a5b3-62297f402032" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_3423d93b-2660-4794-a362-67357a9ae604" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_59284926-a266-4d9c-a5b3-62297f402032" xlink:to="loc_us-gaap_CommonStockMember_3423d93b-2660-4794-a362-67357a9ae604" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_da1208f6-2c94-4faa-9369-be64d79a88cc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_59284926-a266-4d9c-a5b3-62297f402032" xlink:to="loc_us-gaap_TreasuryStockCommonMember_da1208f6-2c94-4faa-9369-be64d79a88cc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_5003218f-92f7-4b58-96a9-5107e58c090e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_59284926-a266-4d9c-a5b3-62297f402032" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_5003218f-92f7-4b58-96a9-5107e58c090e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_30ca7b38-8b5e-4b13-8ad5-a8882234cf20" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_59284926-a266-4d9c-a5b3-62297f402032" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_30ca7b38-8b5e-4b13-8ad5-a8882234cf20" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_47024546-d5e5-43fc-8be8-5853f6380c3f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ParentMember_59284926-a266-4d9c-a5b3-62297f402032" xlink:to="loc_us-gaap_RetainedEarningsMember_47024546-d5e5-43fc-8be8-5853f6380c3f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_6f2bab47-3426-4e4e-8332-5aa2fb0ddb89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_6d0247cc-a67f-48cf-a9e5-4a54c50887eb" xlink:to="loc_us-gaap_NoncontrollingInterestMember_6f2bab47-3426-4e4e-8332-5aa2fb0ddb89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_21b9c20a-b27f-4653-86aa-6c8473dcc133" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_027ac73d-87ef-4d8a-9ac5-972af57b7073" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_027ac73d-87ef-4d8a-9ac5-972af57b7073" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_0e19f3be-8db3-4ef2-a0b1-a30e7412f99c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_0e19f3be-8db3-4ef2-a0b1-a30e7412f99c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_7cf82d21-3a4e-4086-97fb-2037c422d2b1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_TreasuryStockCommonShares_7cf82d21-3a4e-4086-97fb-2037c422d2b1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_29db1919-4a64-4d47-9897-73a9dfd7a097" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_29db1919-4a64-4d47-9897-73a9dfd7a097" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_529143ab-6284-4111-bb65-670b6300cf15" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_529143ab-6284-4111-bb65-670b6300cf15" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_96400497-294a-4355-b434-3697ce5599f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_96400497-294a-4355-b434-3697ce5599f6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_e159168f-b8ee-4a97-8204-92a718fa2707" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_e159168f-b8ee-4a97-8204-92a718fa2707" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_6198f419-e712-4a85-9754-f1f8ed889bf4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_6198f419-e712-4a85-9754-f1f8ed889bf4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_bc6f47f6-0ed8-485e-b9bb-c09f75062d0a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_bc6f47f6-0ed8-485e-b9bb-c09f75062d0a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_0a9ecc59-19a1-4ad0-9479-a20d3df869a1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_0a9ecc59-19a1-4ad0-9479-a20d3df869a1" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_IncreaseDecreaseFromSubsidiaryEquityIssuance_154d650c-62b4-4f67-8a77-88dd45809f56" xlink:href="unfi-20250802.xsd#unfi_IncreaseDecreaseFromSubsidiaryEquityIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_unfi_IncreaseDecreaseFromSubsidiaryEquityIssuance_154d650c-62b4-4f67-8a77-88dd45809f56" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_0ea3a12f-f771-488e-baaf-37eb74f6b604" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_2e26c9d8-489b-44ea-b4b2-0da56efbbb33" xlink:to="loc_us-gaap_ProfitLoss_0ea3a12f-f771-488e-baaf-37eb74f6b604" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_ad46f862-641b-4bf7-b3b9-1e6880483388" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_4d09d07a-cf95-4a2f-8f29-50ccd983e9c1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonShares_abb9baca-48f3-4aca-ab01-32af0e91fbfc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonShares"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/SIGNIFICANTACCOUNTINGPOLICIESCostofSalesDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#SIGNIFICANTACCOUNTINGPOLICIESCostofSalesDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/SIGNIFICANTACCOUNTINGPOLICIESCostofSalesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_fe80ccd1-e1a8-4aa6-8025-ef6ae2b4ff89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_1bcdf706-650a-4e16-926f-25dc202df239" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_fe80ccd1-e1a8-4aa6-8025-ef6ae2b4ff89" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_1bcdf706-650a-4e16-926f-25dc202df239" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_bf8232d1-83ab-4076-86ca-dd32a55fc66f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_1bcdf706-650a-4e16-926f-25dc202df239" xlink:to="loc_srt_ProductOrServiceAxis_bf8232d1-83ab-4076-86ca-dd32a55fc66f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_bf8232d1-83ab-4076-86ca-dd32a55fc66f_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_bf8232d1-83ab-4076-86ca-dd32a55fc66f" xlink:to="loc_srt_ProductsAndServicesDomain_bf8232d1-83ab-4076-86ca-dd32a55fc66f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_5497d38e-0e4b-4b4a-a2d3-de845feec85f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_bf8232d1-83ab-4076-86ca-dd32a55fc66f" xlink:to="loc_srt_ProductsAndServicesDomain_5497d38e-0e4b-4b4a-a2d3-de845feec85f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShippingAndHandlingMember_cfe7d911-434e-4160-9dfc-2971693e935e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShippingAndHandlingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_5497d38e-0e4b-4b4a-a2d3-de845feec85f" xlink:to="loc_us-gaap_ShippingAndHandlingMember_cfe7d911-434e-4160-9dfc-2971693e935e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_0f6cb6a6-6f31-4439-9854-0b554f9eca39" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_fe80ccd1-e1a8-4aa6-8025-ef6ae2b4ff89" xlink:to="loc_us-gaap_OperatingExpenses_0f6cb6a6-6f31-4439-9854-0b554f9eca39" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/SIGNIFICANTACCOUNTINGPOLICIESIntangibleAssetsWithDefiniteLivesDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#SIGNIFICANTACCOUNTINGPOLICIESIntangibleAssetsWithDefiniteLivesDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/SIGNIFICANTACCOUNTINGPOLICIESIntangibleAssetsWithDefiniteLivesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_5d9139bb-ff0c-426b-83ee-8d905ecf87e0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_35c2f8d0-641b-4cc4-a0bb-7254cbc67633" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_5d9139bb-ff0c-426b-83ee-8d905ecf87e0" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_35c2f8d0-641b-4cc4-a0bb-7254cbc67633" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_34c26681-bdc3-410b-b59f-1a0b94465b10" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_35c2f8d0-641b-4cc4-a0bb-7254cbc67633" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_34c26681-bdc3-410b-b59f-1a0b94465b10" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_34c26681-bdc3-410b-b59f-1a0b94465b10_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_34c26681-bdc3-410b-b59f-1a0b94465b10" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_34c26681-bdc3-410b-b59f-1a0b94465b10_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_13cb9bee-5729-455b-9c53-188303c3d29f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_34c26681-bdc3-410b-b59f-1a0b94465b10" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_13cb9bee-5729-455b-9c53-188303c3d29f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_7071cd1f-72c6-48fc-b95b-901f3c193fe6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_13cb9bee-5729-455b-9c53-188303c3d29f" xlink:to="loc_us-gaap_CustomerRelationshipsMember_7071cd1f-72c6-48fc-b95b-901f3c193fe6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_7129ec6f-1ca1-42ac-96b9-f59ebbe66055" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TrademarksAndTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_13cb9bee-5729-455b-9c53-188303c3d29f" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_7129ec6f-1ca1-42ac-96b9-f59ebbe66055" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_FavorableOperatingLeasesMember_66d5fb79-4c01-41df-806c-217ae8f4f8f4" xlink:href="unfi-20250802.xsd#unfi_FavorableOperatingLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_13cb9bee-5729-455b-9c53-188303c3d29f" xlink:to="loc_unfi_FavorableOperatingLeasesMember_66d5fb79-4c01-41df-806c-217ae8f4f8f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_PharmacyPrescriptionFilesMember_b66dea86-a840-4879-9284-70d78856cffb" xlink:href="unfi-20250802.xsd#unfi_PharmacyPrescriptionFilesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_13cb9bee-5729-455b-9c53-188303c3d29f" xlink:to="loc_unfi_PharmacyPrescriptionFilesMember_b66dea86-a840-4879-9284-70d78856cffb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_186a1108-c676-42ce-880d-381033a7277a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_35c2f8d0-641b-4cc4-a0bb-7254cbc67633" xlink:to="loc_srt_RangeAxis_186a1108-c676-42ce-880d-381033a7277a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_186a1108-c676-42ce-880d-381033a7277a_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_186a1108-c676-42ce-880d-381033a7277a" xlink:to="loc_srt_RangeMember_186a1108-c676-42ce-880d-381033a7277a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3d747ecf-2c46-4db9-908e-55e67c59fce5" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_186a1108-c676-42ce-880d-381033a7277a" xlink:to="loc_srt_RangeMember_3d747ecf-2c46-4db9-908e-55e67c59fce5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_6d583492-36c1-451f-ae1e-fbf76d4660e0" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3d747ecf-2c46-4db9-908e-55e67c59fce5" xlink:to="loc_srt_MinimumMember_6d583492-36c1-451f-ae1e-fbf76d4660e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_0d937b09-2586-47fb-a48a-32950fa2bbe2" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3d747ecf-2c46-4db9-908e-55e67c59fce5" xlink:to="loc_srt_MaximumMember_0d937b09-2586-47fb-a48a-32950fa2bbe2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_8cea1336-e7f7-4b39-aa95-cb90e4761866" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_5d9139bb-ff0c-426b-83ee-8d905ecf87e0" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_8cea1336-e7f7-4b39-aa95-cb90e4761866" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/SIGNIFICANTACCOUNTINGPOLICIESTreasuryStockDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#SIGNIFICANTACCOUNTINGPOLICIESTreasuryStockDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/SIGNIFICANTACCOUNTINGPOLICIESTreasuryStockDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityClassOfTreasuryStockLineItems_77be9146-9403-4ee7-a08b-a1322b126d44" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityClassOfTreasuryStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfTreasuryStockTable_d3634fcd-ce60-4e91-b164-41de01c7317c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ClassOfTreasuryStockTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_77be9146-9403-4ee7-a08b-a1322b126d44" xlink:to="loc_us-gaap_ClassOfTreasuryStockTable_d3634fcd-ce60-4e91-b164-41de01c7317c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_78fdf12c-b82e-4aa5-a0d0-b811c782cd8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfTreasuryStockTable_d3634fcd-ce60-4e91-b164-41de01c7317c" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_78fdf12c-b82e-4aa5-a0d0-b811c782cd8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_78fdf12c-b82e-4aa5-a0d0-b811c782cd8b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_78fdf12c-b82e-4aa5-a0d0-b811c782cd8b" xlink:to="loc_us-gaap_EquityComponentDomain_78fdf12c-b82e-4aa5-a0d0-b811c782cd8b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_b555b04e-b25c-43ce-88f2-65fddef94047" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_78fdf12c-b82e-4aa5-a0d0-b811c782cd8b" xlink:to="loc_us-gaap_EquityComponentDomain_b555b04e-b25c-43ce-88f2-65fddef94047" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_80e9d60c-49fb-4144-b3d2-d3174f236113" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_b555b04e-b25c-43ce-88f2-65fddef94047" xlink:to="loc_us-gaap_TreasuryStockCommonMember_80e9d60c-49fb-4144-b3d2-d3174f236113" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramAuthorizedAmount1_a62c22d4-3499-4fa2-9ebf-87fa9a61c393" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_77be9146-9403-4ee7-a08b-a1322b126d44" xlink:to="loc_srt_StockRepurchaseProgramAuthorizedAmount1_a62c22d4-3499-4fa2-9ebf-87fa9a61c393" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramPeriodInForce1_8895ea4a-9bd9-45c8-95a4-1400f329d41a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchaseProgramPeriodInForce1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_77be9146-9403-4ee7-a08b-a1322b126d44" xlink:to="loc_us-gaap_StockRepurchaseProgramPeriodInForce1_8895ea4a-9bd9-45c8-95a4-1400f329d41a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_68703aef-1579-4988-8093-a1922910ee35" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_77be9146-9403-4ee7-a08b-a1322b126d44" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_68703aef-1579-4988-8093-a1922910ee35" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_9f2df439-af43-45be-89fb-732454657822" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_77be9146-9403-4ee7-a08b-a1322b126d44" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_9f2df439-af43-45be-89fb-732454657822" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_0f9f8bd6-785b-47c8-a68b-7e112dabb676" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityClassOfTreasuryStockLineItems_77be9146-9403-4ee7-a08b-a1322b126d44" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_0f9f8bd6-785b-47c8-a68b-7e112dabb676" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/SIGNIFICANTACCOUNTINGPOLICIESSelfInsuranceLiabilitiesNarrativeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#SIGNIFICANTACCOUNTINGPOLICIESSelfInsuranceLiabilitiesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/SIGNIFICANTACCOUNTINGPOLICIESSelfInsuranceLiabilitiesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_37fe16e0-39b5-4075-b14d-95baa3089d95" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_2e260e4c-272c-441b-bff9-b05f719eb462" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_37fe16e0-39b5-4075-b14d-95baa3089d95" xlink:to="loc_us-gaap_LossContingenciesTable_2e260e4c-272c-441b-bff9-b05f719eb462" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_7a823208-9ad5-4980-bf1b-ecec3ccf2303" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_2e260e4c-272c-441b-bff9-b05f719eb462" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_7a823208-9ad5-4980-bf1b-ecec3ccf2303" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_7a823208-9ad5-4980-bf1b-ecec3ccf2303_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_7a823208-9ad5-4980-bf1b-ecec3ccf2303" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_7a823208-9ad5-4980-bf1b-ecec3ccf2303_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_847266ac-0270-4795-a3c0-4832a1ddfa50" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_7a823208-9ad5-4980-bf1b-ecec3ccf2303" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_847266ac-0270-4795-a3c0-4832a1ddfa50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_AccruedExpensesAndOtherCurrentLiabilitiesMember_b33a004b-4528-4891-b912-cf1757a115d3" xlink:href="unfi-20250802.xsd#unfi_AccruedExpensesAndOtherCurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_847266ac-0270-4795-a3c0-4832a1ddfa50" xlink:to="loc_unfi_AccruedExpensesAndOtherCurrentLiabilitiesMember_b33a004b-4528-4891-b912-cf1757a115d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_OtherLongTermLiabilitiesMember_223519c2-75c6-4a84-a590-e02faa8a6c60" xlink:href="unfi-20250802.xsd#unfi_OtherLongTermLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_847266ac-0270-4795-a3c0-4832a1ddfa50" xlink:to="loc_unfi_OtherLongTermLiabilitiesMember_223519c2-75c6-4a84-a590-e02faa8a6c60" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyAccrualInsuranceRelatedAssessmentDiscountRate_dc566455-0caa-4c3f-a145-10640c3542bc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyAccrualInsuranceRelatedAssessmentDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_37fe16e0-39b5-4075-b14d-95baa3089d95" xlink:to="loc_us-gaap_LossContingencyAccrualInsuranceRelatedAssessmentDiscountRate_dc566455-0caa-4c3f-a145-10640c3542bc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SelfInsuranceReserveCurrent_81816763-4bd3-4002-b469-14fedc239834" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SelfInsuranceReserveCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_37fe16e0-39b5-4075-b14d-95baa3089d95" xlink:to="loc_us-gaap_SelfInsuranceReserveCurrent_81816763-4bd3-4002-b469-14fedc239834" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SelfInsuranceReserveNoncurrent_27926f34-5a89-43ef-8966-72d4c30edaf2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SelfInsuranceReserveNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_37fe16e0-39b5-4075-b14d-95baa3089d95" xlink:to="loc_us-gaap_SelfInsuranceReserveNoncurrent_27926f34-5a89-43ef-8966-72d4c30edaf2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InsuranceLiabilityDiscount_b98dd753-b917-4270-ad40-051da57f1876" xlink:href="unfi-20250802.xsd#unfi_InsuranceLiabilityDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_37fe16e0-39b5-4075-b14d-95baa3089d95" xlink:to="loc_unfi_InsuranceLiabilityDiscount_b98dd753-b917-4270-ad40-051da57f1876" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DuefromInsuranceCompanies_e8da67b2-2bf3-4205-8fd6-594868fedd49" xlink:href="unfi-20250802.xsd#unfi_DuefromInsuranceCompanies"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_37fe16e0-39b5-4075-b14d-95baa3089d95" xlink:to="loc_unfi_DuefromInsuranceCompanies_e8da67b2-2bf3-4205-8fd6-594868fedd49" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/REVENUERECOGNITIONNarrativeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#REVENUERECOGNITIONNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/REVENUERECOGNITIONNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_92518259-44a8-4525-854e-92ddf271197b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3dd8fd0c-858a-43f4-8edd-2eb21ea2e551" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_92518259-44a8-4525-854e-92ddf271197b" xlink:to="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3dd8fd0c-858a-43f4-8edd-2eb21ea2e551" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_3770bb43-e5db-4a16-92b0-37c7a12a76bb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3dd8fd0c-858a-43f4-8edd-2eb21ea2e551" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_3770bb43-e5db-4a16-92b0-37c7a12a76bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_3770bb43-e5db-4a16-92b0-37c7a12a76bb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_3770bb43-e5db-4a16-92b0-37c7a12a76bb" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_3770bb43-e5db-4a16-92b0-37c7a12a76bb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_162631b9-9d04-4c66-b07e-ddc9e5c46ac7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_3770bb43-e5db-4a16-92b0-37c7a12a76bb" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_162631b9-9d04-4c66-b07e-ddc9e5c46ac7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_2dc88139-c707-4d32-aedb-5817ef7225ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_162631b9-9d04-4c66-b07e-ddc9e5c46ac7" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_2dc88139-c707-4d32-aedb-5817ef7225ad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_eda481b5-f1cb-4fe1-ab9b-0bc10e8e9d28" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3dd8fd0c-858a-43f4-8edd-2eb21ea2e551" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_eda481b5-f1cb-4fe1-ab9b-0bc10e8e9d28" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_eda481b5-f1cb-4fe1-ab9b-0bc10e8e9d28_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_eda481b5-f1cb-4fe1-ab9b-0bc10e8e9d28" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_eda481b5-f1cb-4fe1-ab9b-0bc10e8e9d28_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_87244650-c823-4a7f-9aba-2d72e6bf299e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_eda481b5-f1cb-4fe1-ab9b-0bc10e8e9d28" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_87244650-c823-4a7f-9aba-2d72e6bf299e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductConcentrationRiskMember_f9b54542-bff0-4eab-98c0-4a04c2d7d96b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProductConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_87244650-c823-4a7f-9aba-2d72e6bf299e" xlink:to="loc_us-gaap_ProductConcentrationRiskMember_f9b54542-bff0-4eab-98c0-4a04c2d7d96b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_8959039f-ee1e-4d9d-92ac-b5a0eff96ec8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_87244650-c823-4a7f-9aba-2d72e6bf299e" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_8959039f-ee1e-4d9d-92ac-b5a0eff96ec8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_4a072f8a-9301-45ce-8132-5094039b6f9b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3dd8fd0c-858a-43f4-8edd-2eb21ea2e551" xlink:to="loc_srt_ProductOrServiceAxis_4a072f8a-9301-45ce-8132-5094039b6f9b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_4a072f8a-9301-45ce-8132-5094039b6f9b_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_4a072f8a-9301-45ce-8132-5094039b6f9b" xlink:to="loc_srt_ProductsAndServicesDomain_4a072f8a-9301-45ce-8132-5094039b6f9b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_52d1e1ff-3cf4-4408-a560-d9eeb5ee658c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_4a072f8a-9301-45ce-8132-5094039b6f9b" xlink:to="loc_srt_ProductsAndServicesDomain_52d1e1ff-3cf4-4408-a560-d9eeb5ee658c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ProfessionalServicesMember_7625ce1e-178e-4e1a-bac7-e57e49f68b47" xlink:href="unfi-20250802.xsd#unfi_ProfessionalServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_52d1e1ff-3cf4-4408-a560-d9eeb5ee658c" xlink:to="loc_unfi_ProfessionalServicesMember_7625ce1e-178e-4e1a-bac7-e57e49f68b47" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_7505e6b7-3337-4ff4-8689-c78fe075fa79" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_3dd8fd0c-858a-43f4-8edd-2eb21ea2e551" xlink:to="loc_srt_MajorCustomersAxis_7505e6b7-3337-4ff4-8689-c78fe075fa79" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_7505e6b7-3337-4ff4-8689-c78fe075fa79_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_7505e6b7-3337-4ff4-8689-c78fe075fa79" xlink:to="loc_srt_NameOfMajorCustomerDomain_7505e6b7-3337-4ff4-8689-c78fe075fa79_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_9f425267-69f4-414f-978b-60795855716a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_7505e6b7-3337-4ff4-8689-c78fe075fa79" xlink:to="loc_srt_NameOfMajorCustomerDomain_9f425267-69f4-414f-978b-60795855716a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_WholeFoodsMarketMember_db9c8685-edc6-4465-b7e1-2de97d635f2b" xlink:href="unfi-20250802.xsd#unfi_WholeFoodsMarketMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_9f425267-69f4-414f-978b-60795855716a" xlink:to="loc_unfi_WholeFoodsMarketMember_db9c8685-edc6-4465-b7e1-2de97d635f2b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_a722ecd1-88cb-43b5-b383-5d7493715a50" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_92518259-44a8-4525-854e-92ddf271197b" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_a722ecd1-88cb-43b5-b383-5d7493715a50" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_AccountsReceivableSaleAuthorizedAmount_e0705d06-918e-415c-962c-f1a636175b71" xlink:href="unfi-20250802.xsd#unfi_AccountsReceivableSaleAuthorizedAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_92518259-44a8-4525-854e-92ddf271197b" xlink:to="loc_unfi_AccountsReceivableSaleAuthorizedAmount_e0705d06-918e-415c-962c-f1a636175b71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableSale_9ac7fd1b-8b7f-4cc0-977e-58d09a6b1e78" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccountsReceivableSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_92518259-44a8-4525-854e-92ddf271197b" xlink:to="loc_us-gaap_AccountsReceivableSale_9ac7fd1b-8b7f-4cc0-977e-58d09a6b1e78" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfAccountsReceivable_2a8d3f2c-8b96-4340-9273-126f1ea750b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnSaleOfAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems_92518259-44a8-4525-854e-92ddf271197b" xlink:to="loc_us-gaap_GainLossOnSaleOfAccountsReceivable_2a8d3f2c-8b96-4340-9273-126f1ea750b5" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/RESTRUCTURINGACQUISITIONANDINTEGRATIONRELATEDEXPENSESScheduleofExpenseDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#RESTRUCTURINGACQUISITIONANDINTEGRATIONRELATEDEXPENSESScheduleofExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/RESTRUCTURINGACQUISITIONANDINTEGRATIONRELATEDEXPENSESScheduleofExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_932dc704-9efd-46d1-a8c7-62141003b81e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_c90a878e-ad62-4f21-bd74-67806d91195d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_932dc704-9efd-46d1-a8c7-62141003b81e" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_c90a878e-ad62-4f21-bd74-67806d91195d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_5f481e2c-c67b-4896-a8da-87c302a71f8c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_c90a878e-ad62-4f21-bd74-67806d91195d" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_5f481e2c-c67b-4896-a8da-87c302a71f8c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_5f481e2c-c67b-4896-a8da-87c302a71f8c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_5f481e2c-c67b-4896-a8da-87c302a71f8c" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_5f481e2c-c67b-4896-a8da-87c302a71f8c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_915f27d7-2a88-4ee0-b7bf-6e8961d2d40c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_5f481e2c-c67b-4896-a8da-87c302a71f8c" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_915f27d7-2a88-4ee0-b7bf-6e8961d2d40c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractTerminationMember_74f59be9-5692-400a-8455-96e959649aa5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractTerminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_915f27d7-2a88-4ee0-b7bf-6e8961d2d40c" xlink:to="loc_us-gaap_ContractTerminationMember_74f59be9-5692-400a-8455-96e959649aa5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeSeveranceMember_eaf32906-f771-49f6-8160-68882c904d72" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeSeveranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_915f27d7-2a88-4ee0-b7bf-6e8961d2d40c" xlink:to="loc_us-gaap_EmployeeSeveranceMember_eaf32906-f771-49f6-8160-68882c904d72" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FacilityClosingMember_c7f30348-a2f0-4828-a888-9e19ba99a20a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FacilityClosingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_915f27d7-2a88-4ee0-b7bf-6e8961d2d40c" xlink:to="loc_us-gaap_FacilityClosingMember_c7f30348-a2f0-4828-a888-9e19ba99a20a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringSettlementAndImpairmentProvisions_ec0ae9df-f062-44a0-8195-b5bf4105604f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringSettlementAndImpairmentProvisions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_932dc704-9efd-46d1-a8c7-62141003b81e" xlink:to="loc_us-gaap_RestructuringSettlementAndImpairmentProvisions_ec0ae9df-f062-44a0-8195-b5bf4105604f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/RESTRUCTURINGACQUISITIONANDINTEGRATIONRELATEDEXPENSESNarrativeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#RESTRUCTURINGACQUISITIONANDINTEGRATIONRELATEDEXPENSESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/RESTRUCTURINGACQUISITIONANDINTEGRATIONRELATEDEXPENSESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_c03ba0c0-6e2d-4c12-86a3-04b46f998f73" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_59ac7edc-fa68-41f7-9d68-128536a2d2ef" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_c03ba0c0-6e2d-4c12-86a3-04b46f998f73" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_59ac7edc-fa68-41f7-9d68-128536a2d2ef" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_205f6739-6b13-4ffc-bab3-57dd2f3ed187" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_59ac7edc-fa68-41f7-9d68-128536a2d2ef" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_205f6739-6b13-4ffc-bab3-57dd2f3ed187" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_205f6739-6b13-4ffc-bab3-57dd2f3ed187_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_205f6739-6b13-4ffc-bab3-57dd2f3ed187" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_205f6739-6b13-4ffc-bab3-57dd2f3ed187_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_45a4fc73-bd9f-4935-ba06-8edc3fee58d5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_205f6739-6b13-4ffc-bab3-57dd2f3ed187" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_45a4fc73-bd9f-4935-ba06-8edc3fee58d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractTerminationMember_3997818b-907f-4936-812b-38cb26753f04" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractTerminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_45a4fc73-bd9f-4935-ba06-8edc3fee58d5" xlink:to="loc_us-gaap_ContractTerminationMember_3997818b-907f-4936-812b-38cb26753f04" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementScenarioAxis_451b53ac-2583-49a0-8a84-7d2385a42883" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_StatementScenarioAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_59ac7edc-fa68-41f7-9d68-128536a2d2ef" xlink:to="loc_srt_StatementScenarioAxis_451b53ac-2583-49a0-8a84-7d2385a42883" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_451b53ac-2583-49a0-8a84-7d2385a42883_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_451b53ac-2583-49a0-8a84-7d2385a42883" xlink:to="loc_srt_ScenarioUnspecifiedDomain_451b53ac-2583-49a0-8a84-7d2385a42883_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioUnspecifiedDomain_a69a40a8-3a07-45a3-8701-6c5583259d03" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioUnspecifiedDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_451b53ac-2583-49a0-8a84-7d2385a42883" xlink:to="loc_srt_ScenarioUnspecifiedDomain_a69a40a8-3a07-45a3-8701-6c5583259d03" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScenarioForecastMember_0e2fb030-71ec-4540-ba9c-9f7fcb8843a4" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ScenarioForecastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_a69a40a8-3a07-45a3-8701-6c5583259d03" xlink:to="loc_srt_ScenarioForecastMember_0e2fb030-71ec-4540-ba9c-9f7fcb8843a4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_0589f350-dd8d-42f8-971c-13476d2e1614" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_59ac7edc-fa68-41f7-9d68-128536a2d2ef" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_0589f350-dd8d-42f8-971c-13476d2e1614" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_0589f350-dd8d-42f8-971c-13476d2e1614_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_0589f350-dd8d-42f8-971c-13476d2e1614" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_0589f350-dd8d-42f8-971c-13476d2e1614_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_ce55e331-7f16-417b-932d-fafb424a59f4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_0589f350-dd8d-42f8-971c-13476d2e1614" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_ce55e331-7f16-417b-932d-fafb424a59f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_90bfc23f-480b-43a6-8721-3b701d41b4d1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_ce55e331-7f16-417b-932d-fafb424a59f4" xlink:to="loc_us-gaap_SubsequentEventMember_90bfc23f-480b-43a6-8721-3b701d41b4d1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringSettlementAndImpairmentProvisions_692740c9-25ce-4e70-a72d-fd44ef2a3c45" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringSettlementAndImpairmentProvisions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_c03ba0c0-6e2d-4c12-86a3-04b46f998f73" xlink:to="loc_us-gaap_RestructuringSettlementAndImpairmentProvisions_692740c9-25ce-4e70-a72d-fd44ef2a3c45" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRestructuring_0a0fb1d8-dbf4-4f00-96d9-b370bb1ac0e7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForRestructuring"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_c03ba0c0-6e2d-4c12-86a3-04b46f998f73" xlink:to="loc_us-gaap_PaymentsForRestructuring_0a0fb1d8-dbf4-4f00-96d9-b370bb1ac0e7" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/RESTRUCTURINGACQUISITIONANDINTEGRATIONRELATEDEXPENSESScheduleofRestructuringLiabilitiesDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#RESTRUCTURINGACQUISITIONANDINTEGRATIONRELATEDEXPENSESScheduleofRestructuringLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/RESTRUCTURINGACQUISITIONANDINTEGRATIONRELATEDEXPENSESScheduleofRestructuringLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_c95d22e4-0010-4f55-b316-9e8c84d6ea72" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_61ec7376-f39a-4d16-8914-4098399876d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_c95d22e4-0010-4f55-b316-9e8c84d6ea72" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_61ec7376-f39a-4d16-8914-4098399876d8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_76da8397-ada6-43bd-b11c-102d1579e2c8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_61ec7376-f39a-4d16-8914-4098399876d8" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_76da8397-ada6-43bd-b11c-102d1579e2c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_76da8397-ada6-43bd-b11c-102d1579e2c8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_76da8397-ada6-43bd-b11c-102d1579e2c8" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_76da8397-ada6-43bd-b11c-102d1579e2c8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_c92cefcd-ab28-41a9-b9a6-eb2ad9fd0783" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_76da8397-ada6-43bd-b11c-102d1579e2c8" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_c92cefcd-ab28-41a9-b9a6-eb2ad9fd0783" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeSeveranceMember_f5cb81e6-e096-44d2-9839-0bde2c83ff94" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeSeveranceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_c92cefcd-ab28-41a9-b9a6-eb2ad9fd0783" xlink:to="loc_us-gaap_EmployeeSeveranceMember_f5cb81e6-e096-44d2-9839-0bde2c83ff94" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractTerminationMember_774716a3-53b3-4b55-88b3-03471a76c58d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ContractTerminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_c92cefcd-ab28-41a9-b9a6-eb2ad9fd0783" xlink:to="loc_us-gaap_ContractTerminationMember_774716a3-53b3-4b55-88b3-03471a76c58d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserveRollForward_8060f1e6-060d-42af-8a1d-17c5911ca437" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringReserveRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_c95d22e4-0010-4f55-b316-9e8c84d6ea72" xlink:to="loc_us-gaap_RestructuringReserveRollForward_8060f1e6-060d-42af-8a1d-17c5911ca437" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_cc93ef7f-477a-4165-be8b-e40005dbe5c6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringReserve"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_8060f1e6-060d-42af-8a1d-17c5911ca437" xlink:to="loc_us-gaap_RestructuringReserve_cc93ef7f-477a-4165-be8b-e40005dbe5c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RestructuringSettlementAndImpairmentProvisionsNet_8770e7b9-984f-435e-986c-d37748750b11" xlink:href="unfi-20250802.xsd#unfi_RestructuringSettlementAndImpairmentProvisionsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_8060f1e6-060d-42af-8a1d-17c5911ca437" xlink:to="loc_unfi_RestructuringSettlementAndImpairmentProvisionsNet_8770e7b9-984f-435e-986c-d37748750b11" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForRestructuring_c4bba151-c365-415f-b1d9-3eb1f2db7e35" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentsForRestructuring"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringReserveRollForward_8060f1e6-060d-42af-8a1d-17c5911ca437" xlink:to="loc_us-gaap_PaymentsForRestructuring_c4bba151-c365-415f-b1d9-3eb1f2db7e35" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringReserve_dc43534d-6dc9-4444-adb5-249765cbdb4e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringReserve"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/PROPERTYANDEQUIPMENTNETPropertyandEquipmentNetDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#PROPERTYANDEQUIPMENTNETPropertyandEquipmentNetDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/PROPERTYANDEQUIPMENTNETPropertyandEquipmentNetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1823598a-5e40-4663-b6d6-a8572d48d8c8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_21d7289d-4618-45b7-96fa-e3577d542f51" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1823598a-5e40-4663-b6d6-a8572d48d8c8" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_21d7289d-4618-45b7-96fa-e3577d542f51" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_52200d01-30e6-48e7-ba99-af5776e76c50" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_21d7289d-4618-45b7-96fa-e3577d542f51" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_52200d01-30e6-48e7-ba99-af5776e76c50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_52200d01-30e6-48e7-ba99-af5776e76c50_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_52200d01-30e6-48e7-ba99-af5776e76c50" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_52200d01-30e6-48e7-ba99-af5776e76c50_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ab497f0c-0822-4fc7-b8d0-bd6208e3462f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_52200d01-30e6-48e7-ba99-af5776e76c50" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ab497f0c-0822-4fc7-b8d0-bd6208e3462f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_6691c8aa-f1b2-4cbd-a048-b16964ef46ff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ab497f0c-0822-4fc7-b8d0-bd6208e3462f" xlink:to="loc_us-gaap_LandMember_6691c8aa-f1b2-4cbd-a048-b16964ef46ff" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_659caf87-988e-42c1-acfe-45066a45eebc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ab497f0c-0822-4fc7-b8d0-bd6208e3462f" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_659caf87-988e-42c1-acfe-45066a45eebc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_3dd2668b-1c54-43dd-ac4a-f8fff01b5892" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ab497f0c-0822-4fc7-b8d0-bd6208e3462f" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_3dd2668b-1c54-43dd-ac4a-f8fff01b5892" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquipmentMember_67ed628c-1974-42f3-94f9-5c2a5cdbb28a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ab497f0c-0822-4fc7-b8d0-bd6208e3462f" xlink:to="loc_us-gaap_EquipmentMember_67ed628c-1974-42f3-94f9-5c2a5cdbb28a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VehiclesMember_f27e092b-f69b-4663-a6cd-5a5c4b7abd48" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VehiclesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ab497f0c-0822-4fc7-b8d0-bd6208e3462f" xlink:to="loc_us-gaap_VehiclesMember_f27e092b-f69b-4663-a6cd-5a5c4b7abd48" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_FinanceLeaseAssetsMember_4328c4f5-7411-480d-8c2a-f835677ae543" xlink:href="unfi-20250802.xsd#unfi_FinanceLeaseAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ab497f0c-0822-4fc7-b8d0-bd6208e3462f" xlink:to="loc_unfi_FinanceLeaseAssetsMember_4328c4f5-7411-480d-8c2a-f835677ae543" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_35a6cf87-4dac-411f-9851-a0dbc50992fe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ab497f0c-0822-4fc7-b8d0-bd6208e3462f" xlink:to="loc_us-gaap_ConstructionInProgressMember_35a6cf87-4dac-411f-9851-a0dbc50992fe" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_ee51ec7e-4ba4-4ce2-8049-c54f62e52feb" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_21d7289d-4618-45b7-96fa-e3577d542f51" xlink:to="loc_srt_RangeAxis_ee51ec7e-4ba4-4ce2-8049-c54f62e52feb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ee51ec7e-4ba4-4ce2-8049-c54f62e52feb_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_ee51ec7e-4ba4-4ce2-8049-c54f62e52feb" xlink:to="loc_srt_RangeMember_ee51ec7e-4ba4-4ce2-8049-c54f62e52feb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_b8572864-9e15-4b3f-b7c2-0476e2e227a8" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_ee51ec7e-4ba4-4ce2-8049-c54f62e52feb" xlink:to="loc_srt_RangeMember_b8572864-9e15-4b3f-b7c2-0476e2e227a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_44a402f5-91ee-4ffa-bd42-a852d3e49bd9" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_b8572864-9e15-4b3f-b7c2-0476e2e227a8" xlink:to="loc_srt_MinimumMember_44a402f5-91ee-4ffa-bd42-a852d3e49bd9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_d4ac8f28-aff1-4a25-8ad5-facd0e6c440b" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_b8572864-9e15-4b3f-b7c2-0476e2e227a8" xlink:to="loc_srt_MaximumMember_d4ac8f28-aff1-4a25-8ad5-facd0e6c440b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_cb24f713-cc09-4288-93c8-b2ff99874a63" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1823598a-5e40-4663-b6d6-a8572d48d8c8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_cb24f713-cc09-4288-93c8-b2ff99874a63" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_9b0870f2-8286-45de-9939-d13095433540" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1823598a-5e40-4663-b6d6-a8572d48d8c8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetBeforeAccumulatedDepreciationAndAmortization_9b0870f2-8286-45de-9939-d13095433540" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_d9a0fb69-8686-4f76-b750-978402fddaf8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1823598a-5e40-4663-b6d6-a8572d48d8c8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAccumulatedDepreciationAndAmortization_d9a0fb69-8686-4f76-b750-978402fddaf8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_ed9090d0-e40d-44a5-abe9-0ed734ff8e88" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_1823598a-5e40-4663-b6d6-a8572d48d8c8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization_ed9090d0-e40d-44a5-abe9-0ed734ff8e88" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/PROPERTYANDEQUIPMENTNETNarrativeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#PROPERTYANDEQUIPMENTNETNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/PROPERTYANDEQUIPMENTNETNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongLivedAssetsHeldForSaleLineItems_a144f907-baf6-4920-bc59-2b0cd1f34267" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongLivedAssetsHeldForSaleLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfLongLivedAssetsHeldForSaleTable_9ccb1d68-391b-479f-b3f4-e8f7934673dd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfLongLivedAssetsHeldForSaleTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LongLivedAssetsHeldForSaleLineItems_a144f907-baf6-4920-bc59-2b0cd1f34267" xlink:to="loc_us-gaap_ScheduleOfLongLivedAssetsHeldForSaleTable_9ccb1d68-391b-479f-b3f4-e8f7934673dd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_f4ba1d5d-17e5-4a01-81e5-1599d35dddbf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLongLivedAssetsHeldForSaleTable_9ccb1d68-391b-479f-b3f4-e8f7934673dd" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_f4ba1d5d-17e5-4a01-81e5-1599d35dddbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_f4ba1d5d-17e5-4a01-81e5-1599d35dddbf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_f4ba1d5d-17e5-4a01-81e5-1599d35dddbf" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_f4ba1d5d-17e5-4a01-81e5-1599d35dddbf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ec7bfb1b-2519-4c8c-a761-d60982e8fbd3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_f4ba1d5d-17e5-4a01-81e5-1599d35dddbf" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ec7bfb1b-2519-4c8c-a761-d60982e8fbd3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentMember_cc0836e7-2672-4575-b3e6-d43376f94ce8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_ec7bfb1b-2519-4c8c-a761-d60982e8fbd3" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentMember_cc0836e7-2672-4575-b3e6-d43376f94ce8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_2a4e2298-1197-4e78-8ecb-fc70e98b1b84" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLongLivedAssetsHeldForSaleTable_9ccb1d68-391b-479f-b3f4-e8f7934673dd" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_2a4e2298-1197-4e78-8ecb-fc70e98b1b84" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_2a4e2298-1197-4e78-8ecb-fc70e98b1b84_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_2a4e2298-1197-4e78-8ecb-fc70e98b1b84" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_2a4e2298-1197-4e78-8ecb-fc70e98b1b84_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_9d7ceaee-a08f-4624-8ab0-b008bfed21ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_2a4e2298-1197-4e78-8ecb-fc70e98b1b84" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_9d7ceaee-a08f-4624-8ab0-b008bfed21ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_d4862e60-2010-4555-8117-57574d3265a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_9d7ceaee-a08f-4624-8ab0-b008bfed21ad" xlink:to="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_d4862e60-2010-4555-8117-57574d3265a0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_e2f6b53a-e8d8-4107-95de-037e30060a84" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_9d7ceaee-a08f-4624-8ab0-b008bfed21ad" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_e2f6b53a-e8d8-4107-95de-037e30060a84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0cbcf11f-1f9c-438b-80a9-23b8fbd83808" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfLongLivedAssetsHeldForSaleTable_9ccb1d68-391b-479f-b3f4-e8f7934673dd" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0cbcf11f-1f9c-438b-80a9-23b8fbd83808" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_0cbcf11f-1f9c-438b-80a9-23b8fbd83808_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0cbcf11f-1f9c-438b-80a9-23b8fbd83808" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_0cbcf11f-1f9c-438b-80a9-23b8fbd83808_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_82da3e52-37f4-4712-9ea0-1e74cd51cc64" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_0cbcf11f-1f9c-438b-80a9-23b8fbd83808" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_82da3e52-37f4-4712-9ea0-1e74cd51cc64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_PennsylvaniaDistributionCenterMember_e9ee20ba-7d3c-45d9-a1e8-218b13395025" xlink:href="unfi-20250802.xsd#unfi_PennsylvaniaDistributionCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_82da3e52-37f4-4712-9ea0-1e74cd51cc64" xlink:to="loc_unfi_PennsylvaniaDistributionCenterMember_e9ee20ba-7d3c-45d9-a1e8-218b13395025" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_CorporateOwnedOfficeLocationMember_28710d05-c419-4e97-895f-a920f9b63c24" xlink:href="unfi-20250802.xsd#unfi_CorporateOwnedOfficeLocationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_82da3e52-37f4-4712-9ea0-1e74cd51cc64" xlink:to="loc_unfi_CorporateOwnedOfficeLocationMember_28710d05-c419-4e97-895f-a920f9b63c24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_CertainLeasedAndOwnedDistributionCenterLocationsMember_4a4bd67e-f79b-4879-ad0d-e98d496c456d" xlink:href="unfi-20250802.xsd#unfi_CertainLeasedAndOwnedDistributionCenterLocationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_82da3e52-37f4-4712-9ea0-1e74cd51cc64" xlink:to="loc_unfi_CertainLeasedAndOwnedDistributionCenterLocationsMember_4a4bd67e-f79b-4879-ad0d-e98d496c456d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_CertainRetailStoreLocationsMember_9782590d-0e77-4683-b7e6-68c9477d8028" xlink:href="unfi-20250802.xsd#unfi_CertainRetailStoreLocationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_82da3e52-37f4-4712-9ea0-1e74cd51cc64" xlink:to="loc_unfi_CertainRetailStoreLocationsMember_9782590d-0e77-4683-b7e6-68c9477d8028" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestCostsCapitalized_a933b0ea-63e4-4fc7-a150-05f9b71a61b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestCostsCapitalized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongLivedAssetsHeldForSaleLineItems_a144f907-baf6-4920-bc59-2b0cd1f34267" xlink:to="loc_us-gaap_InterestCostsCapitalized_a933b0ea-63e4-4fc7-a150-05f9b71a61b0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_f355bc2e-82c6-4fa0-8dde-c54c80f3e771" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongLivedAssetsHeldForSaleLineItems_a144f907-baf6-4920-bc59-2b0cd1f34267" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_f355bc2e-82c6-4fa0-8dde-c54c80f3e771" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DisposalGroupNumberOfOfficeLocationsToBeDisposed_bc919b5d-6372-4cbb-be0e-584d7437af52" xlink:href="unfi-20250802.xsd#unfi_DisposalGroupNumberOfOfficeLocationsToBeDisposed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongLivedAssetsHeldForSaleLineItems_a144f907-baf6-4920-bc59-2b0cd1f34267" xlink:to="loc_unfi_DisposalGroupNumberOfOfficeLocationsToBeDisposed_bc919b5d-6372-4cbb-be0e-584d7437af52" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_5ec041e4-a55d-43b5-845c-bf7dc68f74e4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongLivedAssetsHeldForSaleLineItems_a144f907-baf6-4920-bc59-2b0cd1f34267" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_5ec041e4-a55d-43b5-845c-bf7dc68f74e4" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/GOODWILLANDINTANGIBLEASSETSNETNarrativeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#GOODWILLANDINTANGIBLEASSETSNETNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/GOODWILLANDINTANGIBLEASSETSNETNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_c401854c-d05c-4941-832f-7f21056b76d8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_aba364e6-bec7-4119-b0d4-6948ea5f5264" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_c401854c-d05c-4941-832f-7f21056b76d8" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_aba364e6-bec7-4119-b0d4-6948ea5f5264" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_54f1e47e-2557-4a70-85e4-e103829488f4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_aba364e6-bec7-4119-b0d4-6948ea5f5264" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_54f1e47e-2557-4a70-85e4-e103829488f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_54f1e47e-2557-4a70-85e4-e103829488f4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_54f1e47e-2557-4a70-85e4-e103829488f4" xlink:to="loc_us-gaap_SegmentDomain_54f1e47e-2557-4a70-85e4-e103829488f4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_7bf9afd4-f1f2-4923-869d-a617b8ecf84c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_54f1e47e-2557-4a70-85e4-e103829488f4" xlink:to="loc_us-gaap_SegmentDomain_7bf9afd4-f1f2-4923-869d-a617b8ecf84c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_NaturalSegmentMember_bd8c7b0a-7253-47fd-be87-e105a179283a" xlink:href="unfi-20250802.xsd#unfi_NaturalSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_7bf9afd4-f1f2-4923-869d-a617b8ecf84c" xlink:to="loc_unfi_NaturalSegmentMember_bd8c7b0a-7253-47fd-be87-e105a179283a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportingUnits_37643feb-259e-45ea-9a8c-4ef1e335de5a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NumberOfReportingUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_c401854c-d05c-4941-832f-7f21056b76d8" xlink:to="loc_us-gaap_NumberOfReportingUnits_37643feb-259e-45ea-9a8c-4ef1e335de5a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_ccd9ccbb-fe58-48e7-b314-6c8615824eab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_c401854c-d05c-4941-832f-7f21056b76d8" xlink:to="loc_us-gaap_Goodwill_ccd9ccbb-fe58-48e7-b314-6c8615824eab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_09e56c0e-6b1c-4f70-a890-bcdbb4c002fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairedAccumulatedImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_c401854c-d05c-4941-832f-7f21056b76d8" xlink:to="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_09e56c0e-6b1c-4f70-a890-bcdbb4c002fc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_8db7ef20-e58e-4b19-813f-f472e420a428" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_c401854c-d05c-4941-832f-7f21056b76d8" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_8db7ef20-e58e-4b19-813f-f472e420a428" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill_bb3782c5-450d-403a-9fad-330bf5f98dcd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_c401854c-d05c-4941-832f-7f21056b76d8" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsExcludingGoodwill_bb3782c5-450d-403a-9fad-330bf5f98dcd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentIntangibleAssetStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_7614bb41-69d8-4d95-a46d-c4370d3178b4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentIntangibleAssetStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_c401854c-d05c-4941-832f-7f21056b76d8" xlink:to="loc_us-gaap_ImpairmentIntangibleAssetStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_7614bb41-69d8-4d95-a46d-c4370d3178b4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_d57a9db7-fa72-4d1b-bd65-f3f2236d15fe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmortizationOfIntangibleAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_c401854c-d05c-4941-832f-7f21056b76d8" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_d57a9db7-fa72-4d1b-bd65-f3f2236d15fe" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/GOODWILLANDINTANGIBLEASSETSNETIdentifiableIntangibleAssetsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#GOODWILLANDINTANGIBLEASSETSNETIdentifiableIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/GOODWILLANDINTANGIBLEASSETSNETIdentifiableIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ScheduleofIntangibleAssetsLineItems_573fd9ab-347b-4d7f-a0a8-3ece553d0533" xlink:href="unfi-20250802.xsd#unfi_ScheduleofIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ScheduleofIntangibleAssetsTable_aa34c2eb-fc33-4899-82dc-b1c7220adbf2" xlink:href="unfi-20250802.xsd#unfi_ScheduleofIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_unfi_ScheduleofIntangibleAssetsLineItems_573fd9ab-347b-4d7f-a0a8-3ece553d0533" xlink:to="loc_unfi_ScheduleofIntangibleAssetsTable_aa34c2eb-fc33-4899-82dc-b1c7220adbf2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_371d1c18-89e3-40d4-a4be-ccfd76a95bfe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unfi_ScheduleofIntangibleAssetsTable_aa34c2eb-fc33-4899-82dc-b1c7220adbf2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_371d1c18-89e3-40d4-a4be-ccfd76a95bfe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_371d1c18-89e3-40d4-a4be-ccfd76a95bfe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_371d1c18-89e3-40d4-a4be-ccfd76a95bfe" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_371d1c18-89e3-40d4-a4be-ccfd76a95bfe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ca9cfde7-14ca-4fd7-a489-22192d52ed6c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_371d1c18-89e3-40d4-a4be-ccfd76a95bfe" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ca9cfde7-14ca-4fd7-a489-22192d52ed6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_c1dc5275-6739-45c2-8262-c8e5c329b7b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ca9cfde7-14ca-4fd7-a489-22192d52ed6c" xlink:to="loc_us-gaap_CustomerRelationshipsMember_c1dc5275-6739-45c2-8262-c8e5c329b7b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_PharmacyPrescriptionFilesMember_8463d3b2-b431-44b0-9ab5-01121afdd8bc" xlink:href="unfi-20250802.xsd#unfi_PharmacyPrescriptionFilesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ca9cfde7-14ca-4fd7-a489-22192d52ed6c" xlink:to="loc_unfi_PharmacyPrescriptionFilesMember_8463d3b2-b431-44b0-9ab5-01121afdd8bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_OperatingLeaseIntangibleMember_0d709b5e-d0b9-49af-a8c2-80bd71341e44" xlink:href="unfi-20250802.xsd#unfi_OperatingLeaseIntangibleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ca9cfde7-14ca-4fd7-a489-22192d52ed6c" xlink:to="loc_unfi_OperatingLeaseIntangibleMember_0d709b5e-d0b9-49af-a8c2-80bd71341e44" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_40e3c3bb-ce56-4617-8970-59c18b179654" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TrademarksAndTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_ca9cfde7-14ca-4fd7-a489-22192d52ed6c" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_40e3c3bb-ce56-4617-8970-59c18b179654" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_17f7aa1d-d16d-461b-9e64-2f4b80e8d9b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_unfi_ScheduleofIntangibleAssetsTable_aa34c2eb-fc33-4899-82dc-b1c7220adbf2" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_17f7aa1d-d16d-461b-9e64-2f4b80e8d9b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_17f7aa1d-d16d-461b-9e64-2f4b80e8d9b9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_17f7aa1d-d16d-461b-9e64-2f4b80e8d9b9" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_17f7aa1d-d16d-461b-9e64-2f4b80e8d9b9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_ded744cd-bb69-4c45-b2ba-777d89ec4df0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_17f7aa1d-d16d-461b-9e64-2f4b80e8d9b9" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_ded744cd-bb69-4c45-b2ba-777d89ec4df0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_81753e69-849f-4c23-b151-0948064442dc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TrademarksAndTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_ded744cd-bb69-4c45-b2ba-777d89ec4df0" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_81753e69-849f-4c23-b151-0948064442dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_ee1d40f9-987a-4c2f-b4d6-695b1836a9ae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_ScheduleofIntangibleAssetsLineItems_573fd9ab-347b-4d7f-a0a8-3ece553d0533" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_ee1d40f9-987a-4c2f-b4d6-695b1836a9ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_f8bd876e-9500-4b98-a120-3c1cfa230f8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_ee1d40f9-987a-4c2f-b4d6-695b1836a9ae" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_f8bd876e-9500-4b98-a120-3c1cfa230f8b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_325e4d23-4750-4b2f-bd8f-de9741618a5a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_ee1d40f9-987a-4c2f-b4d6-695b1836a9ae" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_325e4d23-4750-4b2f-bd8f-de9741618a5a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_b3cb442a-ae00-4b1d-8ff7-b235b22f86bc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsRollForward_ee1d40f9-987a-4c2f-b4d6-695b1836a9ae" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_b3cb442a-ae00-4b1d-8ff7-b235b22f86bc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_57ae5c61-a963-4e31-8757-64c603a612ba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_ScheduleofIntangibleAssetsLineItems_573fd9ab-347b-4d7f-a0a8-3ece553d0533" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_57ae5c61-a963-4e31-8757-64c603a612ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_1d258c8c-de8b-4937-a766-1a64cfacf461" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsGrossExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_57ae5c61-a963-4e31-8757-64c603a612ba" xlink:to="loc_us-gaap_IntangibleAssetsGrossExcludingGoodwill_1d258c8c-de8b-4937-a766-1a64cfacf461" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_2ec06709-5bc7-4bfa-966b-d46f84dbca4e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_IndefiniteLivedIntangibleAssetsGross_16fb83ab-f2a4-424b-ab43-8468d6eae1ad" xlink:href="unfi-20250802.xsd#unfi_IndefiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_57ae5c61-a963-4e31-8757-64c603a612ba" xlink:to="loc_unfi_IndefiniteLivedIntangibleAssetsGross_16fb83ab-f2a4-424b-ab43-8468d6eae1ad" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_IndefiniteLivedIntangibleAssetsNet_b2f159e4-0030-4d4b-9b6f-3d03de8006bd" xlink:href="unfi-20250802.xsd#unfi_IndefiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwillAbstract_57ae5c61-a963-4e31-8757-64c603a612ba" xlink:to="loc_unfi_IndefiniteLivedIntangibleAssetsNet_b2f159e4-0030-4d4b-9b6f-3d03de8006bd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_25e35f06-5c3e-4869-9a30-fe42c424317e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_ScheduleofIntangibleAssetsLineItems_573fd9ab-347b-4d7f-a0a8-3ece553d0533" xlink:to="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_25e35f06-5c3e-4869-9a30-fe42c424317e" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/FAIRVALUEMEASUREMENTSOFFINANCIALINSTRUMENTSRecurringFairValueMeasurementsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#FAIRVALUEMEASUREMENTSOFFINANCIALINSTRUMENTSRecurringFairValueMeasurementsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/FAIRVALUEMEASUREMENTSOFFINANCIALINSTRUMENTSRecurringFairValueMeasurementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_add221b7-482b-468f-b2a4-a4a1d4c5ff4b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_53ebad3d-bb7d-4b5d-832d-38c33c957b83" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_add221b7-482b-468f-b2a4-a4a1d4c5ff4b" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_53ebad3d-bb7d-4b5d-832d-38c33c957b83" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_606002c3-d68b-4b74-a766-1256348e6a9a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_53ebad3d-bb7d-4b5d-832d-38c33c957b83" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_606002c3-d68b-4b74-a766-1256348e6a9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_606002c3-d68b-4b74-a766-1256348e6a9a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_606002c3-d68b-4b74-a766-1256348e6a9a" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_606002c3-d68b-4b74-a766-1256348e6a9a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_1305b2db-8a1b-4cde-b139-f22a2b8607ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_606002c3-d68b-4b74-a766-1256348e6a9a" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_1305b2db-8a1b-4cde-b139-f22a2b8607ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_19dc66f5-1254-4ebf-b80a-8f340ebf5aea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_1305b2db-8a1b-4cde-b139-f22a2b8607ce" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_19dc66f5-1254-4ebf-b80a-8f340ebf5aea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_a253a94d-a160-4721-a818-11ef41672604" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_53ebad3d-bb7d-4b5d-832d-38c33c957b83" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_a253a94d-a160-4721-a818-11ef41672604" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a253a94d-a160-4721-a818-11ef41672604_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_a253a94d-a160-4721-a818-11ef41672604" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_a253a94d-a160-4721-a818-11ef41672604_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5b6c0d6e-e36d-469a-b72e-ec4c709c407f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_a253a94d-a160-4721-a818-11ef41672604" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5b6c0d6e-e36d-469a-b72e-ec4c709c407f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_c1cd9334-3c25-4490-8f71-a312d93c093c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5b6c0d6e-e36d-469a-b72e-ec4c709c407f" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_c1cd9334-3c25-4490-8f71-a312d93c093c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_23b38b39-22ec-4805-ac66-f167bd9113f3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5b6c0d6e-e36d-469a-b72e-ec4c709c407f" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_23b38b39-22ec-4805-ac66-f167bd9113f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_220f2c6a-260c-4db7-8410-a459ebb1ad3f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_5b6c0d6e-e36d-469a-b72e-ec4c709c407f" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_220f2c6a-260c-4db7-8410-a459ebb1ad3f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_cc64bdd1-697d-4cc1-ac5e-624292876287" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_53ebad3d-bb7d-4b5d-832d-38c33c957b83" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_cc64bdd1-697d-4cc1-ac5e-624292876287" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_cc64bdd1-697d-4cc1-ac5e-624292876287_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_cc64bdd1-697d-4cc1-ac5e-624292876287" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_cc64bdd1-697d-4cc1-ac5e-624292876287_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_bb629671-cb60-42b0-87ba-50accaec8053" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_cc64bdd1-697d-4cc1-ac5e-624292876287" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_bb629671-cb60-42b0-87ba-50accaec8053" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateSwapMember_a540c6fb-e59a-4eb1-9b80-336a216c999d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestRateSwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_bb629671-cb60-42b0-87ba-50accaec8053" xlink:to="loc_us-gaap_InterestRateSwapMember_a540c6fb-e59a-4eb1-9b80-336a216c999d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignExchangeContractMember_09017c63-ddd2-4c2a-b791-a226d54a7493" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ForeignExchangeContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_bb629671-cb60-42b0-87ba-50accaec8053" xlink:to="loc_us-gaap_ForeignExchangeContractMember_09017c63-ddd2-4c2a-b791-a226d54a7493" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_FuelDerivativeMember_70d195f8-851b-48f1-bd80-20a826d79be9" xlink:href="unfi-20250802.xsd#unfi_FuelDerivativeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_bb629671-cb60-42b0-87ba-50accaec8053" xlink:to="loc_unfi_FuelDerivativeMember_70d195f8-851b-48f1-bd80-20a826d79be9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_d0396524-0028-42e9-b61c-866a06b4ea35" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_53ebad3d-bb7d-4b5d-832d-38c33c957b83" xlink:to="loc_us-gaap_HedgingDesignationAxis_d0396524-0028-42e9-b61c-866a06b4ea35" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_d0396524-0028-42e9-b61c-866a06b4ea35_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_d0396524-0028-42e9-b61c-866a06b4ea35" xlink:to="loc_us-gaap_HedgingDesignationDomain_d0396524-0028-42e9-b61c-866a06b4ea35_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_ace832d1-3546-4a88-bdcb-0c4fe61fee23" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_d0396524-0028-42e9-b61c-866a06b4ea35" xlink:to="loc_us-gaap_HedgingDesignationDomain_ace832d1-3546-4a88-bdcb-0c4fe61fee23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_488d7f1d-1d52-49fd-8a6e-d290fae2e09f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_ace832d1-3546-4a88-bdcb-0c4fe61fee23" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_488d7f1d-1d52-49fd-8a6e-d290fae2e09f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetsCurrent_9a2fdec9-e3fa-4972-b98d-d2b4d5b1b9ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_add221b7-482b-468f-b2a4-a4a1d4c5ff4b" xlink:to="loc_us-gaap_DerivativeAssetsCurrent_9a2fdec9-e3fa-4972-b98d-d2b4d5b1b9ad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilitiesCurrent_e915495b-4fd9-4925-b92a-e87c2d8ba137" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_add221b7-482b-468f-b2a4-a4a1d4c5ff4b" xlink:to="loc_us-gaap_DerivativeLiabilitiesCurrent_e915495b-4fd9-4925-b92a-e87c2d8ba137" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilitiesNoncurrent_cdf5355f-d353-4096-b246-dc1969afea02" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_add221b7-482b-468f-b2a4-a4a1d4c5ff4b" xlink:to="loc_us-gaap_DerivativeLiabilitiesNoncurrent_cdf5355f-d353-4096-b246-dc1969afea02" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetCurrentStatementOfFinancialPositionExtensibleEnumeration_a7494187-8d39-491c-a78d-1848eecb3729" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeAssetCurrentStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_add221b7-482b-468f-b2a4-a4a1d4c5ff4b" xlink:to="loc_us-gaap_DerivativeAssetCurrentStatementOfFinancialPositionExtensibleEnumeration_a7494187-8d39-491c-a78d-1848eecb3729" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityCurrentStatementOfFinancialPositionExtensibleEnumeration_e6df46d6-aff0-4ec0-8026-87f229e6b469" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilityCurrentStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_add221b7-482b-468f-b2a4-a4a1d4c5ff4b" xlink:to="loc_us-gaap_DerivativeLiabilityCurrentStatementOfFinancialPositionExtensibleEnumeration_e6df46d6-aff0-4ec0-8026-87f229e6b469" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityNoncurrentStatementOfFinancialPositionExtensibleEnumeration_ff771ae6-df7a-4311-888c-9df86b7e4b70" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLiabilityNoncurrentStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_add221b7-482b-468f-b2a4-a4a1d4c5ff4b" xlink:to="loc_us-gaap_DerivativeLiabilityNoncurrentStatementOfFinancialPositionExtensibleEnumeration_ff771ae6-df7a-4311-888c-9df86b7e4b70" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/FAIRVALUEMEASUREMENTSOFFINANCIALINSTRUMENTSFairValueEstimatesDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#FAIRVALUEMEASUREMENTSOFFINANCIALINSTRUMENTSFairValueEstimatesDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/FAIRVALUEMEASUREMENTSOFFINANCIALINSTRUMENTSFairValueEstimatesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_124332b6-5aec-4460-a89e-3f842fc1cf7f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_a1d67dda-a76a-4f07-9bb8-cf1e563e1d34" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_124332b6-5aec-4460-a89e-3f842fc1cf7f" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_a1d67dda-a76a-4f07-9bb8-cf1e563e1d34" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_33d6ef88-ee30-47f7-9461-b8d346bd988e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_a1d67dda-a76a-4f07-9bb8-cf1e563e1d34" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_33d6ef88-ee30-47f7-9461-b8d346bd988e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_33d6ef88-ee30-47f7-9461-b8d346bd988e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_33d6ef88-ee30-47f7-9461-b8d346bd988e" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_33d6ef88-ee30-47f7-9461-b8d346bd988e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_83e0729e-3ac1-493f-b68c-4b6bb0f968ae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_33d6ef88-ee30-47f7-9461-b8d346bd988e" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_83e0729e-3ac1-493f-b68c-4b6bb0f968ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f20b75d4-6d44-4f76-85db-cc5dd9d42999" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_83e0729e-3ac1-493f-b68c-4b6bb0f968ae" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f20b75d4-6d44-4f76-85db-cc5dd9d42999" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_3f8b7f4b-c0cf-4fe1-a9e9-833527460218" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f20b75d4-6d44-4f76-85db-cc5dd9d42999" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_3f8b7f4b-c0cf-4fe1-a9e9-833527460218" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_61e186d9-b946-4674-8820-f4a9bca8e13a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_f20b75d4-6d44-4f76-85db-cc5dd9d42999" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_61e186d9-b946-4674-8820-f4a9bca8e13a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableFairValueDisclosure_600f561d-4566-427c-8e28-0c770908cfb6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NotesReceivableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_124332b6-5aec-4460-a89e-3f842fc1cf7f" xlink:to="loc_us-gaap_NotesReceivableFairValueDisclosure_600f561d-4566-427c-8e28-0c770908cfb6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_0ecb06f0-6fc9-4875-a836-25ca2e50199e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_124332b6-5aec-4460-a89e-3f842fc1cf7f" xlink:to="loc_us-gaap_LongTermDebtFairValue_0ecb06f0-6fc9-4875-a836-25ca2e50199e" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/DERIVATIVESOutstandingSwapContractsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#DERIVATIVESOutstandingSwapContractsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/DERIVATIVESOutstandingSwapContractsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_114a3a02-6a45-45f9-a641-f29800d5e103" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_63bfea0b-966b-4df6-b3f8-ee8596cb2e8a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_114a3a02-6a45-45f9-a641-f29800d5e103" xlink:to="loc_us-gaap_DerivativeTable_63bfea0b-966b-4df6-b3f8-ee8596cb2e8a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_740ac6a3-54d4-4c5f-b2e9-0a12de4155af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_63bfea0b-966b-4df6-b3f8-ee8596cb2e8a" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_740ac6a3-54d4-4c5f-b2e9-0a12de4155af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_740ac6a3-54d4-4c5f-b2e9-0a12de4155af_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_740ac6a3-54d4-4c5f-b2e9-0a12de4155af" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_740ac6a3-54d4-4c5f-b2e9-0a12de4155af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_740ac6a3-54d4-4c5f-b2e9-0a12de4155af" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueOctober2220251Member_0723c92c-835a-46c1-9d3f-e9822a787999" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueOctober2220251Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueOctober2220251Member_0723c92c-835a-46c1-9d3f-e9822a787999" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueOctober2220252Member_4c6d75ae-42e6-45ae-908d-7a80ec4c21c5" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueOctober2220252Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueOctober2220252Member_4c6d75ae-42e6-45ae-908d-7a80ec4c21c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueOctober2220253Member_a39d6cca-5aca-4888-a049-e97cd7b72de3" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueOctober2220253Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueOctober2220253Member_a39d6cca-5aca-4888-a049-e97cd7b72de3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueOctober2220254Member_518b574a-a915-408b-a318-5e7811f5460e" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueOctober2220254Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueOctober2220254Member_518b574a-a915-408b-a318-5e7811f5460e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueJune320271Member_68204f08-96e4-4431-8b5c-1ce6d4bb40b0" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueJune320271Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueJune320271Member_68204f08-96e4-4431-8b5c-1ce6d4bb40b0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueJune320272Member_d14ad3c3-11cd-42b4-a995-d58f0e578871" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueJune320272Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueJune320272Member_d14ad3c3-11cd-42b4-a995-d58f0e578871" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueJune3020281Member_0009db37-5cbf-4ed4-853e-f6eb4e129932" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueJune3020281Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueJune3020281Member_0009db37-5cbf-4ed4-853e-f6eb4e129932" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueJune3020282Member_024a7632-4e5a-4015-8041-2be46c49ed46" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueJune3020282Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueJune3020282Member_024a7632-4e5a-4015-8041-2be46c49ed46" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueOctober302026Member_79c22394-db76-4284-8021-9acd55173235" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueOctober302026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueOctober302026Member_79c22394-db76-4284-8021-9acd55173235" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueOctober3020262Member_531e66ff-75c6-4b2a-b79c-42c1174ced68" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueOctober3020262Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueOctober3020262Member_531e66ff-75c6-4b2a-b79c-42c1174ced68" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InterestRateSwapDueOctober3020263Member_fd80de29-df3b-4d62-8ae6-94e673badeeb" xlink:href="unfi-20250802.xsd#unfi_InterestRateSwapDueOctober3020263Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_642a181e-f2bd-4add-8f5d-dc60ce1dd9c5" xlink:to="loc_unfi_InterestRateSwapDueOctober3020263Member_fd80de29-df3b-4d62-8ae6-94e673badeeb" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_30ce5ef1-abe8-404d-a3e9-18439f1c95fc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_114a3a02-6a45-45f9-a641-f29800d5e103" xlink:to="loc_us-gaap_DerivativeNotionalAmount_30ce5ef1-abe8-404d-a3e9-18439f1c95fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeForwardInterestRate_c1fda35d-d74b-4978-a202-d9dc0cc8bcb4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeForwardInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_114a3a02-6a45-45f9-a641-f29800d5e103" xlink:to="loc_us-gaap_DerivativeForwardInterestRate_c1fda35d-d74b-4978-a202-d9dc0cc8bcb4" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LONGTERMDEBTScheduleofLongtermDebtDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LONGTERMDEBTScheduleofLongtermDebtDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LONGTERMDEBTScheduleofLongtermDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_99314cfb-46d7-48f4-9ae7-a3451deaec6b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_17441d3b-a933-4b7b-9f2f-e935ec6de1fb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_99314cfb-46d7-48f4-9ae7-a3451deaec6b" xlink:to="loc_us-gaap_DebtInstrumentTable_17441d3b-a933-4b7b-9f2f-e935ec6de1fb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_56e8b80c-64b5-4561-a388-ef971528e445" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_17441d3b-a933-4b7b-9f2f-e935ec6de1fb" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_56e8b80c-64b5-4561-a388-ef971528e445" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_56e8b80c-64b5-4561-a388-ef971528e445_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_56e8b80c-64b5-4561-a388-ef971528e445" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_56e8b80c-64b5-4561-a388-ef971528e445_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_1948e7ca-3ab5-4037-b198-cd7712f41f20" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_56e8b80c-64b5-4561-a388-ef971528e445" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_1948e7ca-3ab5-4037-b198-cd7712f41f20" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_b69e8ed0-7cf8-4c4b-997a-a0026ca0dd30" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_1948e7ca-3ab5-4037-b198-cd7712f41f20" xlink:to="loc_us-gaap_SecuredDebtMember_b69e8ed0-7cf8-4c4b-997a-a0026ca0dd30" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_2319276a-c3e3-42e3-b1bc-e3cc59b49adf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_1948e7ca-3ab5-4037-b198-cd7712f41f20" xlink:to="loc_us-gaap_SeniorNotesMember_2319276a-c3e3-42e3-b1bc-e3cc59b49adf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_3c115922-2faa-43bd-8dd5-099e8dee6db6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_17441d3b-a933-4b7b-9f2f-e935ec6de1fb" xlink:to="loc_us-gaap_DebtInstrumentAxis_3c115922-2faa-43bd-8dd5-099e8dee6db6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_3c115922-2faa-43bd-8dd5-099e8dee6db6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_3c115922-2faa-43bd-8dd5-099e8dee6db6" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_3c115922-2faa-43bd-8dd5-099e8dee6db6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_41bca833-7f38-4a14-8068-ea2f38654b62" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_3c115922-2faa-43bd-8dd5-099e8dee6db6" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_41bca833-7f38-4a14-8068-ea2f38654b62" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_TermLoanFacilityMember_f1e4d9d5-83fb-4df8-b652-509ada878924" xlink:href="unfi-20250802.xsd#unfi_TermLoanFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41bca833-7f38-4a14-8068-ea2f38654b62" xlink:to="loc_unfi_TermLoanFacilityMember_f1e4d9d5-83fb-4df8-b652-509ada878924" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ABLCreditFacilityMember_20b37cdb-20dc-4f77-b554-eb7c93be147f" xlink:href="unfi-20250802.xsd#unfi_ABLCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41bca833-7f38-4a14-8068-ea2f38654b62" xlink:to="loc_unfi_ABLCreditFacilityMember_20b37cdb-20dc-4f77-b554-eb7c93be147f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_SeniorNotesDueOctober20286750Member_4245a4b9-853a-401f-95d9-ff9ed02c062f" xlink:href="unfi-20250802.xsd#unfi_SeniorNotesDueOctober20286750Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41bca833-7f38-4a14-8068-ea2f38654b62" xlink:to="loc_unfi_SeniorNotesDueOctober20286750Member_4245a4b9-853a-401f-95d9-ff9ed02c062f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_OtherSecuredDebtsMember_2faf24c1-ff2c-4e20-a079-b74e794bfd70" xlink:href="unfi-20250802.xsd#unfi_OtherSecuredDebtsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_41bca833-7f38-4a14-8068-ea2f38654b62" xlink:to="loc_unfi_OtherSecuredDebtsMember_2faf24c1-ff2c-4e20-a079-b74e794bfd70" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_11f48bf6-fbb8-4aaa-8a6a-966e4ce63352" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_99314cfb-46d7-48f4-9ae7-a3451deaec6b" xlink:to="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_11f48bf6-fbb8-4aaa-8a6a-966e4ce63352" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_97cff98b-09d7-4887-8f73-2e7edf6ba4b1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_99314cfb-46d7-48f4-9ae7-a3451deaec6b" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_97cff98b-09d7-4887-8f73-2e7edf6ba4b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_fdcd7917-04a6-40e1-99ec-f26baf7ef9d5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_99314cfb-46d7-48f4-9ae7-a3451deaec6b" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_fdcd7917-04a6-40e1-99ec-f26baf7ef9d5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_62ea0c40-d9b0-42ef-b97b-6ce4712958c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_99314cfb-46d7-48f4-9ae7-a3451deaec6b" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_62ea0c40-d9b0-42ef-b97b-6ce4712958c7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_3f5cb6ee-f1c2-4089-88ab-11cd57bad3d7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_99314cfb-46d7-48f4-9ae7-a3451deaec6b" xlink:to="loc_us-gaap_LongTermDebt_3f5cb6ee-f1c2-4089-88ab-11cd57bad3d7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_24e5781c-3fa2-485f-bc71-50ca7405ab13" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_99314cfb-46d7-48f4-9ae7-a3451deaec6b" xlink:to="loc_us-gaap_LongTermDebtCurrent_24e5781c-3fa2-485f-bc71-50ca7405ab13" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_00c71183-1a98-48a8-a535-37b14dfcbd0f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_99314cfb-46d7-48f4-9ae7-a3451deaec6b" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_00c71183-1a98-48a8-a535-37b14dfcbd0f" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LONGTERMDEBTTermLoanFacilityDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LONGTERMDEBTTermLoanFacilityDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LONGTERMDEBTTermLoanFacilityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_a2f47090-18ef-4d6f-b36a-29eff7ca1226" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_us-gaap_DebtInstrumentTable_a2f47090-18ef-4d6f-b36a-29eff7ca1226" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_824443a8-3fb0-4016-974f-11ee8b14ac89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a2f47090-18ef-4d6f-b36a-29eff7ca1226" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_824443a8-3fb0-4016-974f-11ee8b14ac89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_824443a8-3fb0-4016-974f-11ee8b14ac89_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_824443a8-3fb0-4016-974f-11ee8b14ac89" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_824443a8-3fb0-4016-974f-11ee8b14ac89_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_dec10912-5eb8-49e1-85f2-65013c5e1e60" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_824443a8-3fb0-4016-974f-11ee8b14ac89" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_dec10912-5eb8-49e1-85f2-65013c5e1e60" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_9859e796-fc7d-4629-be62-bdea60ed1f2b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_dec10912-5eb8-49e1-85f2-65013c5e1e60" xlink:to="loc_us-gaap_SecuredDebtMember_9859e796-fc7d-4629-be62-bdea60ed1f2b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_07291cb6-3395-419f-8730-1dfca62d30bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a2f47090-18ef-4d6f-b36a-29eff7ca1226" xlink:to="loc_us-gaap_DebtInstrumentAxis_07291cb6-3395-419f-8730-1dfca62d30bf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_07291cb6-3395-419f-8730-1dfca62d30bf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_07291cb6-3395-419f-8730-1dfca62d30bf" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_07291cb6-3395-419f-8730-1dfca62d30bf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_31263484-b889-4d5d-92d8-093b4b776763" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_07291cb6-3395-419f-8730-1dfca62d30bf" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_31263484-b889-4d5d-92d8-093b4b776763" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_TermLoanFacilityMember_edfc6543-03a0-4d00-a328-29ce77a31e9c" xlink:href="unfi-20250802.xsd#unfi_TermLoanFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_31263484-b889-4d5d-92d8-093b4b776763" xlink:to="loc_unfi_TermLoanFacilityMember_edfc6543-03a0-4d00-a328-29ce77a31e9c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_298a966d-d5c0-4862-ac6f-e059c9cba96d" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a2f47090-18ef-4d6f-b36a-29eff7ca1226" xlink:to="loc_srt_RangeAxis_298a966d-d5c0-4862-ac6f-e059c9cba96d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_298a966d-d5c0-4862-ac6f-e059c9cba96d_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_298a966d-d5c0-4862-ac6f-e059c9cba96d" xlink:to="loc_srt_RangeMember_298a966d-d5c0-4862-ac6f-e059c9cba96d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e6d588fb-a2a3-46ce-8cd4-4ead76d4a8dc" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_298a966d-d5c0-4862-ac6f-e059c9cba96d" xlink:to="loc_srt_RangeMember_e6d588fb-a2a3-46ce-8cd4-4ead76d4a8dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_d1b4c56e-27c2-4e2d-a96f-35b1ba0cb9b6" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_e6d588fb-a2a3-46ce-8cd4-4ead76d4a8dc" xlink:to="loc_srt_MaximumMember_d1b4c56e-27c2-4e2d-a96f-35b1ba0cb9b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_684bfcfd-ec0b-4cde-ba06-ad712a896d5a" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_e6d588fb-a2a3-46ce-8cd4-4ead76d4a8dc" xlink:to="loc_srt_MinimumMember_684bfcfd-ec0b-4cde-ba06-ad712a896d5a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_a8e61540-56bc-49bd-9d09-46e3f15a8703" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a2f47090-18ef-4d6f-b36a-29eff7ca1226" xlink:to="loc_us-gaap_VariableRateAxis_a8e61540-56bc-49bd-9d09-46e3f15a8703" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_a8e61540-56bc-49bd-9d09-46e3f15a8703_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_a8e61540-56bc-49bd-9d09-46e3f15a8703" xlink:to="loc_us-gaap_VariableRateDomain_a8e61540-56bc-49bd-9d09-46e3f15a8703_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_eb1854a6-4c7d-406f-8428-02afc178bd47" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_a8e61540-56bc-49bd-9d09-46e3f15a8703" xlink:to="loc_us-gaap_VariableRateDomain_eb1854a6-4c7d-406f-8428-02afc178bd47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_4b1f65e9-18b2-488b-a26a-4d689631e9c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_eb1854a6-4c7d-406f-8428-02afc178bd47" xlink:to="loc_us-gaap_BaseRateMember_4b1f65e9-18b2-488b-a26a-4d689631e9c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_4b50eaea-ebcd-46a1-a877-aa407c94f3bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_eb1854a6-4c7d-406f-8428-02afc178bd47" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_4b50eaea-ebcd-46a1-a877-aa407c94f3bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtinguishmentOfDebtAxis_c68053fc-b75b-4e2e-bd23-09f77e358892" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ExtinguishmentOfDebtAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a2f47090-18ef-4d6f-b36a-29eff7ca1226" xlink:to="loc_us-gaap_ExtinguishmentOfDebtAxis_c68053fc-b75b-4e2e-bd23-09f77e358892" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtinguishmentOfDebtTypeDomain_c68053fc-b75b-4e2e-bd23-09f77e358892_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ExtinguishmentOfDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ExtinguishmentOfDebtAxis_c68053fc-b75b-4e2e-bd23-09f77e358892" xlink:to="loc_us-gaap_ExtinguishmentOfDebtTypeDomain_c68053fc-b75b-4e2e-bd23-09f77e358892_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtinguishmentOfDebtTypeDomain_63c54244-a361-4154-a5a3-ec3915f91e7b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ExtinguishmentOfDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ExtinguishmentOfDebtAxis_c68053fc-b75b-4e2e-bd23-09f77e358892" xlink:to="loc_us-gaap_ExtinguishmentOfDebtTypeDomain_63c54244-a361-4154-a5a3-ec3915f91e7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_acafa471-5bee-4a24-9f83-0571d6986ee4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ExtinguishmentOfDebtTypeDomain_63c54244-a361-4154-a5a3-ec3915f91e7b" xlink:to="loc_us-gaap_SecuredDebtMember_acafa471-5bee-4a24-9f83-0571d6986ee4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MaturityComponentAxis_8d896045-0751-428d-9801-fa82629e7ef0" xlink:href="unfi-20250802.xsd#unfi_MaturityComponentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_a2f47090-18ef-4d6f-b36a-29eff7ca1226" xlink:to="loc_unfi_MaturityComponentAxis_8d896045-0751-428d-9801-fa82629e7ef0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MaturityComponentDomain_8d896045-0751-428d-9801-fa82629e7ef0_default" xlink:href="unfi-20250802.xsd#unfi_MaturityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_unfi_MaturityComponentAxis_8d896045-0751-428d-9801-fa82629e7ef0" xlink:to="loc_unfi_MaturityComponentDomain_8d896045-0751-428d-9801-fa82629e7ef0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MaturityComponentDomain_e8032983-c8ec-4f94-8710-b7453c9fe0f8" xlink:href="unfi-20250802.xsd#unfi_MaturityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_unfi_MaturityComponentAxis_8d896045-0751-428d-9801-fa82629e7ef0" xlink:to="loc_unfi_MaturityComponentDomain_e8032983-c8ec-4f94-8710-b7453c9fe0f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_SpringingMaturityComponentTwoMember_bb23b334-1b46-4a53-8a14-d764d550356e" xlink:href="unfi-20250802.xsd#unfi_SpringingMaturityComponentTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_MaturityComponentDomain_e8032983-c8ec-4f94-8710-b7453c9fe0f8" xlink:to="loc_unfi_SpringingMaturityComponentTwoMember_bb23b334-1b46-4a53-8a14-d764d550356e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_2369ffa1-cb84-4cd1-a831-fcc90ce02e2d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_2369ffa1-cb84-4cd1-a831-fcc90ce02e2d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DebtInstrumentCovenantSpringingMaturityCriteriaNumberOfDaysPriorToMaturityOfSeniorNotesIfCircumstancesMet_deb5fde5-e2ee-4f03-89b7-ab85c2747346" xlink:href="unfi-20250802.xsd#unfi_DebtInstrumentCovenantSpringingMaturityCriteriaNumberOfDaysPriorToMaturityOfSeniorNotesIfCircumstancesMet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_unfi_DebtInstrumentCovenantSpringingMaturityCriteriaNumberOfDaysPriorToMaturityOfSeniorNotesIfCircumstancesMet_deb5fde5-e2ee-4f03-89b7-ab85c2747346" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DebtInstrumentCovenantSpringingMaturityCriteriaMinimumPrincipalAmountOutstanding_8a0423b8-b83a-4505-884e-d3aceeb3211c" xlink:href="unfi-20250802.xsd#unfi_DebtInstrumentCovenantSpringingMaturityCriteriaMinimumPrincipalAmountOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_unfi_DebtInstrumentCovenantSpringingMaturityCriteriaMinimumPrincipalAmountOutstanding_8a0423b8-b83a-4505-884e-d3aceeb3211c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_2b2d974a-7236-4ce8-89cd-23f01c4db5bf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_2b2d974a-7236-4ce8-89cd-23f01c4db5bf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_LineofCreditAdditionalBorrowingCapacity_d974c316-d403-4252-980c-50e0aa7dda02" xlink:href="unfi-20250802.xsd#unfi_LineofCreditAdditionalBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_unfi_LineofCreditAdditionalBorrowingCapacity_d974c316-d403-4252-980c-50e0aa7dda02" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DebtInstrumentGuaranteesExceptionCarryingValueofOwnedRealProperty_e295578e-ebf0-4868-b2fb-75564f8d63ed" xlink:href="unfi-20250802.xsd#unfi_DebtInstrumentGuaranteesExceptionCarryingValueofOwnedRealProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_unfi_DebtInstrumentGuaranteesExceptionCarryingValueofOwnedRealProperty_e295578e-ebf0-4868-b2fb-75564f8d63ed" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCollateralAmount_e829fee2-cd04-4311-8f83-5459bd102170" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentCollateralAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_us-gaap_DebtInstrumentCollateralAmount_e829fee2-cd04-4311-8f83-5459bd102170" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DebtInstrumentDebtPrepaymentPeriod_3fcb705d-27bc-463f-a3dd-ba59d80bffc6" xlink:href="unfi-20250802.xsd#unfi_DebtInstrumentDebtPrepaymentPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_unfi_DebtInstrumentDebtPrepaymentPeriod_3fcb705d-27bc-463f-a3dd-ba59d80bffc6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfSecuredDebt_ffe642a1-4f45-4e67-8c0c-b9d6517c1083" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RepaymentsOfSecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_us-gaap_RepaymentsOfSecuredDebt_ffe642a1-4f45-4e67-8c0c-b9d6517c1083" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_f290a0f2-050f-4c88-ad5a-03907a38b5c8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_f290a0f2-050f-4c88-ad5a-03907a38b5c8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_VoluntaryRepaymentsofDebt_fced0073-e47f-4753-af1d-6cbc92175aa2" xlink:href="unfi-20250802.xsd#unfi_VoluntaryRepaymentsofDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_4154dc84-7fec-49bf-aa22-c80e3943585b" xlink:to="loc_unfi_VoluntaryRepaymentsofDebt_fced0073-e47f-4753-af1d-6cbc92175aa2" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LONGTERMDEBTABLCreditFacilityDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LONGTERMDEBTABLCreditFacilityDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LONGTERMDEBTABLCreditFacilityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_3dd87a7d-a36d-40f7-ad1d-2d203bcc0653" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_bb281d6d-0cd3-4a25-b193-b6c18531e66b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3dd87a7d-a36d-40f7-ad1d-2d203bcc0653" xlink:to="loc_us-gaap_DebtInstrumentTable_bb281d6d-0cd3-4a25-b193-b6c18531e66b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_2b7051fa-1781-4ff8-ae87-e57d0791318a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_bb281d6d-0cd3-4a25-b193-b6c18531e66b" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_2b7051fa-1781-4ff8-ae87-e57d0791318a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2b7051fa-1781-4ff8-ae87-e57d0791318a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2b7051fa-1781-4ff8-ae87-e57d0791318a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2b7051fa-1781-4ff8-ae87-e57d0791318a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_d8626176-1a73-4519-b6a8-990877c90323" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2b7051fa-1781-4ff8-ae87-e57d0791318a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_d8626176-1a73-4519-b6a8-990877c90323" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_3cd0deab-3831-48a7-abd0-481f631cabc9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_d8626176-1a73-4519-b6a8-990877c90323" xlink:to="loc_us-gaap_LineOfCreditMember_3cd0deab-3831-48a7-abd0-481f631cabc9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_7b7818c9-bfac-4150-b492-524f450af150" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_bb281d6d-0cd3-4a25-b193-b6c18531e66b" xlink:to="loc_us-gaap_CreditFacilityAxis_7b7818c9-bfac-4150-b492-524f450af150" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_7b7818c9-bfac-4150-b492-524f450af150_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_7b7818c9-bfac-4150-b492-524f450af150" xlink:to="loc_us-gaap_CreditFacilityDomain_7b7818c9-bfac-4150-b492-524f450af150_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_52815270-df03-4332-83ae-6b5b3be2024a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_7b7818c9-bfac-4150-b492-524f450af150" xlink:to="loc_us-gaap_CreditFacilityDomain_52815270-df03-4332-83ae-6b5b3be2024a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_8dfb4e3d-1f14-4bf5-8f5d-f3ec41498866" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_52815270-df03-4332-83ae-6b5b3be2024a" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_8dfb4e3d-1f14-4bf5-8f5d-f3ec41498866" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_043dfbe6-aedd-4b3a-b4f9-c1a17732d35b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_bb281d6d-0cd3-4a25-b193-b6c18531e66b" xlink:to="loc_us-gaap_DebtInstrumentAxis_043dfbe6-aedd-4b3a-b4f9-c1a17732d35b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_043dfbe6-aedd-4b3a-b4f9-c1a17732d35b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_043dfbe6-aedd-4b3a-b4f9-c1a17732d35b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_043dfbe6-aedd-4b3a-b4f9-c1a17732d35b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_b9fd1a98-2fe4-4780-8fbf-2a8e38d688f8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_043dfbe6-aedd-4b3a-b4f9-c1a17732d35b" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_b9fd1a98-2fe4-4780-8fbf-2a8e38d688f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ABLCreditFacilityMember_7e80a007-99e0-4517-9002-cdc34487f788" xlink:href="unfi-20250802.xsd#unfi_ABLCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_b9fd1a98-2fe4-4780-8fbf-2a8e38d688f8" xlink:to="loc_unfi_ABLCreditFacilityMember_7e80a007-99e0-4517-9002-cdc34487f788" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ABLCreditFacilityRevolverLoansMember_710d90db-369c-4b63-8652-8a307bd7d7ad" xlink:href="unfi-20250802.xsd#unfi_ABLCreditFacilityRevolverLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_ABLCreditFacilityMember_7e80a007-99e0-4517-9002-cdc34487f788" xlink:to="loc_unfi_ABLCreditFacilityRevolverLoansMember_710d90db-369c-4b63-8652-8a307bd7d7ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ABLCreditFacilityFILOTrancheMember_462c2192-58f1-4991-901a-bfbf7dc47c4a" xlink:href="unfi-20250802.xsd#unfi_ABLCreditFacilityFILOTrancheMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_ABLCreditFacilityMember_7e80a007-99e0-4517-9002-cdc34487f788" xlink:to="loc_unfi_ABLCreditFacilityFILOTrancheMember_462c2192-58f1-4991-901a-bfbf7dc47c4a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_36170dfa-73ea-46f5-b353-e5e8adabe70e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3dd87a7d-a36d-40f7-ad1d-2d203bcc0653" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_36170dfa-73ea-46f5-b353-e5e8adabe70e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_LineOfCreditFacilityMaximumBorrowingCapacityOptionalIncrease_ef622041-02e4-45ca-9797-75aaf83a0a79" xlink:href="unfi-20250802.xsd#unfi_LineOfCreditFacilityMaximumBorrowingCapacityOptionalIncrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3dd87a7d-a36d-40f7-ad1d-2d203bcc0653" xlink:to="loc_unfi_LineOfCreditFacilityMaximumBorrowingCapacityOptionalIncrease_ef622041-02e4-45ca-9797-75aaf83a0a79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_7df86a78-d7fb-4975-86b5-ae82bfb8947d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3dd87a7d-a36d-40f7-ad1d-2d203bcc0653" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_7df86a78-d7fb-4975-86b5-ae82bfb8947d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_LineOfCreditFacilityBorrowingCapacityReserves_f7bf7897-647b-4590-966d-b0bdb337de95" xlink:href="unfi-20250802.xsd#unfi_LineOfCreditFacilityBorrowingCapacityReserves"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_3dd87a7d-a36d-40f7-ad1d-2d203bcc0653" xlink:to="loc_unfi_LineOfCreditFacilityBorrowingCapacityReserves_f7bf7897-647b-4590-966d-b0bdb337de95" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LONGTERMDEBTApplicableMarginsandFeesDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LONGTERMDEBTApplicableMarginsandFeesDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LONGTERMDEBTApplicableMarginsandFeesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_f1e3f7db-34cc-46e9-9eae-40ef88174d47" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_014c31da-9410-48af-840d-74e24077c1a1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_f1e3f7db-34cc-46e9-9eae-40ef88174d47" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_014c31da-9410-48af-840d-74e24077c1a1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_8550dbfc-6ace-4eb3-90da-21c02553d4ab" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_014c31da-9410-48af-840d-74e24077c1a1" xlink:to="loc_srt_RangeAxis_8550dbfc-6ace-4eb3-90da-21c02553d4ab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8550dbfc-6ace-4eb3-90da-21c02553d4ab_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_8550dbfc-6ace-4eb3-90da-21c02553d4ab" xlink:to="loc_srt_RangeMember_8550dbfc-6ace-4eb3-90da-21c02553d4ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c573c830-ce90-4cb4-9331-754a0713c0f9" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_8550dbfc-6ace-4eb3-90da-21c02553d4ab" xlink:to="loc_srt_RangeMember_c573c830-ce90-4cb4-9331-754a0713c0f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_87ac74ef-3d9c-4b9e-8599-8409e5addd0c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c573c830-ce90-4cb4-9331-754a0713c0f9" xlink:to="loc_srt_MinimumMember_87ac74ef-3d9c-4b9e-8599-8409e5addd0c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_5bc046f3-43b8-4be0-9015-8522e294ec7f" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c573c830-ce90-4cb4-9331-754a0713c0f9" xlink:to="loc_srt_MaximumMember_5bc046f3-43b8-4be0-9015-8522e294ec7f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_f14b7f26-bd94-4b43-a67c-7db7c46d3f04" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_014c31da-9410-48af-840d-74e24077c1a1" xlink:to="loc_us-gaap_CreditFacilityAxis_f14b7f26-bd94-4b43-a67c-7db7c46d3f04" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_f14b7f26-bd94-4b43-a67c-7db7c46d3f04_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_f14b7f26-bd94-4b43-a67c-7db7c46d3f04" xlink:to="loc_us-gaap_CreditFacilityDomain_f14b7f26-bd94-4b43-a67c-7db7c46d3f04_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_3819f0c8-420d-4017-bc73-c3448976efa3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_f14b7f26-bd94-4b43-a67c-7db7c46d3f04" xlink:to="loc_us-gaap_CreditFacilityDomain_3819f0c8-420d-4017-bc73-c3448976efa3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_abe961a1-dd69-4b43-80b8-d9dfad288f5e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_3819f0c8-420d-4017-bc73-c3448976efa3" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_abe961a1-dd69-4b43-80b8-d9dfad288f5e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_adfacfaf-064c-46a0-876a-53a6c8bb9f69" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_3819f0c8-420d-4017-bc73-c3448976efa3" xlink:to="loc_us-gaap_LetterOfCreditMember_adfacfaf-064c-46a0-876a-53a6c8bb9f69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_99b4faf0-9092-4937-8d1c-876c591bb6ad" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_014c31da-9410-48af-840d-74e24077c1a1" xlink:to="loc_us-gaap_DebtInstrumentAxis_99b4faf0-9092-4937-8d1c-876c591bb6ad" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_99b4faf0-9092-4937-8d1c-876c591bb6ad_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_99b4faf0-9092-4937-8d1c-876c591bb6ad" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_99b4faf0-9092-4937-8d1c-876c591bb6ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_c7bdff8a-2bee-4683-9f43-28fbd88f3b5c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_99b4faf0-9092-4937-8d1c-876c591bb6ad" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_c7bdff8a-2bee-4683-9f43-28fbd88f3b5c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ABLCreditFacilityMember_350fd6cb-4b67-4757-a135-80ff9b0335f2" xlink:href="unfi-20250802.xsd#unfi_ABLCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_c7bdff8a-2bee-4683-9f43-28fbd88f3b5c" xlink:to="loc_unfi_ABLCreditFacilityMember_350fd6cb-4b67-4757-a135-80ff9b0335f2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ABLCreditFacilityFILOTrancheMember_73ed681d-f5e0-43c2-8a80-9846c398324e" xlink:href="unfi-20250802.xsd#unfi_ABLCreditFacilityFILOTrancheMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_ABLCreditFacilityMember_350fd6cb-4b67-4757-a135-80ff9b0335f2" xlink:to="loc_unfi_ABLCreditFacilityFILOTrancheMember_73ed681d-f5e0-43c2-8a80-9846c398324e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_2eb48ced-31cf-422d-a399-e1625742d923" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_014c31da-9410-48af-840d-74e24077c1a1" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_2eb48ced-31cf-422d-a399-e1625742d923" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2eb48ced-31cf-422d-a399-e1625742d923_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2eb48ced-31cf-422d-a399-e1625742d923" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2eb48ced-31cf-422d-a399-e1625742d923_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_b064efb4-4bbc-414d-8631-4f57a7eaed39" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_2eb48ced-31cf-422d-a399-e1625742d923" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_b064efb4-4bbc-414d-8631-4f57a7eaed39" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_d3be6a00-d6de-4f6e-9d17-a99c06aff97b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b064efb4-4bbc-414d-8631-4f57a7eaed39" xlink:to="loc_us-gaap_LineOfCreditMember_d3be6a00-d6de-4f6e-9d17-a99c06aff97b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_42824653-b1fd-4876-b431-1adfa3cd5692" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_014c31da-9410-48af-840d-74e24077c1a1" xlink:to="loc_us-gaap_VariableRateAxis_42824653-b1fd-4876-b431-1adfa3cd5692" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_42824653-b1fd-4876-b431-1adfa3cd5692_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_42824653-b1fd-4876-b431-1adfa3cd5692" xlink:to="loc_us-gaap_VariableRateDomain_42824653-b1fd-4876-b431-1adfa3cd5692_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_e73b213f-44bf-45b6-995d-da1332fdea76" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_42824653-b1fd-4876-b431-1adfa3cd5692" xlink:to="loc_us-gaap_VariableRateDomain_e73b213f-44bf-45b6-995d-da1332fdea76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_9814be6e-5b07-4c55-8d13-38670ac7b93d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_e73b213f-44bf-45b6-995d-da1332fdea76" xlink:to="loc_us-gaap_BaseRateMember_9814be6e-5b07-4c55-8d13-38670ac7b93d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_SecuredOvernightFinancingRateSOFRAndBankersAcceptanceRateMember_fc86c125-d722-433b-b6da-ac5a54d6d1e4" xlink:href="unfi-20250802.xsd#unfi_SecuredOvernightFinancingRateSOFRAndBankersAcceptanceRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_e73b213f-44bf-45b6-995d-da1332fdea76" xlink:to="loc_unfi_SecuredOvernightFinancingRateSOFRAndBankersAcceptanceRateMember_fc86c125-d722-433b-b6da-ac5a54d6d1e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_e1982b72-297e-4881-9151-ed94764d40f0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SecuredOvernightFinancingRateSofrMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_e73b213f-44bf-45b6-995d-da1332fdea76" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrMember_e1982b72-297e-4881-9151-ed94764d40f0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_f2e1b43f-4600-4977-a592-bbffab04e68b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_f1e3f7db-34cc-46e9-9eae-40ef88174d47" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_f2e1b43f-4600-4977-a592-bbffab04e68b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_d4e58f6a-633a-4573-a5c3-631c5da53e71" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_f1e3f7db-34cc-46e9-9eae-40ef88174d47" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_d4e58f6a-633a-4573-a5c3-631c5da53e71" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_b3ff30de-3a20-4eef-b5b7-b2c3d2c08aaf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_f1e3f7db-34cc-46e9-9eae-40ef88174d47" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_b3ff30de-3a20-4eef-b5b7-b2c3d2c08aaf" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LONGTERMDEBTBalanceSheetAssetsSecuringOutstandingObligationsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LONGTERMDEBTBalanceSheetAssetsSecuringOutstandingObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LONGTERMDEBTBalanceSheetAssetsSecuringOutstandingObligationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_bc9da3c6-b807-4148-9a72-4e1b0cd06be9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_b51dfc9a-5ef3-49a2-9f38-254861a88cfa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_bc9da3c6-b807-4148-9a72-4e1b0cd06be9" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_b51dfc9a-5ef3-49a2-9f38-254861a88cfa" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_3337d7ec-dca7-47a2-8edf-1a25425f8b23" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_b51dfc9a-5ef3-49a2-9f38-254861a88cfa" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_3337d7ec-dca7-47a2-8edf-1a25425f8b23" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_3337d7ec-dca7-47a2-8edf-1a25425f8b23_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_3337d7ec-dca7-47a2-8edf-1a25425f8b23" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_3337d7ec-dca7-47a2-8edf-1a25425f8b23_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_6d248e3a-9574-484d-be8e-da7ccc90776f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_3337d7ec-dca7-47a2-8edf-1a25425f8b23" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_6d248e3a-9574-484d-be8e-da7ccc90776f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_c33916fd-badf-4168-95e7-ebc15ccbae8d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_6d248e3a-9574-484d-be8e-da7ccc90776f" xlink:to="loc_us-gaap_LineOfCreditMember_c33916fd-badf-4168-95e7-ebc15ccbae8d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_e7b63fa5-be02-4a7c-b7f6-d9f3da57da72" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_b51dfc9a-5ef3-49a2-9f38-254861a88cfa" xlink:to="loc_us-gaap_CreditFacilityAxis_e7b63fa5-be02-4a7c-b7f6-d9f3da57da72" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_e7b63fa5-be02-4a7c-b7f6-d9f3da57da72_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_e7b63fa5-be02-4a7c-b7f6-d9f3da57da72" xlink:to="loc_us-gaap_CreditFacilityDomain_e7b63fa5-be02-4a7c-b7f6-d9f3da57da72_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_88f230ba-3433-4608-b4d2-a7c794877449" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_e7b63fa5-be02-4a7c-b7f6-d9f3da57da72" xlink:to="loc_us-gaap_CreditFacilityDomain_88f230ba-3433-4608-b4d2-a7c794877449" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_2ed25363-8c55-4563-9411-392e02413ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_88f230ba-3433-4608-b4d2-a7c794877449" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_2ed25363-8c55-4563-9411-392e02413ac6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_29e30cba-1827-4ccb-8325-99c580e2e21c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_b51dfc9a-5ef3-49a2-9f38-254861a88cfa" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_29e30cba-1827-4ccb-8325-99c580e2e21c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_29e30cba-1827-4ccb-8325-99c580e2e21c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_29e30cba-1827-4ccb-8325-99c580e2e21c" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_29e30cba-1827-4ccb-8325-99c580e2e21c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_03d659c7-fbc9-4616-9481-224df50b314e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_29e30cba-1827-4ccb-8325-99c580e2e21c" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_03d659c7-fbc9-4616-9481-224df50b314e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_InventoriesAndCurrentAssetsofDiscontinuedOperationsMember_e53291d5-d6a4-458e-812a-9d927faf0af3" xlink:href="unfi-20250802.xsd#unfi_InventoriesAndCurrentAssetsofDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_03d659c7-fbc9-4616-9481-224df50b314e" xlink:to="loc_unfi_InventoriesAndCurrentAssetsofDiscontinuedOperationsMember_e53291d5-d6a4-458e-812a-9d927faf0af3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ReceivablesandCurrentAssetsofDiscontinuedOperationsMember_d3477f4f-bfa8-4145-89f7-9401bbca5c75" xlink:href="unfi-20250802.xsd#unfi_ReceivablesandCurrentAssetsofDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_03d659c7-fbc9-4616-9481-224df50b314e" xlink:to="loc_unfi_ReceivablesandCurrentAssetsofDiscontinuedOperationsMember_d3477f4f-bfa8-4145-89f7-9401bbca5c75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_IntangibleAssetsNetMember_8600f711-036d-4888-8360-2a1e52236fa5" xlink:href="unfi-20250802.xsd#unfi_IntangibleAssetsNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_03d659c7-fbc9-4616-9481-224df50b314e" xlink:to="loc_unfi_IntangibleAssetsNetMember_8600f711-036d-4888-8360-2a1e52236fa5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCollateralAmount_2da5cc6c-c74e-421e-9275-9436765ffbc2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentCollateralAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_bc9da3c6-b807-4148-9a72-4e1b0cd06be9" xlink:to="loc_us-gaap_DebtInstrumentCollateralAmount_2da5cc6c-c74e-421e-9275-9436765ffbc2" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LONGTERMDEBTUnusedCreditundertheABLFacilitiesDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LONGTERMDEBTUnusedCreditundertheABLFacilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LONGTERMDEBTUnusedCreditundertheABLFacilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_6e5d514b-a07e-4c4d-8442-b3df236ed3ac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_4bb972ca-3faf-483b-83b8-7e55cdaed6fd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_6e5d514b-a07e-4c4d-8442-b3df236ed3ac" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_4bb972ca-3faf-483b-83b8-7e55cdaed6fd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_cd4e0a3f-6684-451b-94c0-3f193303d591" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_4bb972ca-3faf-483b-83b8-7e55cdaed6fd" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_cd4e0a3f-6684-451b-94c0-3f193303d591" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_cd4e0a3f-6684-451b-94c0-3f193303d591_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_cd4e0a3f-6684-451b-94c0-3f193303d591" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_cd4e0a3f-6684-451b-94c0-3f193303d591_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_2ca43046-278d-4569-8ed0-d20d2356648e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_cd4e0a3f-6684-451b-94c0-3f193303d591" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_2ca43046-278d-4569-8ed0-d20d2356648e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_351a6f52-7b3b-4fdd-a12e-656490294b09" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_2ca43046-278d-4569-8ed0-d20d2356648e" xlink:to="loc_us-gaap_LineOfCreditMember_351a6f52-7b3b-4fdd-a12e-656490294b09" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_0c276831-0b45-4168-9632-99d689b1edf7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_4bb972ca-3faf-483b-83b8-7e55cdaed6fd" xlink:to="loc_us-gaap_CreditFacilityAxis_0c276831-0b45-4168-9632-99d689b1edf7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_0c276831-0b45-4168-9632-99d689b1edf7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_0c276831-0b45-4168-9632-99d689b1edf7" xlink:to="loc_us-gaap_CreditFacilityDomain_0c276831-0b45-4168-9632-99d689b1edf7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_ca2240e0-da89-452d-a399-ed384e86c685" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_0c276831-0b45-4168-9632-99d689b1edf7" xlink:to="loc_us-gaap_CreditFacilityDomain_ca2240e0-da89-452d-a399-ed384e86c685" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_27ea2d28-cc84-4205-870d-04f3b0e616f4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_ca2240e0-da89-452d-a399-ed384e86c685" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_27ea2d28-cc84-4205-870d-04f3b0e616f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LetterOfCreditMember_1d9eeca0-2979-47b4-9fb2-7e5101d26a40" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LetterOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_ca2240e0-da89-452d-a399-ed384e86c685" xlink:to="loc_us-gaap_LetterOfCreditMember_1d9eeca0-2979-47b4-9fb2-7e5101d26a40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_0c6a23fd-2632-4286-aa40-d62914e95ed2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_4bb972ca-3faf-483b-83b8-7e55cdaed6fd" xlink:to="loc_us-gaap_DebtInstrumentAxis_0c6a23fd-2632-4286-aa40-d62914e95ed2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0c6a23fd-2632-4286-aa40-d62914e95ed2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_0c6a23fd-2632-4286-aa40-d62914e95ed2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0c6a23fd-2632-4286-aa40-d62914e95ed2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_26a37815-ad2e-446e-b0bc-2d9af2b7535f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_0c6a23fd-2632-4286-aa40-d62914e95ed2" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_26a37815-ad2e-446e-b0bc-2d9af2b7535f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ABLCreditFacilityMember_06ca4536-93e6-4e1f-bc00-822295195b22" xlink:href="unfi-20250802.xsd#unfi_ABLCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_26a37815-ad2e-446e-b0bc-2d9af2b7535f" xlink:to="loc_unfi_ABLCreditFacilityMember_06ca4536-93e6-4e1f-bc00-822295195b22" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ABLLoansMember_7b490a2a-7dfd-441c-b4a6-5866df6d9f5e" xlink:href="unfi-20250802.xsd#unfi_ABLLoansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_26a37815-ad2e-446e-b0bc-2d9af2b7535f" xlink:to="loc_unfi_ABLLoansMember_7b490a2a-7dfd-441c-b4a6-5866df6d9f5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_09c4a340-3bc8-49e9-b931-8f2f85ee404a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_6e5d514b-a07e-4c4d-8442-b3df236ed3ac" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_09c4a340-3bc8-49e9-b931-8f2f85ee404a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_958b7722-8cf7-4072-af65-7399e2cd5a73" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_6e5d514b-a07e-4c4d-8442-b3df236ed3ac" xlink:to="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_958b7722-8cf7-4072-af65-7399e2cd5a73" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LONGTERMDEBTSeniorNotesDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LONGTERMDEBTSeniorNotesDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LONGTERMDEBTSeniorNotesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_b326e809-7b36-4e4f-8b02-4debe2ef164d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_42775c47-04ed-42e2-ad50-1839e2aeb18f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b326e809-7b36-4e4f-8b02-4debe2ef164d" xlink:to="loc_us-gaap_DebtInstrumentTable_42775c47-04ed-42e2-ad50-1839e2aeb18f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_a9d2ec27-0608-4069-82f1-9c76e27b49e0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_42775c47-04ed-42e2-ad50-1839e2aeb18f" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_a9d2ec27-0608-4069-82f1-9c76e27b49e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_a9d2ec27-0608-4069-82f1-9c76e27b49e0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_a9d2ec27-0608-4069-82f1-9c76e27b49e0" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_a9d2ec27-0608-4069-82f1-9c76e27b49e0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_337f61db-f50f-4db4-9be9-798eb2574911" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_a9d2ec27-0608-4069-82f1-9c76e27b49e0" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_337f61db-f50f-4db4-9be9-798eb2574911" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_45a42c4e-474a-44e1-a35f-3e28d21f4ea2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_337f61db-f50f-4db4-9be9-798eb2574911" xlink:to="loc_us-gaap_SeniorNotesMember_45a42c4e-474a-44e1-a35f-3e28d21f4ea2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_d4721ba6-4fa4-47df-a4bf-0f6f7ea4310a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_42775c47-04ed-42e2-ad50-1839e2aeb18f" xlink:to="loc_us-gaap_DebtInstrumentAxis_d4721ba6-4fa4-47df-a4bf-0f6f7ea4310a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_d4721ba6-4fa4-47df-a4bf-0f6f7ea4310a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_d4721ba6-4fa4-47df-a4bf-0f6f7ea4310a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_d4721ba6-4fa4-47df-a4bf-0f6f7ea4310a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_0489bcdb-16ea-4f5a-9aa4-761e3668c2f4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_d4721ba6-4fa4-47df-a4bf-0f6f7ea4310a" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_0489bcdb-16ea-4f5a-9aa4-761e3668c2f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_SeniorNotesDueOctober20286750Member_c4dc7813-1974-4d91-b139-6e61127a482f" xlink:href="unfi-20250802.xsd#unfi_SeniorNotesDueOctober20286750Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_0489bcdb-16ea-4f5a-9aa4-761e3668c2f4" xlink:to="loc_unfi_SeniorNotesDueOctober20286750Member_c4dc7813-1974-4d91-b139-6e61127a482f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_1628e066-6b65-4f62-b6fe-8fe285641ec0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b326e809-7b36-4e4f-8b02-4debe2ef164d" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_1628e066-6b65-4f62-b6fe-8fe285641ec0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_9847fbf5-3723-40e5-94d5-617f76d57ce0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b326e809-7b36-4e4f-8b02-4debe2ef164d" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_9847fbf5-3723-40e5-94d5-617f76d57ce0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LONGTERMDEBTDebtCovenantsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LONGTERMDEBTDebtCovenantsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LONGTERMDEBTDebtCovenantsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityLineItems_9e47bb9a-2dc8-4bc4-844d-8c79c9d9eb81" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_6c5856c7-f896-45d2-a0a0-9a825e294245" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditFacilityTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_9e47bb9a-2dc8-4bc4-844d-8c79c9d9eb81" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_6c5856c7-f896-45d2-a0a0-9a825e294245" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_60d47fe3-678f-4a58-976a-9e76f00874a4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_6c5856c7-f896-45d2-a0a0-9a825e294245" xlink:to="loc_us-gaap_CreditFacilityAxis_60d47fe3-678f-4a58-976a-9e76f00874a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_60d47fe3-678f-4a58-976a-9e76f00874a4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_60d47fe3-678f-4a58-976a-9e76f00874a4" xlink:to="loc_us-gaap_CreditFacilityDomain_60d47fe3-678f-4a58-976a-9e76f00874a4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_059410b1-a0cd-4bfa-b3e4-e23d5ecc0915" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_60d47fe3-678f-4a58-976a-9e76f00874a4" xlink:to="loc_us-gaap_CreditFacilityDomain_059410b1-a0cd-4bfa-b3e4-e23d5ecc0915" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_e72b6309-3298-4aab-9bd9-c310c1b384cf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_059410b1-a0cd-4bfa-b3e4-e23d5ecc0915" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_e72b6309-3298-4aab-9bd9-c310c1b384cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_7246431c-ea0b-403f-900a-2a89645e60be" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_6c5856c7-f896-45d2-a0a0-9a825e294245" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_7246431c-ea0b-403f-900a-2a89645e60be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_7246431c-ea0b-403f-900a-2a89645e60be_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_7246431c-ea0b-403f-900a-2a89645e60be" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_7246431c-ea0b-403f-900a-2a89645e60be_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_abd5f022-aa06-4b0c-9e24-1b1ad8763132" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_7246431c-ea0b-403f-900a-2a89645e60be" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_abd5f022-aa06-4b0c-9e24-1b1ad8763132" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_a97eb296-87cb-466b-8dfe-d4fc83b14143" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_abd5f022-aa06-4b0c-9e24-1b1ad8763132" xlink:to="loc_us-gaap_LineOfCreditMember_a97eb296-87cb-466b-8dfe-d4fc83b14143" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_de57b4df-421d-4427-9fb9-78184b8a1f86" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_6c5856c7-f896-45d2-a0a0-9a825e294245" xlink:to="loc_us-gaap_DebtInstrumentAxis_de57b4df-421d-4427-9fb9-78184b8a1f86" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_de57b4df-421d-4427-9fb9-78184b8a1f86_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_de57b4df-421d-4427-9fb9-78184b8a1f86" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_de57b4df-421d-4427-9fb9-78184b8a1f86_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_1ebb3990-ca75-4ac1-b68b-fdfb85916d49" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_de57b4df-421d-4427-9fb9-78184b8a1f86" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_1ebb3990-ca75-4ac1-b68b-fdfb85916d49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ABLCreditFacilityMember_80eb4def-bed9-484a-878a-53a4f80a93cd" xlink:href="unfi-20250802.xsd#unfi_ABLCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_1ebb3990-ca75-4ac1-b68b-fdfb85916d49" xlink:to="loc_unfi_ABLCreditFacilityMember_80eb4def-bed9-484a-878a-53a4f80a93cd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DebtInstrumentCovenantTermsFixedChargeCoverageRatioMinimum_5442fd0d-cd5e-4adc-9f9f-db7a3b9aba3b" xlink:href="unfi-20250802.xsd#unfi_DebtInstrumentCovenantTermsFixedChargeCoverageRatioMinimum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_9e47bb9a-2dc8-4bc4-844d-8c79c9d9eb81" xlink:to="loc_unfi_DebtInstrumentCovenantTermsFixedChargeCoverageRatioMinimum_5442fd0d-cd5e-4adc-9f9f-db7a3b9aba3b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_2e3e5e03-c783-4002-833e-c13c94299755" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_9e47bb9a-2dc8-4bc4-844d-8c79c9d9eb81" xlink:to="loc_us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_2e3e5e03-c783-4002-833e-c13c94299755" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DebtInstrumentUnusedBorrowingCapacityNoFILOLoansOutstandingAmount_3e0e2e34-481b-417c-af8a-d504d37d310e" xlink:href="unfi-20250802.xsd#unfi_DebtInstrumentUnusedBorrowingCapacityNoFILOLoansOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_9e47bb9a-2dc8-4bc4-844d-8c79c9d9eb81" xlink:to="loc_unfi_DebtInstrumentUnusedBorrowingCapacityNoFILOLoansOutstandingAmount_3e0e2e34-481b-417c-af8a-d504d37d310e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DebtInstrumentUnusedBorrowingCapacityPercentageOfBorrowingBase_04c081c1-d545-430b-94dc-583cf9f0c43c" xlink:href="unfi-20250802.xsd#unfi_DebtInstrumentUnusedBorrowingCapacityPercentageOfBorrowingBase"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityLineItems_9e47bb9a-2dc8-4bc4-844d-8c79c9d9eb81" xlink:to="loc_unfi_DebtInstrumentUnusedBorrowingCapacityPercentageOfBorrowingBase_04c081c1-d545-430b-94dc-583cf9f0c43c" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/COMPREHENSIVELOSSINCOMEANDACCUMULATEDOTHERCOMPREHENSIVELOSSChangesbyComponentDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#COMPREHENSIVELOSSINCOMEANDACCUMULATEDOTHERCOMPREHENSIVELOSSChangesbyComponentDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/COMPREHENSIVELOSSINCOMEANDACCUMULATEDOTHERCOMPREHENSIVELOSSChangesbyComponentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_62e61907-8bbc-41ac-94c9-1b57d8dcf1a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_3f44f9ca-3526-43ae-bef0-e82eea489580" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_62e61907-8bbc-41ac-94c9-1b57d8dcf1a9" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_3f44f9ca-3526-43ae-bef0-e82eea489580" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_00aefe8d-7b73-4613-a98a-bbf675f50c67" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_3f44f9ca-3526-43ae-bef0-e82eea489580" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_00aefe8d-7b73-4613-a98a-bbf675f50c67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_00aefe8d-7b73-4613-a98a-bbf675f50c67_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_00aefe8d-7b73-4613-a98a-bbf675f50c67" xlink:to="loc_us-gaap_EquityComponentDomain_00aefe8d-7b73-4613-a98a-bbf675f50c67_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_ad5f6b96-8efb-42ef-b773-13b77207e75c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_00aefe8d-7b73-4613-a98a-bbf675f50c67" xlink:to="loc_us-gaap_EquityComponentDomain_ad5f6b96-8efb-42ef-b773-13b77207e75c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_617dee10-1fd0-4e67-bd5a-aa0a9a6c00d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ad5f6b96-8efb-42ef-b773-13b77207e75c" xlink:to="loc_us-gaap_AccumulatedGainLossCashFlowHedgeIncludingNoncontrollingInterestMember_617dee10-1fd0-4e67-bd5a-aa0a9a6c00d9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember_fbd21ae0-b04e-4753-a22f-f762e159baac" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ad5f6b96-8efb-42ef-b773-13b77207e75c" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember_fbd21ae0-b04e-4753-a22f-f762e159baac" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember_3fa5cb67-7c88-49e7-a73b-682c1951fa22" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ad5f6b96-8efb-42ef-b773-13b77207e75c" xlink:to="loc_us-gaap_AccumulatedForeignCurrencyAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember_3fa5cb67-7c88-49e7-a73b-682c1951fa22" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_fd4f2bb2-0ca8-4474-918e-3fcd8c9f44c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_ad5f6b96-8efb-42ef-b773-13b77207e75c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_fd4f2bb2-0ca8-4474-918e-3fcd8c9f44c7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_4f641361-3d2a-40dc-b864-a834bf773257" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_3f44f9ca-3526-43ae-bef0-e82eea489580" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_4f641361-3d2a-40dc-b864-a834bf773257" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_4f641361-3d2a-40dc-b864-a834bf773257_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4f641361-3d2a-40dc-b864-a834bf773257" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_4f641361-3d2a-40dc-b864-a834bf773257_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_f14a0de2-3175-4f32-b130-0e0518beecbe" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_4f641361-3d2a-40dc-b864-a834bf773257" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_f14a0de2-3175-4f32-b130-0e0518beecbe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherContractMember_e56db48b-42f6-4d1b-b785-fe4a897b9e36" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherContractMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_f14a0de2-3175-4f32-b130-0e0518beecbe" xlink:to="loc_us-gaap_OtherContractMember_e56db48b-42f6-4d1b-b785-fe4a897b9e36" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_SwapAgreementsMember_1a825a11-3a5a-49f7-945a-ed2b836ae27d" xlink:href="unfi-20250802.xsd#unfi_SwapAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_f14a0de2-3175-4f32-b130-0e0518beecbe" xlink:to="loc_unfi_SwapAgreementsMember_1a825a11-3a5a-49f7-945a-ed2b836ae27d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_136a63e4-eef8-43e1-9c7e-210424ae369f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_62e61907-8bbc-41ac-94c9-1b57d8dcf1a9" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_136a63e4-eef8-43e1-9c7e-210424ae369f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_c48455b8-cd8d-495f-8d9a-62e9b50bb68f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_136a63e4-eef8-43e1-9c7e-210424ae369f" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_c48455b8-cd8d-495f-8d9a-62e9b50bb68f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_11f7b1fa-4b99-43c6-9117-af68e1aea79b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_136a63e4-eef8-43e1-9c7e-210424ae369f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax_11f7b1fa-4b99-43c6-9117-af68e1aea79b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_9fe78d74-34a6-482c-b6dc-23991d6926e6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_136a63e4-eef8-43e1-9c7e-210424ae369f" xlink:to="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax_9fe78d74-34a6-482c-b6dc-23991d6926e6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_a8f83d00-c369-41ed-8760-162e53750337" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTaxAbstract_136a63e4-eef8-43e1-9c7e-210424ae369f" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_a8f83d00-c369-41ed-8760-162e53750337" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_b2a9b7e6-2f24-44b2-8f99-84b93ac6340a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/COMPREHENSIVELOSSINCOMEANDACCUMULATEDOTHERCOMPREHENSIVELOSSReclassificationoutofOtherComprehensiveLossDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#COMPREHENSIVELOSSINCOMEANDACCUMULATEDOTHERCOMPREHENSIVELOSSReclassificationoutofOtherComprehensiveLossDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/COMPREHENSIVELOSSINCOMEANDACCUMULATEDOTHERCOMPREHENSIVELOSSReclassificationoutofOtherComprehensiveLossDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_86a0259e-a40c-45b2-9b44-8fe831da7647" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_548af10d-2fb3-42bb-bb95-206c482d2c1f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_86a0259e-a40c-45b2-9b44-8fe831da7647" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_548af10d-2fb3-42bb-bb95-206c482d2c1f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_5ef46105-d33f-4344-8540-2fd8a58c5b92" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_548af10d-2fb3-42bb-bb95-206c482d2c1f" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_5ef46105-d33f-4344-8540-2fd8a58c5b92" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_5ef46105-d33f-4344-8540-2fd8a58c5b92_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_5ef46105-d33f-4344-8540-2fd8a58c5b92" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_5ef46105-d33f-4344-8540-2fd8a58c5b92_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_7dc3d481-d5d4-4640-89f8-cf80e9663e17" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeAxis_5ef46105-d33f-4344-8540-2fd8a58c5b92" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_7dc3d481-d5d4-4640-89f8-cf80e9663e17" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_9124ffbd-689f-41dc-938c-0582584b1aab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeDomain_7dc3d481-d5d4-4640-89f8-cf80e9663e17" xlink:to="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeMember_9124ffbd-689f-41dc-938c-0582584b1aab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_c8b02cb0-75bc-4eaf-91bd-be0a87cad919" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_548af10d-2fb3-42bb-bb95-206c482d2c1f" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_c8b02cb0-75bc-4eaf-91bd-be0a87cad919" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c8b02cb0-75bc-4eaf-91bd-be0a87cad919_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c8b02cb0-75bc-4eaf-91bd-be0a87cad919" xlink:to="loc_us-gaap_EquityComponentDomain_c8b02cb0-75bc-4eaf-91bd-be0a87cad919_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f20f3910-3855-4e1e-8536-67cde5859e63" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c8b02cb0-75bc-4eaf-91bd-be0a87cad919" xlink:to="loc_us-gaap_EquityComponentDomain_f20f3910-3855-4e1e-8536-67cde5859e63" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_f39feca7-b562-49f7-9fac-b70c9e4ddf4b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f20f3910-3855-4e1e-8536-67cde5859e63" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentNetPriorServiceCostCreditMember_f39feca7-b562-49f7-9fac-b70c9e4ddf4b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember_350cbf56-25aa-4d17-9684-bdda4a29b4c9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f20f3910-3855-4e1e-8536-67cde5859e63" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentIncludingPortionAttributableToNoncontrollingInterestMember_350cbf56-25aa-4d17-9684-bdda4a29b4c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_5f84faa9-929d-42df-92b9-0e9db37d3c44" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f20f3910-3855-4e1e-8536-67cde5859e63" xlink:to="loc_us-gaap_AccumulatedGainLossNetCashFlowHedgeParentMember_5f84faa9-929d-42df-92b9-0e9db37d3c44" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_8b5274f2-140e-40ef-9b51-2ac24f628464" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReclassificationOutOfAccumulatedOtherComprehensiveIncomeTable_548af10d-2fb3-42bb-bb95-206c482d2c1f" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_8b5274f2-140e-40ef-9b51-2ac24f628464" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_8b5274f2-140e-40ef-9b51-2ac24f628464_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_8b5274f2-140e-40ef-9b51-2ac24f628464" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_8b5274f2-140e-40ef-9b51-2ac24f628464_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_ab8b0818-1e95-42ae-9455-6b2a258b4217" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_8b5274f2-140e-40ef-9b51-2ac24f628464" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_ab8b0818-1e95-42ae-9455-6b2a258b4217" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_SwapAgreementsMember_91c706be-2c24-4ef0-9214-f2ddfeadf17c" xlink:href="unfi-20250802.xsd#unfi_SwapAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ab8b0818-1e95-42ae-9455-6b2a258b4217" xlink:to="loc_unfi_SwapAgreementsMember_91c706be-2c24-4ef0-9214-f2ddfeadf17c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_OtherCashFlowHedgesMember_77f48f95-3521-40fe-baeb-505b8f5a22a6" xlink:href="unfi-20250802.xsd#unfi_OtherCashFlowHedgesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_ab8b0818-1e95-42ae-9455-6b2a258b4217" xlink:to="loc_unfi_OtherCashFlowHedgesMember_77f48f95-3521-40fe-baeb-505b8f5a22a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent_b0befbec-701f-4f34-b1cf-eb8cfa53d65f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_86a0259e-a40c-45b2-9b44-8fe831da7647" xlink:to="loc_us-gaap_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent_b0befbec-701f-4f34-b1cf-eb8cfa53d65f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_67691c90-3ed7-4d66-8ea3-6fabeb80f5b1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_86a0259e-a40c-45b2-9b44-8fe831da7647" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_67691c90-3ed7-4d66-8ea3-6fabeb80f5b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_b9cc58e0-d1fb-43f9-91d2-2bc76dcd097f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestIncomeExpenseNonoperatingNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_86a0259e-a40c-45b2-9b44-8fe831da7647" xlink:to="loc_us-gaap_InterestIncomeExpenseNonoperatingNet_b9cc58e0-d1fb-43f9-91d2-2bc76dcd097f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_0981efdc-5750-4ee9-b235-7234b167c5fd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_86a0259e-a40c-45b2-9b44-8fe831da7647" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_0981efdc-5750-4ee9-b235-7234b167c5fd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_a2da35ed-ae93-4978-9dd2-f31352e946b4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReclassificationAdjustmentOutOfAccumulatedOtherComprehensiveIncomeLineItems_86a0259e-a40c-45b2-9b44-8fe831da7647" xlink:to="loc_us-gaap_ProfitLoss_a2da35ed-ae93-4978-9dd2-f31352e946b4" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LEASESLeaseCostDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LEASESLeaseCostDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LEASESLeaseCostDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_29f2abf8-4cf2-4bfb-abe0-4cf4e63434dd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_29f2abf8-4cf2-4bfb-abe0-4cf4e63434dd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_7687c9b9-6f6f-4a5c-9712-1d29f73fdc3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_29f2abf8-4cf2-4bfb-abe0-4cf4e63434dd" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_7687c9b9-6f6f-4a5c-9712-1d29f73fdc3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_7687c9b9-6f6f-4a5c-9712-1d29f73fdc3a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_7687c9b9-6f6f-4a5c-9712-1d29f73fdc3a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_7687c9b9-6f6f-4a5c-9712-1d29f73fdc3a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_aec18424-1198-4817-a210-f0e0660f5d3c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_7687c9b9-6f6f-4a5c-9712-1d29f73fdc3a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_aec18424-1198-4817-a210-f0e0660f5d3c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenseMember_20178cea-5fb7-4870-9043-721d4b430d1a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_aec18424-1198-4817-a210-f0e0660f5d3c" xlink:to="loc_us-gaap_OperatingExpenseMember_20178cea-5fb7-4870-9043-721d4b430d1a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesMember_80a607bd-1739-41f9-b818-1c33bfd91034" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_aec18424-1198-4817-a210-f0e0660f5d3c" xlink:to="loc_us-gaap_SalesMember_80a607bd-1739-41f9-b818-1c33bfd91034" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringChargesMember_db7e817c-1d20-4dc9-9dcc-cd5f88172bd6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringChargesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_aec18424-1198-4817-a210-f0e0660f5d3c" xlink:to="loc_us-gaap_RestructuringChargesMember_db7e817c-1d20-4dc9-9dcc-cd5f88172bd6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseMember_addf77c8-659c-4610-bc91-5486f1e58c6c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_aec18424-1198-4817-a210-f0e0660f5d3c" xlink:to="loc_us-gaap_InterestExpenseMember_addf77c8-659c-4610-bc91-5486f1e58c6c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost_b7787332-f51d-403e-a99b-ff0606d19bab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_us-gaap_OperatingLeaseCost_b7787332-f51d-403e-a99b-ff0606d19bab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermLeaseCost_38629db7-e5c8-47f7-b43c-78135414b727" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShortTermLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_us-gaap_ShortTermLeaseCost_38629db7-e5c8-47f7-b43c-78135414b727" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableLeaseCost_668f0901-559c-4dd5-bb36-75080e4bdd2c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_VariableLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_us-gaap_VariableLeaseCost_668f0901-559c-4dd5-bb36-75080e4bdd2c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubleaseIncome_8a236c9a-1619-42a8-9993-53c001f6d022" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SubleaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_us-gaap_SubleaseIncome_8a236c9a-1619-42a8-9993-53c001f6d022" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_Othersubleaseincomenet_fc858347-f9fa-4674-af5b-d59b828462f4" xlink:href="unfi-20250802.xsd#unfi_Othersubleaseincomenet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_unfi_Othersubleaseincomenet_fc858347-f9fa-4674-af5b-d59b828462f4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost_dbb62852-f62a-4c50-8696-5954e455fb82" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseCost"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization_a27f22fb-c047-4fb4-a166-b900f9804320" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseRightOfUseAssetAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_us-gaap_FinanceLeaseRightOfUseAssetAmortization_a27f22fb-c047-4fb4-a166-b900f9804320" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseInterestExpense_af52dcd0-199f-4893-a945-ec39c8d33457" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FinanceLeaseInterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_us-gaap_FinanceLeaseInterestExpense_af52dcd0-199f-4893-a945-ec39c8d33457" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_Financeleasecost_fd87980d-5611-448c-930c-d4d21fa0bec3" xlink:href="unfi-20250802.xsd#unfi_Financeleasecost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_unfi_Financeleasecost_fd87980d-5611-448c-930c-d4d21fa0bec3" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCost_34a5e277-e70c-4d99-b151-d0de3d2bbf74" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_us-gaap_LeaseCost_34a5e277-e70c-4d99-b151-d0de3d2bbf74" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseExpense_afc808d1-36d1-46f7-a8a1-ea6bdb71f244" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_c0ed34f1-aaf6-41b9-a1d8-58f7351d7768" xlink:to="loc_us-gaap_OperatingLeaseExpense_afc808d1-36d1-46f7-a8a1-ea6bdb71f244" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/LEASESNarrativeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#LEASESNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/LEASESNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionLineItems_51188575-0a89-47fa-a8d2-417c31b40634" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleLeasebackTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionTable_fe7d193f-aa67-4a65-a66e-709eebe9faeb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SaleLeasebackTransactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems_51188575-0a89-47fa-a8d2-417c31b40634" xlink:to="loc_us-gaap_SaleLeasebackTransactionTable_fe7d193f-aa67-4a65-a66e-709eebe9faeb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_89c1f9a0-b28e-45b3-9226-4d218133787b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable_fe7d193f-aa67-4a65-a66e-709eebe9faeb" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_89c1f9a0-b28e-45b3-9226-4d218133787b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_89c1f9a0-b28e-45b3-9226-4d218133787b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_89c1f9a0-b28e-45b3-9226-4d218133787b" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_89c1f9a0-b28e-45b3-9226-4d218133787b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_06aac807-b976-4b2a-9f5c-cda868ff999e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_89c1f9a0-b28e-45b3-9226-4d218133787b" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_06aac807-b976-4b2a-9f5c-cda868ff999e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_f204b55e-95f5-42c6-ae08-075a1e6537c1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_06aac807-b976-4b2a-9f5c-cda868ff999e" xlink:to="loc_us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember_f204b55e-95f5-42c6-ae08-075a1e6537c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_753c1e97-f705-4ac5-9b18-468276b43561" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable_fe7d193f-aa67-4a65-a66e-709eebe9faeb" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_753c1e97-f705-4ac5-9b18-468276b43561" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_753c1e97-f705-4ac5-9b18-468276b43561_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_753c1e97-f705-4ac5-9b18-468276b43561" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_753c1e97-f705-4ac5-9b18-468276b43561_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_92853527-b734-426e-b08d-277c3638a6a3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_753c1e97-f705-4ac5-9b18-468276b43561" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_92853527-b734-426e-b08d-277c3638a6a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_PennsylvaniaDistributionCenterMember_133c91f9-9d9c-43d2-a7dc-7d7b90f48476" xlink:href="unfi-20250802.xsd#unfi_PennsylvaniaDistributionCenterMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_92853527-b734-426e-b08d-277c3638a6a3" xlink:to="loc_unfi_PennsylvaniaDistributionCenterMember_133c91f9-9d9c-43d2-a7dc-7d7b90f48476" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_0b271444-decc-462a-a8e1-856540cdd4c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems_51188575-0a89-47fa-a8d2-417c31b40634" xlink:to="loc_us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf_0b271444-decc-462a-a8e1-856540cdd4c7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseImpairmentLoss_b6a2a405-64c7-4759-8f59-2c3584422d2f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLeaseImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems_51188575-0a89-47fa-a8d2-417c31b40634" xlink:to="loc_us-gaap_OperatingLeaseImpairmentLoss_b6a2a405-64c7-4759-8f59-2c3584422d2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_3ea5a9a1-8a44-451e-a9e0-9c0fc6604fcd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems_51188575-0a89-47fa-a8d2-417c31b40634" xlink:to="loc_us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability_3ea5a9a1-8a44-451e-a9e0-9c0fc6604fcd" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/SHAREBASEDAWARDSNarrativeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#SHAREBASEDAWARDSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/SHAREBASEDAWARDSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0c20aeb6-be26-4584-bf6a-8951f8a25a3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4602e10b-f876-4788-9df5-b8b422f588ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0c20aeb6-be26-4584-bf6a-8951f8a25a3a" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4602e10b-f876-4788-9df5-b8b422f588ab" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_b4307886-cfaf-481d-a84c-09aa00a6a0d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4602e10b-f876-4788-9df5-b8b422f588ab" xlink:to="loc_us-gaap_PlanNameAxis_b4307886-cfaf-481d-a84c-09aa00a6a0d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_b4307886-cfaf-481d-a84c-09aa00a6a0d9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_b4307886-cfaf-481d-a84c-09aa00a6a0d9" xlink:to="loc_us-gaap_PlanNameDomain_b4307886-cfaf-481d-a84c-09aa00a6a0d9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_9678e000-58b4-44f7-9b1d-e26664e8ea9b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_b4307886-cfaf-481d-a84c-09aa00a6a0d9" xlink:to="loc_us-gaap_PlanNameDomain_9678e000-58b4-44f7-9b1d-e26664e8ea9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_A2020EquityIncentivePlanMember_fe4fc403-6010-41f8-b839-3cc1424fdd4e" xlink:href="unfi-20250802.xsd#unfi_A2020EquityIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_9678e000-58b4-44f7-9b1d-e26664e8ea9b" xlink:to="loc_unfi_A2020EquityIncentivePlanMember_fe4fc403-6010-41f8-b839-3cc1424fdd4e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GranteeStatusAxis_d20a4f7c-e03b-4bda-856f-f93a2e25c0b1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GranteeStatusAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4602e10b-f876-4788-9df5-b8b422f588ab" xlink:to="loc_us-gaap_GranteeStatusAxis_d20a4f7c-e03b-4bda-856f-f93a2e25c0b1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GranteeStatusDomain_d20a4f7c-e03b-4bda-856f-f93a2e25c0b1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GranteeStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GranteeStatusAxis_d20a4f7c-e03b-4bda-856f-f93a2e25c0b1" xlink:to="loc_us-gaap_GranteeStatusDomain_d20a4f7c-e03b-4bda-856f-f93a2e25c0b1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GranteeStatusDomain_74272a07-bb36-4405-85f4-560462aba460" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GranteeStatusDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GranteeStatusAxis_d20a4f7c-e03b-4bda-856f-f93a2e25c0b1" xlink:to="loc_us-gaap_GranteeStatusDomain_74272a07-bb36-4405-85f4-560462aba460" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedPaymentArrangementNonemployeeMember_0fe07ccd-b4c0-4713-9658-03abd6432557" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedPaymentArrangementNonemployeeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GranteeStatusDomain_74272a07-bb36-4405-85f4-560462aba460" xlink:to="loc_us-gaap_ShareBasedPaymentArrangementNonemployeeMember_0fe07ccd-b4c0-4713-9658-03abd6432557" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedPaymentArrangementEmployeeMember_cb38a5c0-3d66-4a52-a659-5327d89d52c2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedPaymentArrangementEmployeeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GranteeStatusDomain_74272a07-bb36-4405-85f4-560462aba460" xlink:to="loc_us-gaap_ShareBasedPaymentArrangementEmployeeMember_cb38a5c0-3d66-4a52-a659-5327d89d52c2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_6def0cb1-32ff-4e2b-8c21-16f71e686ebf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4602e10b-f876-4788-9df5-b8b422f588ab" xlink:to="loc_us-gaap_AwardTypeAxis_6def0cb1-32ff-4e2b-8c21-16f71e686ebf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6def0cb1-32ff-4e2b-8c21-16f71e686ebf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_6def0cb1-32ff-4e2b-8c21-16f71e686ebf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6def0cb1-32ff-4e2b-8c21-16f71e686ebf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f5256af7-dd56-4795-a14e-e99ad6c3b264" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_6def0cb1-32ff-4e2b-8c21-16f71e686ebf" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f5256af7-dd56-4795-a14e-e99ad6c3b264" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_a4e86e0a-0c9a-474d-94fe-79031ac0f1fa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f5256af7-dd56-4795-a14e-e99ad6c3b264" xlink:to="loc_us-gaap_RestrictedStockMember_a4e86e0a-0c9a-474d-94fe-79031ac0f1fa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_6fa38859-464d-474a-8b26-3a965ab099b2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f5256af7-dd56-4795-a14e-e99ad6c3b264" xlink:to="loc_us-gaap_PerformanceSharesMember_6fa38859-464d-474a-8b26-3a965ab099b2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_e1f31a33-2097-412a-a6f8-5f650f87552f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0c20aeb6-be26-4584-bf6a-8951f8a25a3a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_e1f31a33-2097-412a-a6f8-5f650f87552f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_3c472fc9-1eac-48d4-8b96-bbc92cb0419c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0c20aeb6-be26-4584-bf6a-8951f8a25a3a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_3c472fc9-1eac-48d4-8b96-bbc92cb0419c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfInstallments_b8c3ce7f-d85f-43e2-8b6c-3c802b04d1e2" xlink:href="unfi-20250802.xsd#unfi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfInstallments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0c20aeb6-be26-4584-bf6a-8951f8a25a3a" xlink:to="loc_unfi_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfInstallments_b8c3ce7f-d85f-43e2-8b6c-3c802b04d1e2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_b30fad49-d425-4813-b09f-a83786f72a4d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0c20aeb6-be26-4584-bf6a-8951f8a25a3a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_b30fad49-d425-4813-b09f-a83786f72a4d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_05394f4f-9a9d-4e8c-b056-2936be23fb12" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0c20aeb6-be26-4584-bf6a-8951f8a25a3a" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_05394f4f-9a9d-4e8c-b056-2936be23fb12" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_f330f3b3-818a-49d6-bd7f-2a722cd0f65d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0c20aeb6-be26-4584-bf6a-8951f8a25a3a" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_f330f3b3-818a-49d6-bd7f-2a722cd0f65d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationCashBasedArrangementsLiabilityCurrent_ffc142f9-a5fd-49a3-ab59-93a642cbbe49" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredCompensationCashBasedArrangementsLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0c20aeb6-be26-4584-bf6a-8951f8a25a3a" xlink:to="loc_us-gaap_DeferredCompensationCashBasedArrangementsLiabilityCurrent_ffc142f9-a5fd-49a3-ab59-93a642cbbe49" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/SHAREBASEDAWARDSShareBasedCompensationExpenseDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#SHAREBASEDAWARDSShareBasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/SHAREBASEDAWARDSShareBasedCompensationExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a4a2dc2c-8a99-4dd3-b8c8-2e688018111e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61313431-30bc-408f-8ff9-462170ece27b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a4a2dc2c-8a99-4dd3-b8c8-2e688018111e" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61313431-30bc-408f-8ff9-462170ece27b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_55be70b1-871b-40f6-9605-34a0910c9d15" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61313431-30bc-408f-8ff9-462170ece27b" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_55be70b1-871b-40f6-9605-34a0910c9d15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_55be70b1-871b-40f6-9605-34a0910c9d15_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_55be70b1-871b-40f6-9605-34a0910c9d15" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_55be70b1-871b-40f6-9605-34a0910c9d15_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_dbc46f3e-5bad-421b-ae2e-4b0ca476e080" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_55be70b1-871b-40f6-9605-34a0910c9d15" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_dbc46f3e-5bad-421b-ae2e-4b0ca476e080" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenseMember_2c026d1a-1b39-4358-82bd-245ed2df99de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_dbc46f3e-5bad-421b-ae2e-4b0ca476e080" xlink:to="loc_us-gaap_OperatingExpenseMember_2c026d1a-1b39-4358-82bd-245ed2df99de" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RestructuringAcquisitionandIntegrationRelatedExpensesMember_dd06c707-c124-4750-9eb0-18e13d8f95d9" xlink:href="unfi-20250802.xsd#unfi_RestructuringAcquisitionandIntegrationRelatedExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_dbc46f3e-5bad-421b-ae2e-4b0ca476e080" xlink:to="loc_unfi_RestructuringAcquisitionandIntegrationRelatedExpensesMember_dd06c707-c124-4750-9eb0-18e13d8f95d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_f1b7591d-7598-4dac-afe0-797a48b68d14" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61313431-30bc-408f-8ff9-462170ece27b" xlink:to="loc_us-gaap_AwardTypeAxis_f1b7591d-7598-4dac-afe0-797a48b68d14" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f1b7591d-7598-4dac-afe0-797a48b68d14_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_f1b7591d-7598-4dac-afe0-797a48b68d14" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f1b7591d-7598-4dac-afe0-797a48b68d14_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_95eb1118-1394-4081-ba0e-a6786fbe4fcd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_f1b7591d-7598-4dac-afe0-797a48b68d14" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_95eb1118-1394-4081-ba0e-a6786fbe4fcd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_7d0b3e7d-b6b7-4f7e-af75-8ea609dfea00" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_95eb1118-1394-4081-ba0e-a6786fbe4fcd" xlink:to="loc_us-gaap_RestrictedStockMember_7d0b3e7d-b6b7-4f7e-af75-8ea609dfea00" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_PerformanceAwardMember_21f4fc90-a34f-4c2b-b285-5de5fc1672d9" xlink:href="unfi-20250802.xsd#unfi_PerformanceAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_95eb1118-1394-4081-ba0e-a6786fbe4fcd" xlink:to="loc_unfi_PerformanceAwardMember_21f4fc90-a34f-4c2b-b285-5de5fc1672d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_a3a586f8-4a74-4030-a78d-6bcc99286a89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a4a2dc2c-8a99-4dd3-b8c8-2e688018111e" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_a3a586f8-4a74-4030-a78d-6bcc99286a89" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_0206bb26-f7be-4900-83aa-10765b43dcea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a4a2dc2c-8a99-4dd3-b8c8-2e688018111e" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_0206bb26-f7be-4900-83aa-10765b43dcea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_6e500de1-4458-4ab3-ad8c-09b6c2646006" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a4a2dc2c-8a99-4dd3-b8c8-2e688018111e" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax_6e500de1-4458-4ab3-ad8c-09b6c2646006" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/SHAREBASEDAWARDSRestrictedStockAwardsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#SHAREBASEDAWARDSRestrictedStockAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/SHAREBASEDAWARDSRestrictedStockAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_24ca9fa8-f6e4-46db-b5de-16e31f3a1820" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7736812c-d671-46c5-87a7-da8497b208ce" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_24ca9fa8-f6e4-46db-b5de-16e31f3a1820" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7736812c-d671-46c5-87a7-da8497b208ce" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_ca72a659-44ee-4823-a094-56c50aecffbb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7736812c-d671-46c5-87a7-da8497b208ce" xlink:to="loc_us-gaap_AwardTypeAxis_ca72a659-44ee-4823-a094-56c50aecffbb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ca72a659-44ee-4823-a094-56c50aecffbb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_ca72a659-44ee-4823-a094-56c50aecffbb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ca72a659-44ee-4823-a094-56c50aecffbb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_79037cab-a7a5-4a64-a6cb-4bc295d2a20e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_ca72a659-44ee-4823-a094-56c50aecffbb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_79037cab-a7a5-4a64-a6cb-4bc295d2a20e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RestrictedStockUnitsAndPerformanceStockUnitsMember_eab17cff-4f5f-472a-ae89-9f3d35efaadc" xlink:href="unfi-20250802.xsd#unfi_RestrictedStockUnitsAndPerformanceStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_79037cab-a7a5-4a64-a6cb-4bc295d2a20e" xlink:to="loc_unfi_RestrictedStockUnitsAndPerformanceStockUnitsMember_eab17cff-4f5f-472a-ae89-9f3d35efaadc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RestrictedStockUnitsAndPerformanceStockUnitsEquityClassifiedMember_cd169421-f1aa-4d95-b572-2d7d72329081" xlink:href="unfi-20250802.xsd#unfi_RestrictedStockUnitsAndPerformanceStockUnitsEquityClassifiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_RestrictedStockUnitsAndPerformanceStockUnitsMember_eab17cff-4f5f-472a-ae89-9f3d35efaadc" xlink:to="loc_unfi_RestrictedStockUnitsAndPerformanceStockUnitsEquityClassifiedMember_cd169421-f1aa-4d95-b572-2d7d72329081" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RestrictedStockUnitsAndPerformanceStockUnitsLiabilityClassifiedMember_af4fa3b3-ccb3-46b4-b5b6-1a8fe38ac218" xlink:href="unfi-20250802.xsd#unfi_RestrictedStockUnitsAndPerformanceStockUnitsLiabilityClassifiedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_RestrictedStockUnitsAndPerformanceStockUnitsMember_eab17cff-4f5f-472a-ae89-9f3d35efaadc" xlink:to="loc_unfi_RestrictedStockUnitsAndPerformanceStockUnitsLiabilityClassifiedMember_af4fa3b3-ccb3-46b4-b5b6-1a8fe38ac218" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_893a2f38-ac0d-4f9d-a1b1-017082f8c831" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_24ca9fa8-f6e4-46db-b5de-16e31f3a1820" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_893a2f38-ac0d-4f9d-a1b1-017082f8c831" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_27c7530d-4d97-4eb5-8965-2b76e3b33520" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_893a2f38-ac0d-4f9d-a1b1-017082f8c831" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_27c7530d-4d97-4eb5-8965-2b76e3b33520" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_dcd6ed7b-0073-4f75-9468-b11f337014b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_893a2f38-ac0d-4f9d-a1b1-017082f8c831" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_dcd6ed7b-0073-4f75-9468-b11f337014b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_c07d132a-018a-46e7-9446-4c4ad7d40727" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_893a2f38-ac0d-4f9d-a1b1-017082f8c831" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_c07d132a-018a-46e7-9446-4c4ad7d40727" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_b4598d47-94c2-4148-8349-df224229cc7c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_893a2f38-ac0d-4f9d-a1b1-017082f8c831" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_b4598d47-94c2-4148-8349-df224229cc7c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_1fa30385-d0e1-455d-a891-b18c4b9e6311" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_f97dcb82-213a-464b-a028-d3cbcf550525" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_24ca9fa8-f6e4-46db-b5de-16e31f3a1820" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_f97dcb82-213a-464b-a028-d3cbcf550525" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_793b4a32-ab1c-4871-99f0-1b742f503ac6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_f97dcb82-213a-464b-a028-d3cbcf550525" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_793b4a32-ab1c-4871-99f0-1b742f503ac6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_bf8079b5-01b5-4e36-8e6f-2d69b0535a93" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_f97dcb82-213a-464b-a028-d3cbcf550525" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_bf8079b5-01b5-4e36-8e6f-2d69b0535a93" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_d155151c-6ed7-456d-8e44-015ea4af3ba5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_f97dcb82-213a-464b-a028-d3cbcf550525" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_d155151c-6ed7-456d-8e44-015ea4af3ba5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_3cec3e4f-02b0-48e2-ad0b-dad196ed6779" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_f97dcb82-213a-464b-a028-d3cbcf550525" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_3cec3e4f-02b0-48e2-ad0b-dad196ed6779" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_dc988c9f-1d6b-45d7-9296-4c70475c6d0f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentOtherThanOptionsVestedInPeriodIntrinsicValue_93b59a07-2f21-4e74-bf47-907fb6c2e30a" xlink:href="unfi-20250802.xsd#unfi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentOtherThanOptionsVestedInPeriodIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_24ca9fa8-f6e4-46db-b5de-16e31f3a1820" xlink:to="loc_unfi_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentOtherThanOptionsVestedInPeriodIntrinsicValue_93b59a07-2f21-4e74-bf47-907fb6c2e30a" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/SHAREBASEDAWARDSPerformanceBasedShareAwardsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#SHAREBASEDAWARDSPerformanceBasedShareAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/SHAREBASEDAWARDSPerformanceBasedShareAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8ead8b77-d69d-49ab-9903-4b4b41f0ace3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dd045734-f142-4cd6-ab65-0ea939b5a6ae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8ead8b77-d69d-49ab-9903-4b4b41f0ace3" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dd045734-f142-4cd6-ab65-0ea939b5a6ae" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_2c5d21a9-850d-4da2-b04e-9587205a310d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dd045734-f142-4cd6-ab65-0ea939b5a6ae" xlink:to="loc_us-gaap_AwardTypeAxis_2c5d21a9-850d-4da2-b04e-9587205a310d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2c5d21a9-850d-4da2-b04e-9587205a310d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_2c5d21a9-850d-4da2-b04e-9587205a310d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_2c5d21a9-850d-4da2-b04e-9587205a310d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a9371a67-5d66-4c5d-a58a-4b3e891f5df2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_2c5d21a9-850d-4da2-b04e-9587205a310d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a9371a67-5d66-4c5d-a58a-4b3e891f5df2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_d15b2260-3844-404a-acc9-62f76b333881" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a9371a67-5d66-4c5d-a58a-4b3e891f5df2" xlink:to="loc_us-gaap_PerformanceSharesMember_d15b2260-3844-404a-acc9-62f76b333881" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_e6ffb625-9cd8-4562-b518-a523e31771e0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8ead8b77-d69d-49ab-9903-4b4b41f0ace3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_e6ffb625-9cd8-4562-b518-a523e31771e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_73d22c96-f161-4f9a-a09d-c3d16e49be4f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8ead8b77-d69d-49ab-9903-4b4b41f0ace3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_73d22c96-f161-4f9a-a09d-c3d16e49be4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_49218444-7adc-4a17-b1da-baec8aef93d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_8ead8b77-d69d-49ab-9903-4b4b41f0ace3" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_49218444-7adc-4a17-b1da-baec8aef93d9" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSNarrativeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_ebfb9aa3-230a-4b4f-9b35-8ac58e4534a9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_43ca6209-7266-440e-8e53-75cdddc2ed4b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_ebfb9aa3-230a-4b4f-9b35-8ac58e4534a9" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_43ca6209-7266-440e-8e53-75cdddc2ed4b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameAxis_ae52fa8c-1bed-4fc8-a3df-e4b472e3b18c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_43ca6209-7266-440e-8e53-75cdddc2ed4b" xlink:to="loc_us-gaap_RetirementPlanNameAxis_ae52fa8c-1bed-4fc8-a3df-e4b472e3b18c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_ae52fa8c-1bed-4fc8-a3df-e4b472e3b18c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanNameAxis_ae52fa8c-1bed-4fc8-a3df-e4b472e3b18c" xlink:to="loc_us-gaap_RetirementPlanNameDomain_ae52fa8c-1bed-4fc8-a3df-e4b472e3b18c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_7b1f66c3-b34f-4205-88e7-f3ccb07a2461" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanNameAxis_ae52fa8c-1bed-4fc8-a3df-e4b472e3b18c" xlink:to="loc_us-gaap_RetirementPlanNameDomain_7b1f66c3-b34f-4205-88e7-f3ccb07a2461" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_SupervaluRetirementPlanMember_ceec35bf-b7ef-426d-88e7-b5b80b30f428" xlink:href="unfi-20250802.xsd#unfi_SupervaluRetirementPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_7b1f66c3-b34f-4205-88e7-f3ccb07a2461" xlink:to="loc_unfi_SupervaluRetirementPlanMember_ceec35bf-b7ef-426d-88e7-b5b80b30f428" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationChangeInDiscountRate_0dce986d-2480-4188-9da4-ff3ef9673aca" xlink:href="unfi-20250802.xsd#unfi_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationChangeInDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_ebfb9aa3-230a-4b4f-9b35-8ac58e4534a9" xlink:to="loc_unfi_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationChangeInDiscountRate_0dce986d-2480-4188-9da4-ff3ef9673aca" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSDefinedBenefitPensionPlansDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSDefinedBenefitPensionPlansDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSDefinedBenefitPensionPlansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bf9628a6-0416-4783-b555-efe0fa801ec1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_08452da1-f9e4-442a-b750-76b05535b88e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bf9628a6-0416-4783-b555-efe0fa801ec1" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_08452da1-f9e4-442a-b750-76b05535b88e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_cd7649f5-da26-4c17-bb60-1b106784c3a7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_08452da1-f9e4-442a-b750-76b05535b88e" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_cd7649f5-da26-4c17-bb60-1b106784c3a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_cd7649f5-da26-4c17-bb60-1b106784c3a7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_cd7649f5-da26-4c17-bb60-1b106784c3a7" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_cd7649f5-da26-4c17-bb60-1b106784c3a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_b4b271d3-b431-4a27-ae98-bb26da3731c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_cd7649f5-da26-4c17-bb60-1b106784c3a7" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_b4b271d3-b431-4a27-ae98-bb26da3731c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_25766369-d15a-4bbe-86f2-5502991dc06d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_b4b271d3-b431-4a27-ae98-bb26da3731c7" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_25766369-d15a-4bbe-86f2-5502991dc06d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_a2992555-4c40-4930-be22-1423e5acc3f9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_b4b271d3-b431-4a27-ae98-bb26da3731c7" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_a2992555-4c40-4930-be22-1423e5acc3f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_8d62d25d-bd58-4e10-93dc-56a209fcfca9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bf9628a6-0416-4783-b555-efe0fa801ec1" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_8d62d25d-bd58-4e10-93dc-56a209fcfca9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_a1324147-4629-4841-81c7-c6a67823a313" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_8d62d25d-bd58-4e10-93dc-56a209fcfca9" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_a1324147-4629-4841-81c7-c6a67823a313" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_1b466a7b-1071-47ef-8a69-1dc7dd59935b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_8d62d25d-bd58-4e10-93dc-56a209fcfca9" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_1b466a7b-1071-47ef-8a69-1dc7dd59935b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_11aee59b-7ff8-4aae-81ec-2c9165de73ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_8d62d25d-bd58-4e10-93dc-56a209fcfca9" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_11aee59b-7ff8-4aae-81ec-2c9165de73ab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_c558117b-cad3-427a-a9ed-7fdc7f768731" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_8d62d25d-bd58-4e10-93dc-56a209fcfca9" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_c558117b-cad3-427a-a9ed-7fdc7f768731" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_b159ca3d-d4c5-4484-8632-d42f2df17d43" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_981a8c43-329b-4320-a357-fc175e24c0f8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bf9628a6-0416-4783-b555-efe0fa801ec1" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_981a8c43-329b-4320-a357-fc175e24c0f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_2afd7a95-433a-4697-9dd0-24dea3ce3daa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_981a8c43-329b-4320-a357-fc175e24c0f8" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_2afd7a95-433a-4697-9dd0-24dea3ce3daa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_2cc635da-51eb-4089-9cbc-0d8bd013f129" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_981a8c43-329b-4320-a357-fc175e24c0f8" xlink:to="loc_us-gaap_DefinedBenefitPlanActualReturnOnPlanAssets_2cc635da-51eb-4089-9cbc-0d8bd013f129" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_68fb876c-4ca6-4790-9491-2c54b7b7c881" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_981a8c43-329b-4320-a357-fc175e24c0f8" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsBenefitsPaid_68fb876c-4ca6-4790-9491-2c54b7b7c881" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_5502809a-5143-4a92-8dbf-bdf684c2fd73" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanContributionsByEmployer"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInFairValueOfPlanAssetsRollForward_981a8c43-329b-4320-a357-fc175e24c0f8" xlink:to="loc_us-gaap_DefinedBenefitPlanContributionsByEmployer_5502809a-5143-4a92-8dbf-bdf684c2fd73" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_13f03ab1-0acc-4cf1-b0c3-197b442feaec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_988947a1-9013-4cf3-8fe7-0dee94a2508b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_bf9628a6-0416-4783-b555-efe0fa801ec1" xlink:to="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_988947a1-9013-4cf3-8fe7-0dee94a2508b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSFairValueofPlanAssetsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSFairValueofPlanAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSFairValueofPlanAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6b268c00-d895-45c6-887e-0dd021d70999" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_ec307f93-2b43-43a1-9efd-0ad2e1a6fa39" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6b268c00-d895-45c6-887e-0dd021d70999" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_ec307f93-2b43-43a1-9efd-0ad2e1a6fa39" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameAxis_9ddd28de-2e27-408c-a0b0-d5c627bf9ccc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_ec307f93-2b43-43a1-9efd-0ad2e1a6fa39" xlink:to="loc_us-gaap_RetirementPlanNameAxis_9ddd28de-2e27-408c-a0b0-d5c627bf9ccc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_9ddd28de-2e27-408c-a0b0-d5c627bf9ccc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanNameAxis_9ddd28de-2e27-408c-a0b0-d5c627bf9ccc" xlink:to="loc_us-gaap_RetirementPlanNameDomain_9ddd28de-2e27-408c-a0b0-d5c627bf9ccc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_06e4f331-18d9-4d6b-9446-e79f619f55af" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanNameAxis_9ddd28de-2e27-408c-a0b0-d5c627bf9ccc" xlink:to="loc_us-gaap_RetirementPlanNameDomain_06e4f331-18d9-4d6b-9446-e79f619f55af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_SUPERVALUINCRetirementPlanMember_9b2c3c7f-7513-4f6d-9ee3-a5dae19be46a" xlink:href="unfi-20250802.xsd#unfi_SUPERVALUINCRetirementPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_06e4f331-18d9-4d6b-9446-e79f619f55af" xlink:to="loc_unfi_SUPERVALUINCRetirementPlanMember_9b2c3c7f-7513-4f6d-9ee3-a5dae19be46a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_OtherPensionPlansMember_06a8968d-e9a4-4f92-8190-a078741bba82" xlink:href="unfi-20250802.xsd#unfi_OtherPensionPlansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_06e4f331-18d9-4d6b-9446-e79f619f55af" xlink:to="loc_unfi_OtherPensionPlansMember_06a8968d-e9a4-4f92-8190-a078741bba82" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_74b72885-aaeb-4f8f-91b4-a0f4a3747824" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_ec307f93-2b43-43a1-9efd-0ad2e1a6fa39" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_74b72885-aaeb-4f8f-91b4-a0f4a3747824" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_74b72885-aaeb-4f8f-91b4-a0f4a3747824_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_74b72885-aaeb-4f8f-91b4-a0f4a3747824" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_74b72885-aaeb-4f8f-91b4-a0f4a3747824_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_2bb45b9d-7e3a-40e9-8ad7-c1e2ff96ff1f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_74b72885-aaeb-4f8f-91b4-a0f4a3747824" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_2bb45b9d-7e3a-40e9-8ad7-c1e2ff96ff1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_24d6d168-4e47-4380-9b7b-0421971ae886" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_2bb45b9d-7e3a-40e9-8ad7-c1e2ff96ff1f" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_24d6d168-4e47-4380-9b7b-0421971ae886" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_500076dc-aa41-4069-8505-b5d1060be26c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6b268c00-d895-45c6-887e-0dd021d70999" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_500076dc-aa41-4069-8505-b5d1060be26c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_1a01051b-19e2-4d50-9210-bba2de554539" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6b268c00-d895-45c6-887e-0dd021d70999" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_1a01051b-19e2-4d50-9210-bba2de554539" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_58431ff5-103f-4b88-afa1-7859d75cbb48" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_6b268c00-d895-45c6-887e-0dd021d70999" xlink:to="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_58431ff5-103f-4b88-afa1-7859d75cbb48" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSNetPeriodicBenefitIncomeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSNetPeriodicBenefitIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSNetPeriodicBenefitIncomeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_34c04a7a-4df8-4d3b-bea5-bb9f790fd4d9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_7f01c66f-7582-4ac9-80e8-623ff50403d6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_34c04a7a-4df8-4d3b-bea5-bb9f790fd4d9" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_7f01c66f-7582-4ac9-80e8-623ff50403d6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_ccf57f1a-5d24-4946-a4c8-c494c7d967d3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_7f01c66f-7582-4ac9-80e8-623ff50403d6" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_ccf57f1a-5d24-4946-a4c8-c494c7d967d3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_ccf57f1a-5d24-4946-a4c8-c494c7d967d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_ccf57f1a-5d24-4946-a4c8-c494c7d967d3" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_ccf57f1a-5d24-4946-a4c8-c494c7d967d3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_e9d228fa-e8cc-42a0-bf23-c7dc7d97cbb7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_ccf57f1a-5d24-4946-a4c8-c494c7d967d3" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_e9d228fa-e8cc-42a0-bf23-c7dc7d97cbb7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_55404630-7feb-4919-9b9f-b7cb96125ac8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_e9d228fa-e8cc-42a0-bf23-c7dc7d97cbb7" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_55404630-7feb-4919-9b9f-b7cb96125ac8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_6e180457-0cba-4858-b8f2-15a337bf73a8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_e9d228fa-e8cc-42a0-bf23-c7dc7d97cbb7" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_6e180457-0cba-4858-b8f2-15a337bf73a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_34c04a7a-4df8-4d3b-bea5-bb9f790fd4d9" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_b7bdc408-a626-4e1f-b8d9-6911989bc60d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets_b7bdc408-a626-4e1f-b8d9-6911989bc60d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_bd031ac3-2bc7-4d1b-94c7-395a7f3710df" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_bd031ac3-2bc7-4d1b-94c7-395a7f3710df" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_0b665574-37b8-490d-83ea-78866e0dd5f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_0b665574-37b8-490d-83ea-78866e0dd5f6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_5ae7c61e-d5b7-46f5-99e7-00843a557b3a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_5ae7c61e-d5b7-46f5-99e7-00843a557b3a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_ee3c5285-2775-4b36-b906-48147400be12" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_ee3c5285-2775-4b36-b906-48147400be12" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_e1b29048-cbb1-4b61-bb93-f6da4f9552f7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditExpectedReturnLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_e1b29048-cbb1-4b61-bb93-f6da4f9552f7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList_e53af15e-cddf-4823-a3d7-36a7e109ceb6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditInterestCostStatementOfIncomeOrComprehensiveIncomeExtensibleList_e53af15e-cddf-4823-a3d7-36a7e109ceb6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfPriorServiceCostCreditStatementOfIncomeOrComprehensiveIncomeExtensibleList_eeecef8a-2263-4cf7-8d25-0a7566d35a09" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfPriorServiceCostCreditStatementOfIncomeOrComprehensiveIncomeExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfPriorServiceCostCreditStatementOfIncomeOrComprehensiveIncomeExtensibleList_eeecef8a-2263-4cf7-8d25-0a7566d35a09" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_a384fa4f-5569-4907-94c4-75ce151655ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract_8627f88f-4b83-47de-bc8e-164a06390246" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostCreditAmortizationOfGainLossStatementOfIncomeOrComprehensiveIncomeExtensibleList_a384fa4f-5569-4907-94c4-75ce151655ea" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeAbstract_d0a7e86d-eb43-4750-aa04-891f8e41fc07" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_34c04a7a-4df8-4d3b-bea5-bb9f790fd4d9" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeAbstract_d0a7e86d-eb43-4750-aa04-891f8e41fc07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax_9f89302a-0c8a-4450-8f4e-8bb650221ecb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeAbstract_d0a7e86d-eb43-4750-aa04-891f8e41fc07" xlink:to="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax_9f89302a-0c8a-4450-8f4e-8bb650221ecb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax_31f4e516-164a-4c22-a048-954a6d9cbc2f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeAbstract_d0a7e86d-eb43-4750-aa04-891f8e41fc07" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansNetUnamortizedGainLossArisingDuringPeriodBeforeTax_31f4e516-164a-4c22-a048-954a6d9cbc2f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_OtherComprehensiveIncomeLossDefinedBenefitPlanAmortizationOfNetActuarialLoss_b8bb3cfd-d72a-484f-8d36-d0ef67d480c9" xlink:href="unfi-20250802.xsd#unfi_OtherComprehensiveIncomeLossDefinedBenefitPlanAmortizationOfNetActuarialLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeAbstract_d0a7e86d-eb43-4750-aa04-891f8e41fc07" xlink:to="loc_unfi_OtherComprehensiveIncomeLossDefinedBenefitPlanAmortizationOfNetActuarialLoss_b8bb3cfd-d72a-484f-8d36-d0ef67d480c9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax_4087f7d9-df3b-4d43-8b6b-02c9b36c3696" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeAbstract_d0a7e86d-eb43-4750-aa04-891f8e41fc07" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax_4087f7d9-df3b-4d43-8b6b-02c9b36c3696" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax_f640b21f-175b-4df0-ba31-589e2eeb1719" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeAbstract_d0a7e86d-eb43-4750-aa04-891f8e41fc07" xlink:to="loc_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax_f640b21f-175b-4df0-ba31-589e2eeb1719" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSAmountsRecognizedinConsolidatedBalanceSheetsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSAmountsRecognizedinConsolidatedBalanceSheetsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSAmountsRecognizedinConsolidatedBalanceSheetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_38ec0521-c2b8-4403-adb1-652068d8f799" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_153aa69d-2da8-472e-9b15-cc85183a4c24" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_38ec0521-c2b8-4403-adb1-652068d8f799" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_153aa69d-2da8-472e-9b15-cc85183a4c24" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_b8c92c3a-f5c1-4e26-8992-b2f84089ae5e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_153aa69d-2da8-472e-9b15-cc85183a4c24" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_b8c92c3a-f5c1-4e26-8992-b2f84089ae5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_b8c92c3a-f5c1-4e26-8992-b2f84089ae5e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_b8c92c3a-f5c1-4e26-8992-b2f84089ae5e" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_b8c92c3a-f5c1-4e26-8992-b2f84089ae5e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_2fe12306-dbb1-4e21-84ef-b987cf9f279e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_b8c92c3a-f5c1-4e26-8992-b2f84089ae5e" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_2fe12306-dbb1-4e21-84ef-b987cf9f279e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_0e53ad4e-73ad-403b-b466-1b5fcfdd88ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_2fe12306-dbb1-4e21-84ef-b987cf9f279e" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_0e53ad4e-73ad-403b-b466-1b5fcfdd88ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_4d7f9215-e1d0-402a-b36f-2a49e40f6ec6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_2fe12306-dbb1-4e21-84ef-b987cf9f279e" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_4d7f9215-e1d0-402a-b36f-2a49e40f6ec6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_6e8e52db-85bc-4971-9307-3d1a0f8832a1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_38ec0521-c2b8-4403-adb1-652068d8f799" xlink:to="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_6e8e52db-85bc-4971-9307-3d1a0f8832a1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_5a85b9ae-b08a-4d41-9be4-35b3ae11186d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_38ec0521-c2b8-4403-adb1-652068d8f799" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_5a85b9ae-b08a-4d41-9be4-35b3ae11186d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_a2b9a622-139f-4da8-9847-0b34e348de13" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_38ec0521-c2b8-4403-adb1-652068d8f799" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_a2b9a622-139f-4da8-9847-0b34e348de13" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_3902ae9c-fc05-44b0-861e-53a5c78a3611" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_38ec0521-c2b8-4403-adb1-652068d8f799" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_3902ae9c-fc05-44b0-861e-53a5c78a3611" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSBenefitPlanAssumptionsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSBenefitPlanAssumptionsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSBenefitPlanAssumptionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_59c53ba2-c28b-4122-862d-e48e45e7446a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_9850b589-3ffe-4a32-8e60-e8c5b278c223" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_59c53ba2-c28b-4122-862d-e48e45e7446a" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_9850b589-3ffe-4a32-8e60-e8c5b278c223" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_bbc5361b-6383-45ab-bf06-e0bd0dbce423" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_9850b589-3ffe-4a32-8e60-e8c5b278c223" xlink:to="loc_srt_RangeAxis_bbc5361b-6383-45ab-bf06-e0bd0dbce423" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_bbc5361b-6383-45ab-bf06-e0bd0dbce423_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_bbc5361b-6383-45ab-bf06-e0bd0dbce423" xlink:to="loc_srt_RangeMember_bbc5361b-6383-45ab-bf06-e0bd0dbce423_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_3f7fd485-4c11-4330-930d-35666f5b24db" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_bbc5361b-6383-45ab-bf06-e0bd0dbce423" xlink:to="loc_srt_RangeMember_3f7fd485-4c11-4330-930d-35666f5b24db" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_9499c3ab-ec14-4bc5-a8d8-928c51131015" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3f7fd485-4c11-4330-930d-35666f5b24db" xlink:to="loc_srt_MinimumMember_9499c3ab-ec14-4bc5-a8d8-928c51131015" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_606cdebf-0a85-49d4-9c33-4a2c9ea2678c" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_3f7fd485-4c11-4330-930d-35666f5b24db" xlink:to="loc_srt_MaximumMember_606cdebf-0a85-49d4-9c33-4a2c9ea2678c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RetirementPlanAgeAxis_2592bfd2-fbbe-491a-934a-0ae1c30400f8" xlink:href="unfi-20250802.xsd#unfi_RetirementPlanAgeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_9850b589-3ffe-4a32-8e60-e8c5b278c223" xlink:to="loc_unfi_RetirementPlanAgeAxis_2592bfd2-fbbe-491a-934a-0ae1c30400f8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RetirementPlanAgeDomain_2592bfd2-fbbe-491a-934a-0ae1c30400f8_default" xlink:href="unfi-20250802.xsd#unfi_RetirementPlanAgeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_unfi_RetirementPlanAgeAxis_2592bfd2-fbbe-491a-934a-0ae1c30400f8" xlink:to="loc_unfi_RetirementPlanAgeDomain_2592bfd2-fbbe-491a-934a-0ae1c30400f8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RetirementPlanAgeDomain_1123a100-729c-4a38-af2c-867c805264ae" xlink:href="unfi-20250802.xsd#unfi_RetirementPlanAgeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_unfi_RetirementPlanAgeAxis_2592bfd2-fbbe-491a-934a-0ae1c30400f8" xlink:to="loc_unfi_RetirementPlanAgeDomain_1123a100-729c-4a38-af2c-867c805264ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RetirementPlanBeforeAge65Member_8b39d9a5-9725-4f29-97a4-1cb82d6a3e55" xlink:href="unfi-20250802.xsd#unfi_RetirementPlanBeforeAge65Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_RetirementPlanAgeDomain_1123a100-729c-4a38-af2c-867c805264ae" xlink:to="loc_unfi_RetirementPlanBeforeAge65Member_8b39d9a5-9725-4f29-97a4-1cb82d6a3e55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RetirementPlanAfterAge65Member_1ab16af7-f672-4288-b253-c0e2181a0e77" xlink:href="unfi-20250802.xsd#unfi_RetirementPlanAfterAge65Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_unfi_RetirementPlanAgeDomain_1123a100-729c-4a38-af2c-867c805264ae" xlink:to="loc_unfi_RetirementPlanAfterAge65Member_1ab16af7-f672-4288-b253-c0e2181a0e77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_6a0b1c4c-5541-4bd3-87b4-197b734123ab" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_9850b589-3ffe-4a32-8e60-e8c5b278c223" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_6a0b1c4c-5541-4bd3-87b4-197b734123ab" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_6a0b1c4c-5541-4bd3-87b4-197b734123ab_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_6a0b1c4c-5541-4bd3-87b4-197b734123ab" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_6a0b1c4c-5541-4bd3-87b4-197b734123ab_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_89a803c8-2d46-4128-88c4-4d8f7ad2c9ec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_6a0b1c4c-5541-4bd3-87b4-197b734123ab" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_89a803c8-2d46-4128-88c4-4d8f7ad2c9ec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PostemploymentRetirementBenefitsMember_8ed4171e-1523-4228-a846-5b3ec48d427e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PostemploymentRetirementBenefitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_89a803c8-2d46-4128-88c4-4d8f7ad2c9ec" xlink:to="loc_us-gaap_PostemploymentRetirementBenefitsMember_8ed4171e-1523-4228-a846-5b3ec48d427e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_f7e53e1f-afe2-443f-bf01-521d0afee777" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_59c53ba2-c28b-4122-862d-e48e45e7446a" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_f7e53e1f-afe2-443f-bf01-521d0afee777" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_15a6dc24-2f72-4dbb-a7a2-a43582a20ef1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_f7e53e1f-afe2-443f-bf01-521d0afee777" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_15a6dc24-2f72-4dbb-a7a2-a43582a20ef1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_91847be6-25cf-43ba-9fb8-a0d985b41bf7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_59c53ba2-c28b-4122-862d-e48e45e7446a" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_91847be6-25cf-43ba-9fb8-a0d985b41bf7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_63330078-1801-43fb-9c8b-580112af0fd2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_91847be6-25cf-43ba-9fb8-a0d985b41bf7" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate_63330078-1801-43fb-9c8b-580112af0fd2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_f96d4606-b686-43cd-a712-085886954daa" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_91847be6-25cf-43ba-9fb8-a0d985b41bf7" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease_f96d4606-b686-43cd-a712-085886954daa" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_2d20eb17-5790-4d1a-bf4a-28873b591e5f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_91847be6-25cf-43ba-9fb8-a0d985b41bf7" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets_2d20eb17-5790-4d1a-bf4a-28873b591e5f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRate_09981abc-f0d5-406a-a818-8bcc86ce9627" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingNetPeriodicBenefitCostAbstract_91847be6-25cf-43ba-9fb8-a0d985b41bf7" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostWeightedAverageInterestCreditingRate_09981abc-f0d5-406a-a818-8bcc86ce9627" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DefinedBenefitPlanHealthCareCostTrendRateAssumed_38176efc-f590-4ca4-8a91-23f811717f3a" xlink:href="unfi-20250802.xsd#unfi_DefinedBenefitPlanHealthCareCostTrendRateAssumed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_59c53ba2-c28b-4122-862d-e48e45e7446a" xlink:to="loc_unfi_DefinedBenefitPlanHealthCareCostTrendRateAssumed_38176efc-f590-4ca4-8a91-23f811717f3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1_5e1bbe2f-e86d-4511-843a-74c342596eed" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_59c53ba2-c28b-4122-862d-e48e45e7446a" xlink:to="loc_us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1_5e1bbe2f-e86d-4511-843a-74c342596eed" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSAllocationofPensionPlanAssetsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSAllocationofPensionPlanAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSAllocationofPensionPlanAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_3eb232bf-8da3-400a-8f44-d7d19dcc31a3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_3003cca4-9d28-4a08-a6e6-b301cf52bac9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_3eb232bf-8da3-400a-8f44-d7d19dcc31a3" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_3003cca4-9d28-4a08-a6e6-b301cf52bac9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_5d27205a-1d0d-44e5-9083-d0795e5a7142" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_3003cca4-9d28-4a08-a6e6-b301cf52bac9" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_5d27205a-1d0d-44e5-9083-d0795e5a7142" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_5d27205a-1d0d-44e5-9083-d0795e5a7142_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_5d27205a-1d0d-44e5-9083-d0795e5a7142" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_5d27205a-1d0d-44e5-9083-d0795e5a7142_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_488faa89-ef80-404f-8202-8f0429295bff" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_5d27205a-1d0d-44e5-9083-d0795e5a7142" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_488faa89-ef80-404f-8202-8f0429295bff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedIncomeFundsMember_1e7f7518-39b4-446b-bd08-df4cb29bccc8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FixedIncomeFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_488faa89-ef80-404f-8202-8f0429295bff" xlink:to="loc_us-gaap_FixedIncomeFundsMember_1e7f7518-39b4-446b-bd08-df4cb29bccc8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_4c2566e2-a7b4-4514-8179-119a355965b3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_488faa89-ef80-404f-8202-8f0429295bff" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesUsMember_4c2566e2-a7b4-4514-8179-119a355965b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrivateEquityFundsMember_2bfc2040-1485-4d61-bd75-536b84b29737" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PrivateEquityFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_488faa89-ef80-404f-8202-8f0429295bff" xlink:to="loc_us-gaap_PrivateEquityFundsMember_2bfc2040-1485-4d61-bd75-536b84b29737" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember_731e786b-6449-4541-a4cb-a93e63f4c6cd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_488faa89-ef80-404f-8202-8f0429295bff" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesNonUsMember_731e786b-6449-4541-a4cb-a93e63f4c6cd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanRealEstateMember_07dcb49c-5c0f-42ed-b4d7-a0d42a1eb4b5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_488faa89-ef80-404f-8202-8f0429295bff" xlink:to="loc_us-gaap_DefinedBenefitPlanRealEstateMember_07dcb49c-5c0f-42ed-b4d7-a0d42a1eb4b5" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_216fc39f-4205-42af-b807-8c989f5d025e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_3eb232bf-8da3-400a-8f44-d7d19dcc31a3" xlink:to="loc_us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage_216fc39f-4205-42af-b807-8c989f5d025e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_8af3f06c-8296-4536-9963-cf7f25d2b217" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_3eb232bf-8da3-400a-8f44-d7d19dcc31a3" xlink:to="loc_us-gaap_DefinedBenefitPlanWeightedAverageAssetAllocations_8af3f06c-8296-4536-9963-cf7f25d2b217" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSFairValueofDefinedBenefitPensionPlansAssetsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSFairValueofDefinedBenefitPensionPlansAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSFairValueofDefinedBenefitPensionPlansAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_f9b2cf97-15bc-4cb0-9c91-c9ba01c23264" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f3d3341c-3afd-4564-a530-c17b140c0ecf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_f9b2cf97-15bc-4cb0-9c91-c9ba01c23264" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f3d3341c-3afd-4564-a530-c17b140c0ecf" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_a4247c85-f94f-4bd0-bcb0-8f45f5eabac8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f3d3341c-3afd-4564-a530-c17b140c0ecf" xlink:to="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_a4247c85-f94f-4bd0-bcb0-8f45f5eabac8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_a4247c85-f94f-4bd0-bcb0-8f45f5eabac8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_a4247c85-f94f-4bd0-bcb0-8f45f5eabac8" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_a4247c85-f94f-4bd0-bcb0-8f45f5eabac8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanAssetCategoriesDomain_625d6101-0859-4794-a7fc-5ce4691ece5f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PlanAssetCategoriesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_a4247c85-f94f-4bd0-bcb0-8f45f5eabac8" xlink:to="loc_us-gaap_PlanAssetCategoriesDomain_625d6101-0859-4794-a7fc-5ce4691ece5f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesMember_455f4702-da1c-49a9-94df-464b6e7c6fa2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanEquitySecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_625d6101-0859-4794-a7fc-5ce4691ece5f" xlink:to="loc_us-gaap_DefinedBenefitPlanEquitySecuritiesMember_455f4702-da1c-49a9-94df-464b6e7c6fa2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember_8d0f4518-c634-46db-8535-60ee31b25db8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_625d6101-0859-4794-a7fc-5ce4691ece5f" xlink:to="loc_us-gaap_DefinedBenefitPlanCommonCollectiveTrustMember_8d0f4518-c634-46db-8535-60ee31b25db8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_d5fc8d43-9ca6-4634-a891-6c97d61747dd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_625d6101-0859-4794-a7fc-5ce4691ece5f" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_d5fc8d43-9ca6-4634-a891-6c97d61747dd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USTreasuryAndGovernmentMember_782c1ae0-d7ec-4165-88fe-e4327a51156e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_USTreasuryAndGovernmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_625d6101-0859-4794-a7fc-5ce4691ece5f" xlink:to="loc_us-gaap_USTreasuryAndGovernmentMember_782c1ae0-d7ec-4165-88fe-e4327a51156e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageBackedSecuritiesMember_50da54eb-1b0e-492c-84b6-94043de9e903" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MortgageBackedSecuritiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_625d6101-0859-4794-a7fc-5ce4691ece5f" xlink:to="loc_us-gaap_MortgageBackedSecuritiesMember_50da54eb-1b0e-492c-84b6-94043de9e903" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAggregatedInvestmentsMember_dab9b844-16d7-47b8-8258-b8d57ce0330c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherAggregatedInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_625d6101-0859-4794-a7fc-5ce4691ece5f" xlink:to="loc_us-gaap_OtherAggregatedInvestmentsMember_dab9b844-16d7-47b8-8258-b8d57ce0330c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_PrivateEquityFundsAndRealEstateMember_50eb28ba-7992-4c7d-a3b8-78b7c2627ed5" xlink:href="unfi-20250802.xsd#unfi_PrivateEquityFundsAndRealEstateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanAssetCategoriesDomain_625d6101-0859-4794-a7fc-5ce4691ece5f" xlink:to="loc_unfi_PrivateEquityFundsAndRealEstateMember_50eb28ba-7992-4c7d-a3b8-78b7c2627ed5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d050fdf4-d998-437d-b8c5-d119d10ddb8b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f3d3341c-3afd-4564-a530-c17b140c0ecf" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d050fdf4-d998-437d-b8c5-d119d10ddb8b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d050fdf4-d998-437d-b8c5-d119d10ddb8b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d050fdf4-d998-437d-b8c5-d119d10ddb8b" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d050fdf4-d998-437d-b8c5-d119d10ddb8b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f0ad2ef-dfd0-46f8-a0cc-3c2ba4774811" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_d050fdf4-d998-437d-b8c5-d119d10ddb8b" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f0ad2ef-dfd0-46f8-a0cc-3c2ba4774811" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_c730455c-d032-4e24-935e-1231e5b45010" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f0ad2ef-dfd0-46f8-a0cc-3c2ba4774811" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_c730455c-d032-4e24-935e-1231e5b45010" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_8064e709-a4a6-452a-aa23-f2f84ce2769a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f0ad2ef-dfd0-46f8-a0cc-3c2ba4774811" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_8064e709-a4a6-452a-aa23-f2f84ce2769a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_89e2671c-134e-480e-9f7e-0d7074721008" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f0ad2ef-dfd0-46f8-a0cc-3c2ba4774811" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_89e2671c-134e-480e-9f7e-0d7074721008" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_85586a9e-d96d-474f-ae78-452616fbe7c4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_3f0ad2ef-dfd0-46f8-a0cc-3c2ba4774811" xlink:to="loc_us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember_85586a9e-d96d-474f-ae78-452616fbe7c4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_0ef737b6-f123-4ea5-9faf-6c225d103061" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_f9b2cf97-15bc-4cb0-9c91-c9ba01c23264" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_0ef737b6-f123-4ea5-9faf-6c225d103061" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSContributionsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSContributionsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSContributionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_dbe2ebf4-9b05-497c-80bf-ffba7fd18fdc" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_8eceacb9-8bd5-4a58-be39-0d58a1c27be8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_dbe2ebf4-9b05-497c-80bf-ffba7fd18fdc" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_8eceacb9-8bd5-4a58-be39-0d58a1c27be8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_d27c58a9-1bba-48f5-a535-a373bac3dd89" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_8eceacb9-8bd5-4a58-be39-0d58a1c27be8" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_d27c58a9-1bba-48f5-a535-a373bac3dd89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_d27c58a9-1bba-48f5-a535-a373bac3dd89_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_d27c58a9-1bba-48f5-a535-a373bac3dd89" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_d27c58a9-1bba-48f5-a535-a373bac3dd89_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_b871e794-328c-46ce-8527-2d8c6b325b14" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_d27c58a9-1bba-48f5-a535-a373bac3dd89" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_b871e794-328c-46ce-8527-2d8c6b325b14" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_b96b9670-1a89-412b-a3e9-1c823f05a497" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_b871e794-328c-46ce-8527-2d8c6b325b14" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_b96b9670-1a89-412b-a3e9-1c823f05a497" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_94072301-f28d-4e75-95a6-1d05d5e838eb" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_b871e794-328c-46ce-8527-2d8c6b325b14" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_94072301-f28d-4e75-95a6-1d05d5e838eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsCurrentFiscalYear_8acefa96-c9ce-4718-ac83-be05b68f9426" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsCurrentFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_dbe2ebf4-9b05-497c-80bf-ffba7fd18fdc" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsCurrentFiscalYear_8acefa96-c9ce-4718-ac83-be05b68f9426" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSEstimatedFutureBenefitPaymentsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSEstimatedFutureBenefitPaymentsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSEstimatedFutureBenefitPaymentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_c32273f0-d56e-4120-9074-be0fb8798f5e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_3633ba6b-0c80-443c-97b0-e07430a8890a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_c32273f0-d56e-4120-9074-be0fb8798f5e" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_3633ba6b-0c80-443c-97b0-e07430a8890a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_466aad26-b6ba-40b8-a26b-68e170244338" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_3633ba6b-0c80-443c-97b0-e07430a8890a" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_466aad26-b6ba-40b8-a26b-68e170244338" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_466aad26-b6ba-40b8-a26b-68e170244338_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_466aad26-b6ba-40b8-a26b-68e170244338" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_466aad26-b6ba-40b8-a26b-68e170244338_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_5d73b7ee-51ca-48b3-9dc7-3e1d7707bf35" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_466aad26-b6ba-40b8-a26b-68e170244338" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_5d73b7ee-51ca-48b3-9dc7-3e1d7707bf35" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_b691c970-654f-4321-b1dc-fe9f74c37454" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_5d73b7ee-51ca-48b3-9dc7-3e1d7707bf35" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_b691c970-654f-4321-b1dc-fe9f74c37454" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_8867e1fc-eac3-4d7b-b1b4-ff7896491b1e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_5d73b7ee-51ca-48b3-9dc7-3e1d7707bf35" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_8867e1fc-eac3-4d7b-b1b4-ff7896491b1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_5d8e9b10-15ac-4480-b38c-93aa67e5849b" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_c32273f0-d56e-4120-9074-be0fb8798f5e" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_5d8e9b10-15ac-4480-b38c-93aa67e5849b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_d8ad099b-d783-4984-9139-1e911904e933" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_c32273f0-d56e-4120-9074-be0fb8798f5e" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_d8ad099b-d783-4984-9139-1e911904e933" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_3ba9f06e-018d-49dd-98bb-a03002013f54" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_c32273f0-d56e-4120-9074-be0fb8798f5e" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_3ba9f06e-018d-49dd-98bb-a03002013f54" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_317ba044-4819-45e0-825c-22020f8df862" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_c32273f0-d56e-4120-9074-be0fb8798f5e" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_317ba044-4819-45e0-825c-22020f8df862" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_41a3e7eb-8c7a-4a2d-90de-e226a0225ba4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_c32273f0-d56e-4120-9074-be0fb8798f5e" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_41a3e7eb-8c7a-4a2d-90de-e226a0225ba4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_b34959fe-6bbe-4a4f-bc92-c76a4d09b4de" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_c32273f0-d56e-4120-9074-be0fb8798f5e" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_b34959fe-6bbe-4a4f-bc92-c76a4d09b4de" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSPostEmploymentBenefitsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSPostEmploymentBenefitsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSPostEmploymentBenefitsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_2ea011fc-dca5-49ff-a5eb-b14b69a6e951" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_2bbd5d34-9548-4eb4-81ff-fd3250889dd6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_2ea011fc-dca5-49ff-a5eb-b14b69a6e951" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_2bbd5d34-9548-4eb4-81ff-fd3250889dd6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_8e8b38d1-e4c4-47b4-b414-3b4305040623" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_2bbd5d34-9548-4eb4-81ff-fd3250889dd6" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_8e8b38d1-e4c4-47b4-b414-3b4305040623" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_8e8b38d1-e4c4-47b4-b414-3b4305040623_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_8e8b38d1-e4c4-47b4-b414-3b4305040623" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_8e8b38d1-e4c4-47b4-b414-3b4305040623_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_8d00b354-9f03-4622-8203-39d73a2e4414" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_8e8b38d1-e4c4-47b4-b414-3b4305040623" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_8d00b354-9f03-4622-8203-39d73a2e4414" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PostemploymentRetirementBenefitsMember_5ce55833-6a21-48b3-a0f9-2fe5fe2d3fd9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PostemploymentRetirementBenefitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_8d00b354-9f03-4622-8203-39d73a2e4414" xlink:to="loc_us-gaap_PostemploymentRetirementBenefitsMember_5ce55833-6a21-48b3-a0f9-2fe5fe2d3fd9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_71e2f264-d77e-47ab-bead-4bdc5c533ded" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_2ea011fc-dca5-49ff-a5eb-b14b69a6e951" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_71e2f264-d77e-47ab-bead-4bdc5c533ded" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_e8dc1ea4-6c61-4300-91d9-7169630312e8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_2ea011fc-dca5-49ff-a5eb-b14b69a6e951" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_e8dc1ea4-6c61-4300-91d9-7169630312e8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSMultiemployerPensionPlansNarrativeDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSMultiemployerPensionPlansNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSMultiemployerPensionPlansNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_0185cad0-6547-4f28-b857-1929376edee1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_0185cad0-6547-4f28-b857-1929376edee1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_5ffc74ad-44fb-4b85-aa8d-68c7d8507694" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_0185cad0-6547-4f28-b857-1929376edee1" xlink:to="loc_srt_RangeAxis_5ffc74ad-44fb-4b85-aa8d-68c7d8507694" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_5ffc74ad-44fb-4b85-aa8d-68c7d8507694_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_5ffc74ad-44fb-4b85-aa8d-68c7d8507694" xlink:to="loc_srt_RangeMember_5ffc74ad-44fb-4b85-aa8d-68c7d8507694_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_21941713-ed1e-4fb8-8b9a-95db7c2f6344" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_5ffc74ad-44fb-4b85-aa8d-68c7d8507694" xlink:to="loc_srt_RangeMember_21941713-ed1e-4fb8-8b9a-95db7c2f6344" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_d38ca09e-bf04-4fce-8584-f322f413a9c6" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_21941713-ed1e-4fb8-8b9a-95db7c2f6344" xlink:to="loc_srt_MinimumMember_d38ca09e-bf04-4fce-8584-f322f413a9c6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_adef73df-52e6-4bad-b3e0-d7fd9041f61d" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_21941713-ed1e-4fb8-8b9a-95db7c2f6344" xlink:to="loc_srt_MaximumMember_adef73df-52e6-4bad-b3e0-d7fd9041f61d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_dc0f9f35-6788-40ff-9f74-5012df6939b0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_0185cad0-6547-4f28-b857-1929376edee1" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_dc0f9f35-6788-40ff-9f74-5012df6939b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_dc0f9f35-6788-40ff-9f74-5012df6939b0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_dc0f9f35-6788-40ff-9f74-5012df6939b0" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_dc0f9f35-6788-40ff-9f74-5012df6939b0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_06105587-a737-4a40-8a1e-8821b36d4a8e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_dc0f9f35-6788-40ff-9f74-5012df6939b0" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_06105587-a737-4a40-8a1e-8821b36d4a8e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentLiabilitiesMember_a55ff81e-e376-4db6-a39b-35b9befdff31" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNoncurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_06105587-a737-4a40-8a1e-8821b36d4a8e" xlink:to="loc_us-gaap_OtherNoncurrentLiabilitiesMember_a55ff81e-e376-4db6-a39b-35b9befdff31" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesMember_eee263ca-567f-4a7d-930a-d734e2da0922" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_06105587-a737-4a40-8a1e-8821b36d4a8e" xlink:to="loc_us-gaap_AccruedLiabilitiesMember_eee263ca-567f-4a7d-930a-d734e2da0922" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlanSignificantDeepRedZoneStatusFundingPercentage_c74047ff-96a2-4cab-be64-d1dafd401f25" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlanSignificantDeepRedZoneStatusFundingPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:to="loc_unfi_MultiemployerPlanSignificantDeepRedZoneStatusFundingPercentage_c74047ff-96a2-4cab-be64-d1dafd401f25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlanSignificantDeepRedZoneStatusExpectedInsolventPeriod_4583666e-c49e-4943-b0ae-46bf4f452244" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlanSignificantDeepRedZoneStatusExpectedInsolventPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:to="loc_unfi_MultiemployerPlanSignificantDeepRedZoneStatusExpectedInsolventPeriod_4583666e-c49e-4943-b0ae-46bf4f452244" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlanSignificantRedZoneStatusFundingPercentage_7c93c112-65c2-4cb7-a645-da56ea096036" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlanSignificantRedZoneStatusFundingPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:to="loc_unfi_MultiemployerPlanSignificantRedZoneStatusFundingPercentage_7c93c112-65c2-4cb7-a645-da56ea096036" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlanSignificantYellowZoneStatusFundingPercentage_a4748351-917d-4b93-a3c8-24f050f97803" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlanSignificantYellowZoneStatusFundingPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:to="loc_unfi_MultiemployerPlanSignificantYellowZoneStatusFundingPercentage_a4748351-917d-4b93-a3c8-24f050f97803" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlanSignificantGreenZoneStatusFundingPercentage_e78edb7f-d616-4c50-a0e9-7ef06e26b06c" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlanSignificantGreenZoneStatusFundingPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:to="loc_unfi_MultiemployerPlanSignificantGreenZoneStatusFundingPercentage_e78edb7f-d616-4c50-a0e9-7ef06e26b06c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlansWithdrawalObligation_48b31347-ec9a-487e-afe7-165661530f66" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlansWithdrawalObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:to="loc_us-gaap_MultiemployerPlansWithdrawalObligation_48b31347-ec9a-487e-afe7-165661530f66" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_NumberOfMultiemployerPlans_3abea757-6c7e-43ff-8fcc-e22794bb0b30" xlink:href="unfi-20250802.xsd#unfi_NumberOfMultiemployerPlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:to="loc_unfi_NumberOfMultiemployerPlans_3abea757-6c7e-43ff-8fcc-e22794bb0b30" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlansPaymentPeriod_79be4297-b88c-4d22-b473-6f2baed2b0e2" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlansPaymentPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_36c0986d-5156-4fec-b275-28a6cc3123f7" xlink:to="loc_unfi_MultiemployerPlansPaymentPeriod_79be4297-b88c-4d22-b473-6f2baed2b0e2" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSSignificantMultiemployerPlansDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSSignificantMultiemployerPlansDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSSignificantMultiemployerPlansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8d5789bf-fc0d-4976-a750-cff552d8c3db" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f14c9f93-1381-45f8-9f2f-ce163a6b0149" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8d5789bf-fc0d-4976-a750-cff552d8c3db" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f14c9f93-1381-45f8-9f2f-ce163a6b0149" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameAxis_a366dd9a-2bf9-485c-85dc-94b6c1218e56" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_f14c9f93-1381-45f8-9f2f-ce163a6b0149" xlink:to="loc_us-gaap_RetirementPlanNameAxis_a366dd9a-2bf9-485c-85dc-94b6c1218e56" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_a366dd9a-2bf9-485c-85dc-94b6c1218e56_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanNameAxis_a366dd9a-2bf9-485c-85dc-94b6c1218e56" xlink:to="loc_us-gaap_RetirementPlanNameDomain_a366dd9a-2bf9-485c-85dc-94b6c1218e56_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_c0db1424-438b-4b6f-946e-195ced9d3b6e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanNameAxis_a366dd9a-2bf9-485c-85dc-94b6c1218e56" xlink:to="loc_us-gaap_RetirementPlanNameDomain_c0db1424-438b-4b6f-946e-195ced9d3b6e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MinneapolisFoodDistributingIndustryPensionPlanMember_2d9e7940-5e82-4691-9462-fe81290ae087" xlink:href="unfi-20250802.xsd#unfi_MinneapolisFoodDistributingIndustryPensionPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_c0db1424-438b-4b6f-946e-195ced9d3b6e" xlink:to="loc_unfi_MinneapolisFoodDistributingIndustryPensionPlanMember_2d9e7940-5e82-4691-9462-fe81290ae087" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MinneapolisRetailMeatCuttersAndFoodHandlersPensionFundMember_bbd3b912-c81a-4666-821b-d7339a6bc0e1" xlink:href="unfi-20250802.xsd#unfi_MinneapolisRetailMeatCuttersAndFoodHandlersPensionFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_c0db1424-438b-4b6f-946e-195ced9d3b6e" xlink:to="loc_unfi_MinneapolisRetailMeatCuttersAndFoodHandlersPensionFundMember_bbd3b912-c81a-4666-821b-d7339a6bc0e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MinneapolisRetailMeatCuttersAndFoodHandlersVariableAnnuityPensionFundMember_ed3436a1-bae1-4ba7-bb02-16f5ccaf2326" xlink:href="unfi-20250802.xsd#unfi_MinneapolisRetailMeatCuttersAndFoodHandlersVariableAnnuityPensionFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_c0db1424-438b-4b6f-946e-195ced9d3b6e" xlink:to="loc_unfi_MinneapolisRetailMeatCuttersAndFoodHandlersVariableAnnuityPensionFundMember_ed3436a1-bae1-4ba7-bb02-16f5ccaf2326" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_CentralStatesSoutheastandSouthwestAreasPensionFundMember_db6e5725-4981-478d-81cb-3bdce4a61468" xlink:href="unfi-20250802.xsd#unfi_CentralStatesSoutheastandSouthwestAreasPensionFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_c0db1424-438b-4b6f-946e-195ced9d3b6e" xlink:to="loc_unfi_CentralStatesSoutheastandSouthwestAreasPensionFundMember_db6e5725-4981-478d-81cb-3bdce4a61468" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_UFCWUnionsAndParticipatingEmployersPensionFundMember_1b160ad1-f7ba-40dc-9ba5-f5cbb35979cf" xlink:href="unfi-20250802.xsd#unfi_UFCWUnionsAndParticipatingEmployersPensionFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_c0db1424-438b-4b6f-946e-195ced9d3b6e" xlink:to="loc_unfi_UFCWUnionsAndParticipatingEmployersPensionFundMember_1b160ad1-f7ba-40dc-9ba5-f5cbb35979cf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_WesternConferenceOfTeamstersPensionPlanMember_ef6502b6-9675-4103-ac6a-a2c82a7b0fd1" xlink:href="unfi-20250802.xsd#unfi_WesternConferenceOfTeamstersPensionPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_c0db1424-438b-4b6f-946e-195ced9d3b6e" xlink:to="loc_unfi_WesternConferenceOfTeamstersPensionPlanMember_ef6502b6-9675-4103-ac6a-a2c82a7b0fd1" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_AllOtherMultiemployerPensionPlansMember_598909ee-24c7-4389-8984-915cb7c9a9d5" xlink:href="unfi-20250802.xsd#unfi_AllOtherMultiemployerPensionPlansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_c0db1424-438b-4b6f-946e-195ced9d3b6e" xlink:to="loc_unfi_AllOtherMultiemployerPensionPlansMember_598909ee-24c7-4389-8984-915cb7c9a9d5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlanPensionSignificantFundingImprovementOrRehabilitationPlanImplementationStatusFixedList_63abddd1-2be9-48ea-9e52-4f1fde06d622" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlanPensionSignificantFundingImprovementOrRehabilitationPlanImplementationStatusFixedList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8d5789bf-fc0d-4976-a750-cff552d8c3db" xlink:to="loc_us-gaap_MultiemployerPlanPensionSignificantFundingImprovementOrRehabilitationPlanImplementationStatusFixedList_63abddd1-2be9-48ea-9e52-4f1fde06d622" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlanEmployerContributionCost_c3cad160-2328-49e4-b268-82ecc8e9e3c7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlanEmployerContributionCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8d5789bf-fc0d-4976-a750-cff552d8c3db" xlink:to="loc_us-gaap_MultiemployerPlanEmployerContributionCost_c3cad160-2328-49e4-b268-82ecc8e9e3c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList_3bb40b6f-69ab-43dc-91d1-8b0f0699482d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8d5789bf-fc0d-4976-a750-cff552d8c3db" xlink:to="loc_us-gaap_MultiemployerPlanPensionSignificantSurchargeFixedList_3bb40b6f-69ab-43dc-91d1-8b0f0699482d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlanPPASurchargesonEligibleContributionsPercent_bc4dc4f9-757a-40d7-a077-69d65f787edf" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlanPPASurchargesonEligibleContributionsPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8d5789bf-fc0d-4976-a750-cff552d8c3db" xlink:to="loc_unfi_MultiemployerPlanPPASurchargesonEligibleContributionsPercent_bc4dc4f9-757a-40d7-a077-69d65f787edf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlanNumberofPlans_5389acb6-7f5d-479f-9aad-2aec0bb2f3a4" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlanNumberofPlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8d5789bf-fc0d-4976-a750-cff552d8c3db" xlink:to="loc_unfi_MultiemployerPlanNumberofPlans_5389acb6-7f5d-479f-9aad-2aec0bb2f3a4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlanPensionNumberOfPlansWithoutFutureContributions_afbfb907-39ce-4d15-b145-833a3fc12727" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlanPensionNumberOfPlansWithoutFutureContributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_8d5789bf-fc0d-4976-a750-cff552d8c3db" xlink:to="loc_unfi_MultiemployerPlanPensionNumberOfPlansWithoutFutureContributions_afbfb907-39ce-4d15-b145-833a3fc12727" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSScheduleofCollectiveBargainingAgreementDatesandContributionstoEachPlanTableDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSScheduleofCollectiveBargainingAgreementDatesandContributionstoEachPlanTableDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSScheduleofCollectiveBargainingAgreementDatesandContributionstoEachPlanTableDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_35e66181-44a5-406e-a1b3-f62b3f9647db" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_41cc747a-18eb-4cf8-8d8e-0b79a1f35a2e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_35e66181-44a5-406e-a1b3-f62b3f9647db" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_41cc747a-18eb-4cf8-8d8e-0b79a1f35a2e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameAxis_3ce5e50d-2389-4047-9f63-4865126d521f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_41cc747a-18eb-4cf8-8d8e-0b79a1f35a2e" xlink:to="loc_us-gaap_RetirementPlanNameAxis_3ce5e50d-2389-4047-9f63-4865126d521f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_3ce5e50d-2389-4047-9f63-4865126d521f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanNameAxis_3ce5e50d-2389-4047-9f63-4865126d521f" xlink:to="loc_us-gaap_RetirementPlanNameDomain_3ce5e50d-2389-4047-9f63-4865126d521f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanNameDomain_db11a5d8-4420-4529-af38-46b03f305fec" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanNameAxis_3ce5e50d-2389-4047-9f63-4865126d521f" xlink:to="loc_us-gaap_RetirementPlanNameDomain_db11a5d8-4420-4529-af38-46b03f305fec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MinneapolisFoodDistributingIndustryPensionPlanMember_617997ab-e2ef-4d74-8f5c-6ebf5b29ad50" xlink:href="unfi-20250802.xsd#unfi_MinneapolisFoodDistributingIndustryPensionPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_db11a5d8-4420-4529-af38-46b03f305fec" xlink:to="loc_unfi_MinneapolisFoodDistributingIndustryPensionPlanMember_617997ab-e2ef-4d74-8f5c-6ebf5b29ad50" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MinneapolisRetailMeatCuttersAndFoodHandlersPensionFundMember_82adf722-c7a7-404a-8fe3-f10ceae45a20" xlink:href="unfi-20250802.xsd#unfi_MinneapolisRetailMeatCuttersAndFoodHandlersPensionFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_db11a5d8-4420-4529-af38-46b03f305fec" xlink:to="loc_unfi_MinneapolisRetailMeatCuttersAndFoodHandlersPensionFundMember_82adf722-c7a7-404a-8fe3-f10ceae45a20" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MinneapolisRetailMeatCuttersAndFoodHandlersVariableAnnuityPensionFundMember_34f76ff9-d673-40df-bf49-9a570c576c55" xlink:href="unfi-20250802.xsd#unfi_MinneapolisRetailMeatCuttersAndFoodHandlersVariableAnnuityPensionFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_db11a5d8-4420-4529-af38-46b03f305fec" xlink:to="loc_unfi_MinneapolisRetailMeatCuttersAndFoodHandlersVariableAnnuityPensionFundMember_34f76ff9-d673-40df-bf49-9a570c576c55" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_CentralStatesSoutheastandSouthwestAreasPensionFundMember_640374ff-05bd-4aa3-89fd-b3dd8307bd17" xlink:href="unfi-20250802.xsd#unfi_CentralStatesSoutheastandSouthwestAreasPensionFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_db11a5d8-4420-4529-af38-46b03f305fec" xlink:to="loc_unfi_CentralStatesSoutheastandSouthwestAreasPensionFundMember_640374ff-05bd-4aa3-89fd-b3dd8307bd17" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_UfcwUnionsAndParticipatingEmployersPensionFundMember_35e1edd8-960d-42e5-a148-3a42148adaf7" xlink:href="unfi-20250802.xsd#unfi_UfcwUnionsAndParticipatingEmployersPensionFundMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_db11a5d8-4420-4529-af38-46b03f305fec" xlink:to="loc_unfi_UfcwUnionsAndParticipatingEmployersPensionFundMember_35e1edd8-960d-42e5-a148-3a42148adaf7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_WesternConferenceOfTeamstersPensionPlanMember_524eb547-5919-4745-9f40-d3fe0abe8c8d" xlink:href="unfi-20250802.xsd#unfi_WesternConferenceOfTeamstersPensionPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanNameDomain_db11a5d8-4420-4529-af38-46b03f305fec" xlink:to="loc_unfi_WesternConferenceOfTeamstersPensionPlanMember_524eb547-5919-4745-9f40-d3fe0abe8c8d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_NumberOfCollectiveBargainingAgreements_a417e595-8cbe-4667-85d5-4a8e08396d6d" xlink:href="unfi-20250802.xsd#unfi_NumberOfCollectiveBargainingAgreements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_35e66181-44a5-406e-a1b3-f62b3f9647db" xlink:to="loc_unfi_NumberOfCollectiveBargainingAgreements_a417e595-8cbe-4667-85d5-4a8e08396d6d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlanPensionSignificantEmployeesCoveredByCollectiveBargainingArrangementToAllEntitysEmployeesPercentage_2c8beebf-8ed6-491c-b6c9-bdec10250db7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlanPensionSignificantEmployeesCoveredByCollectiveBargainingArrangementToAllEntitysEmployeesPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_35e66181-44a5-406e-a1b3-f62b3f9647db" xlink:to="loc_us-gaap_MultiemployerPlanPensionSignificantEmployeesCoveredByCollectiveBargainingArrangementToAllEntitysEmployeesPercentage_2c8beebf-8ed6-491c-b6c9-bdec10250db7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlanPensionSignificantEmployerContributionExceedsFivePercent_e6aaf0af-1956-444c-a0f9-ae6bb36cbbc6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlanPensionSignificantEmployerContributionExceedsFivePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_35e66181-44a5-406e-a1b3-f62b3f9647db" xlink:to="loc_us-gaap_MultiemployerPlanPensionSignificantEmployerContributionExceedsFivePercent_e6aaf0af-1956-444c-a0f9-ae6bb36cbbc6" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BENEFITPLANSMultiemployerBenefitPlansOtherthanPensionsDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BENEFITPLANSMultiemployerBenefitPlansOtherthanPensionsDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BENEFITPLANSMultiemployerBenefitPlansOtherthanPensionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_5eea19cb-5b72-43ca-9b20-de5f98efa144" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_4bcf79d3-daa0-4e73-baf9-73f5d93ef3a0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_5eea19cb-5b72-43ca-9b20-de5f98efa144" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_4bcf79d3-daa0-4e73-baf9-73f5d93ef3a0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_1f57387a-e4c7-4428-acf0-30e2e4c0f39f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_4bcf79d3-daa0-4e73-baf9-73f5d93ef3a0" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_1f57387a-e4c7-4428-acf0-30e2e4c0f39f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_1f57387a-e4c7-4428-acf0-30e2e4c0f39f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_1f57387a-e4c7-4428-acf0-30e2e4c0f39f" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_1f57387a-e4c7-4428-acf0-30e2e4c0f39f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_b89950aa-7b2c-4fde-997d-4b602088dd29" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_1f57387a-e4c7-4428-acf0-30e2e4c0f39f" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_b89950aa-7b2c-4fde-997d-4b602088dd29" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_72a65ac7-abdb-46c5-994a-9842ea3fedba" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_b89950aa-7b2c-4fde-997d-4b602088dd29" xlink:to="loc_us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember_72a65ac7-abdb-46c5-994a-9842ea3fedba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MultiemployerPlanEmployerContributionCost_bebbdca3-6829-40de-919f-b70d4b14df3e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_MultiemployerPlanEmployerContributionCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_5eea19cb-5b72-43ca-9b20-de5f98efa144" xlink:to="loc_us-gaap_MultiemployerPlanEmployerContributionCost_bebbdca3-6829-40de-919f-b70d4b14df3e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/INCOMETAXESTaxCreditsandValuationAllowancesDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#INCOMETAXESTaxCreditsandValuationAllowancesDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/INCOMETAXESTaxCreditsandValuationAllowancesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TaxCreditCarryforwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TaxCreditCarryforwardTable_c1b1f22e-df67-4445-bc1c-e0d0f93e0ee1" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_TaxCreditCarryforwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:to="loc_us-gaap_TaxCreditCarryforwardTable_c1b1f22e-df67-4445-bc1c-e0d0f93e0ee1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_98902c37-8f4c-4c11-ad43-cf0542a661f4" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_TaxCreditCarryforwardTable_c1b1f22e-df67-4445-bc1c-e0d0f93e0ee1" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_98902c37-8f4c-4c11-ad43-cf0542a661f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_98902c37-8f4c-4c11-ad43-cf0542a661f4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_98902c37-8f4c-4c11-ad43-cf0542a661f4" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_98902c37-8f4c-4c11-ad43-cf0542a661f4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_a3daac49-69c8-4dcd-92af-7f57f528eaae" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_98902c37-8f4c-4c11-ad43-cf0542a661f4" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_a3daac49-69c8-4dcd-92af-7f57f528eaae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InternalRevenueServiceIRSMember_2b74b11d-25c0-42db-8f2b-cae3b4f5972e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InternalRevenueServiceIRSMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_a3daac49-69c8-4dcd-92af-7f57f528eaae" xlink:to="loc_us-gaap_InternalRevenueServiceIRSMember_2b74b11d-25c0-42db-8f2b-cae3b4f5972e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsGross_0981f8f6-e1c2-408e-b089-88598044d4db" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:to="loc_us-gaap_DeferredTaxAssetsGross_0981f8f6-e1c2-408e-b089-88598044d4db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_84ea58c8-63d4-45e0-b884-69a7b45913b9" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:to="loc_us-gaap_OperatingLossCarryforwards_84ea58c8-63d4-45e0-b884-69a7b45913b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_OperatingLossCarryforwardsLimitationsOnUseAmount_e855af75-e89b-4481-9a0d-d2b5a1f42190" xlink:href="unfi-20250802.xsd#unfi_OperatingLossCarryforwardsLimitationsOnUseAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:to="loc_unfi_OperatingLossCarryforwardsLimitationsOnUseAmount_e855af75-e89b-4481-9a0d-d2b5a1f42190" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DeferredTaxAssetsDisallowedInterestExpenseCarryforward_70a47e2c-e085-48e2-bb09-f6c0418e98fd" xlink:href="unfi-20250802.xsd#unfi_DeferredTaxAssetsDisallowedInterestExpenseCarryforward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:to="loc_unfi_DeferredTaxAssetsDisallowedInterestExpenseCarryforward_70a47e2c-e085-48e2-bb09-f6c0418e98fd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DeferredTaxAssetsDisallowedInterestExpenseCarryforwardUtilized_025c4802-1036-4f64-8918-b25539888506" xlink:href="unfi-20250802.xsd#unfi_DeferredTaxAssetsDisallowedInterestExpenseCarryforwardUtilized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:to="loc_unfi_DeferredTaxAssetsDisallowedInterestExpenseCarryforwardUtilized_025c4802-1036-4f64-8918-b25539888506" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_DeferredTaxAssetsDisallowedInterestExpenseCarryforwardValuationAllowance_64c4ab6b-0eef-4b3f-91c7-9a47926ea30f" xlink:href="unfi-20250802.xsd#unfi_DeferredTaxAssetsDisallowedInterestExpenseCarryforwardValuationAllowance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:to="loc_unfi_DeferredTaxAssetsDisallowedInterestExpenseCarryforwardValuationAllowance_64c4ab6b-0eef-4b3f-91c7-9a47926ea30f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsForeign_145256c3-0ab6-4f8c-8da9-063c3f683732" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsForeign"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:to="loc_us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsForeign_145256c3-0ab6-4f8c-8da9-063c3f683732" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_36c10b3d-e8b1-420e-85ef-9f74df882434" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxCreditCarryforwardLineItems_6b07e66d-939a-4b07-8ed1-4e463da68fd2" xlink:to="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_36c10b3d-e8b1-420e-85ef-9f74df882434" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/BUSINESSSEGMENTSSegmentInformationDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#BUSINESSSEGMENTSSegmentInformationDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/BUSINESSSEGMENTSSegmentInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b358cb67-9b1a-45ea-897e-a74c48a037be" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b358cb67-9b1a-45ea-897e-a74c48a037be" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_f2d05f74-1421-42af-804a-e46d02cd8d7e" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b358cb67-9b1a-45ea-897e-a74c48a037be" xlink:to="loc_srt_ConsolidationItemsAxis_f2d05f74-1421-42af-804a-e46d02cd8d7e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_f2d05f74-1421-42af-804a-e46d02cd8d7e_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_f2d05f74-1421-42af-804a-e46d02cd8d7e" xlink:to="loc_srt_ConsolidationItemsDomain_f2d05f74-1421-42af-804a-e46d02cd8d7e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_33093c92-a4be-4c02-b184-e2f60e33a217" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_f2d05f74-1421-42af-804a-e46d02cd8d7e" xlink:to="loc_srt_ConsolidationItemsDomain_33093c92-a4be-4c02-b184-e2f60e33a217" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_3ebe9a6d-2030-4267-9c33-a861e3d589ea" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_33093c92-a4be-4c02-b184-e2f60e33a217" xlink:to="loc_us-gaap_OperatingSegmentsMember_3ebe9a6d-2030-4267-9c33-a861e3d589ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_228d4229-eb25-4808-9337-6367bf784926" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_33093c92-a4be-4c02-b184-e2f60e33a217" xlink:to="loc_us-gaap_CorporateNonSegmentMember_228d4229-eb25-4808-9337-6367bf784926" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IntersegmentEliminationMember_989a3d41-8c68-4f37-8a33-9468f72e299f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IntersegmentEliminationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_33093c92-a4be-4c02-b184-e2f60e33a217" xlink:to="loc_us-gaap_IntersegmentEliminationMember_989a3d41-8c68-4f37-8a33-9468f72e299f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_59eff7e6-0e9d-47eb-aff7-1385aad1a395" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_b358cb67-9b1a-45ea-897e-a74c48a037be" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_59eff7e6-0e9d-47eb-aff7-1385aad1a395" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_59eff7e6-0e9d-47eb-aff7-1385aad1a395_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_59eff7e6-0e9d-47eb-aff7-1385aad1a395" xlink:to="loc_us-gaap_SegmentDomain_59eff7e6-0e9d-47eb-aff7-1385aad1a395_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_7d7220e8-5c86-440f-9435-28136560d17e" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_59eff7e6-0e9d-47eb-aff7-1385aad1a395" xlink:to="loc_us-gaap_SegmentDomain_7d7220e8-5c86-440f-9435-28136560d17e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_NaturalSegmentMember_3127f48f-9c70-46a4-a704-7e01b8b9a8e2" xlink:href="unfi-20250802.xsd#unfi_NaturalSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_7d7220e8-5c86-440f-9435-28136560d17e" xlink:to="loc_unfi_NaturalSegmentMember_3127f48f-9c70-46a4-a704-7e01b8b9a8e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ConventionalSegmentMember_1f5c886b-84b1-4602-a406-bc9d5a8424ee" xlink:href="unfi-20250802.xsd#unfi_ConventionalSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_7d7220e8-5c86-440f-9435-28136560d17e" xlink:to="loc_unfi_ConventionalSegmentMember_1f5c886b-84b1-4602-a406-bc9d5a8424ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_RetailSegmentMember_d994aaee-d909-4a90-8715-9a279fe2e9c3" xlink:href="unfi-20250802.xsd#unfi_RetailSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_7d7220e8-5c86-440f-9435-28136560d17e" xlink:to="loc_unfi_RetailSegmentMember_d994aaee-d909-4a90-8715-9a279fe2e9c3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_2e7f7113-aaff-45a9-8008-acc57628ab55" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_2e7f7113-aaff-45a9-8008-acc57628ab55" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_336357ed-6285-431d-97df-8555adef6de0" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_336357ed-6285-431d-97df-8555adef6de0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductionAndDistributionCosts_b983533c-e8c4-4ae7-971a-cd2bb3315957" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_ProductionAndDistributionCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_ProductionAndDistributionCosts_b983533c-e8c4-4ae7-971a-cd2bb3315957" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingOtherItemAmount_e3313a78-fe0b-4669-8bce-3d96fc26f285" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentReportingOtherItemAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_SegmentReportingOtherItemAmount_e3313a78-fe0b-4669-8bce-3d96fc26f285" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_AdjustedEBITDA_8dae5fd0-5599-487f-93a0-a7ec9da8feaa" xlink:href="unfi-20250802.xsd#unfi_AdjustedEBITDA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_unfi_AdjustedEBITDA_8dae5fd0-5599-487f-93a0-a7ec9da8feaa" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_NetIncomeAttributableToNoncontrollingInterests_d44d8c89-9348-407c-a519-2472ec4aded4" xlink:href="unfi-20250802.xsd#unfi_NetIncomeAttributableToNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_unfi_NetIncomeAttributableToNoncontrollingInterests_d44d8c89-9348-407c-a519-2472ec4aded4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent_a9aeed6e-5c11-4435-b91c-35bdb2d04977" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_NetPeriodicDefinedBenefitsExpenseReversalOfExpenseExcludingServiceCostComponent_a9aeed6e-5c11-4435-b91c-35bdb2d04977" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_ee0f6370-5a0d-4b68-8347-73adf51a7889" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_InterestExpenseNonoperating_ee0f6370-5a0d-4b68-8347-73adf51a7889" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_ac153d58-621e-4fea-afee-d743b0d7709c" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_ac153d58-621e-4fea-afee-d743b0d7709c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_362f623e-afa5-4907-a8cd-2244da2868b3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_Depreciation_362f623e-afa5-4907-a8cd-2244da2868b3" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ShareBasedCompensationEBITDAAdjustment_7b530923-c9c3-4757-932b-0556faeadc84" xlink:href="unfi-20250802.xsd#unfi_ShareBasedCompensationEBITDAAdjustment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_unfi_ShareBasedCompensationEBITDAAdjustment_7b530923-c9c3-4757-932b-0556faeadc84" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InventoryLIFOReservePeriodCharge_574b9969-1bb3-4a40-b4c5-0b6e201ab4a5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_InventoryLIFOReservePeriodCharge"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_InventoryLIFOReservePeriodCharge_574b9969-1bb3-4a40-b4c5-0b6e201ab4a5" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringSettlementAndImpairmentProvisions_8af5b2f1-8ddd-46fb-9caf-c9a0438258cd" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_RestructuringSettlementAndImpairmentProvisions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_RestructuringSettlementAndImpairmentProvisions_8af5b2f1-8ddd-46fb-9caf-c9a0438258cd" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnDispositionOfAssets1_577c3185-d821-4633-a450-8841bb931a44" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GainLossOnDispositionOfAssets1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_GainLossOnDispositionOfAssets1_577c3185-d821-4633-a450-8841bb931a44" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_MultiemployerPlanWithdrawalCharges_950cfc02-ce77-42bc-9454-a758cd242198" xlink:href="unfi-20250802.xsd#unfi_MultiemployerPlanWithdrawalCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_unfi_MultiemployerPlanWithdrawalCharges_950cfc02-ce77-42bc-9454-a758cd242198" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_OtherRetailExpense_ce82d8c0-3f40-4508-96cb-63c83024e7c1" xlink:href="unfi-20250802.xsd#unfi_OtherRetailExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_unfi_OtherRetailExpense_ce82d8c0-3f40-4508-96cb-63c83024e7c1" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_GainLossOnBusinessTransformation_335090e7-2d98-4f8d-bf5c-fbc1f7228904" xlink:href="unfi-20250802.xsd#unfi_GainLossOnBusinessTransformation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_unfi_GainLossOnBusinessTransformation_335090e7-2d98-4f8d-bf5c-fbc1f7228904" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonrecurringExpense_4c895804-0a7a-4cae-bc0e-5ced95796ce7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherNonrecurringExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_OtherNonrecurringExpense_4c895804-0a7a-4cae-bc0e-5ced95796ce7" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIncome_5d128797-abbd-4e89-b1e6-168e5b48d62a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_OtherIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_OtherIncome_5d128797-abbd-4e89-b1e6-168e5b48d62a" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_70a8010d-e9f8-4a92-8f9e-7c83aa2ddbd7" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_70a8010d-e9f8-4a92-8f9e-7c83aa2ddbd7" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_208627c9-ed82-4c78-8dbe-fd0b369d86b8" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_208627c9-ed82-4c78-8dbe-fd0b369d86b8" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_96ee9ab2-a19a-46b7-ab4a-c1f1a6fa8daf" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_SegmentExpenditureAdditionToLongLivedAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_e99c5616-fc24-4ab3-9f49-645e79310e1d" xlink:to="loc_us-gaap_SegmentExpenditureAdditionToLongLivedAssets_96ee9ab2-a19a-46b7-ab4a-c1f1a6fa8daf" xlink:type="arc" order="21"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.unfi.com/role/COMMITMENTSCONTINGENCIESANDOFFBALANCESHEETARRANGEMENTSDetails" xlink:type="simple" xlink:href="unfi-20250802.xsd#COMMITMENTSCONTINGENCIESANDOFFBALANCESHEETARRANGEMENTSDetails"/>
  <link:definitionLink xlink:role="http://www.unfi.com/role/COMMITMENTSCONTINGENCIESANDOFFBALANCESHEETARRANGEMENTSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingenciesTable_eee170c3-f8e9-436a-a1ba-9cd077d12203" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingenciesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:to="loc_us-gaap_LossContingenciesTable_eee170c3-f8e9-436a-a1ba-9cd077d12203" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e076a830-998d-4652-b815-8284b69e1255" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_eee170c3-f8e9-436a-a1ba-9cd077d12203" xlink:to="loc_srt_RangeAxis_e076a830-998d-4652-b815-8284b69e1255" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e076a830-998d-4652-b815-8284b69e1255_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_e076a830-998d-4652-b815-8284b69e1255" xlink:to="loc_srt_RangeMember_e076a830-998d-4652-b815-8284b69e1255_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8bdb4dac-a0bf-49dd-8bcb-4d1b56822d66" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_e076a830-998d-4652-b815-8284b69e1255" xlink:to="loc_srt_RangeMember_8bdb4dac-a0bf-49dd-8bcb-4d1b56822d66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_00199e89-44a8-413f-aa55-a8bc1af2e953" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8bdb4dac-a0bf-49dd-8bcb-4d1b56822d66" xlink:to="loc_srt_MinimumMember_00199e89-44a8-413f-aa55-a8bc1af2e953" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_3539b495-286f-4243-b456-75b1c42ca049" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8bdb4dac-a0bf-49dd-8bcb-4d1b56822d66" xlink:to="loc_srt_MaximumMember_3539b495-286f-4243-b456-75b1c42ca049" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember_b0e09eba-e00a-43af-af86-2d52b837d927" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_WeightedAverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8bdb4dac-a0bf-49dd-8bcb-4d1b56822d66" xlink:to="loc_srt_WeightedAverageMember_b0e09eba-e00a-43af-af86-2d52b837d927" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsByNatureAxis_b1631c03-cb29-4217-a273-244669ad85f6" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsByNatureAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_eee170c3-f8e9-436a-a1ba-9cd077d12203" xlink:to="loc_us-gaap_GuaranteeObligationsByNatureAxis_b1631c03-cb29-4217-a273-244669ad85f6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_b1631c03-cb29-4217-a273-244669ad85f6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_b1631c03-cb29-4217-a273-244669ad85f6" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_b1631c03-cb29-4217-a273-244669ad85f6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsNatureDomain_19f06a2d-3c69-4522-9bbd-157d77f07378" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsNatureDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GuaranteeObligationsByNatureAxis_b1631c03-cb29-4217-a273-244669ad85f6" xlink:to="loc_us-gaap_GuaranteeObligationsNatureDomain_19f06a2d-3c69-4522-9bbd-157d77f07378" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentGuaranteeMember_fa052b52-2779-40c0-8a06-50561d3eea51" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PaymentGuaranteeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GuaranteeObligationsNatureDomain_19f06a2d-3c69-4522-9bbd-157d77f07378" xlink:to="loc_us-gaap_PaymentGuaranteeMember_fa052b52-2779-40c0-8a06-50561d3eea51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_63da54d9-b8fe-4c12-8bed-d00fac115a02" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_eee170c3-f8e9-436a-a1ba-9cd077d12203" xlink:to="loc_srt_LitigationCaseAxis_63da54d9-b8fe-4c12-8bed-d00fac115a02" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_63da54d9-b8fe-4c12-8bed-d00fac115a02_default" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_63da54d9-b8fe-4c12-8bed-d00fac115a02" xlink:to="loc_srt_LitigationCaseTypeDomain_63da54d9-b8fe-4c12-8bed-d00fac115a02_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_3199e91f-fd89-4f1a-9746-14834c53a1b6" xlink:href="https://xbrl.fasb.org/srt/2025/elts/srt-2025.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_63da54d9-b8fe-4c12-8bed-d00fac115a02" xlink:to="loc_srt_LitigationCaseTypeDomain_3199e91f-fd89-4f1a-9746-14834c53a1b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_NationalOpioidEpidemicMember_4ed2c2c1-5d93-4232-8e2f-14f5cf87dca1" xlink:href="unfi-20250802.xsd#unfi_NationalOpioidEpidemicMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_3199e91f-fd89-4f1a-9746-14834c53a1b6" xlink:to="loc_unfi_NationalOpioidEpidemicMember_4ed2c2c1-5d93-4232-8e2f-14f5cf87dca1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_ComplaintFromVariousHealthPlansMember_c19499d8-4893-4fe7-8b6b-9945cfaac8ca" xlink:href="unfi-20250802.xsd#unfi_ComplaintFromVariousHealthPlansMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_3199e91f-fd89-4f1a-9746-14834c53a1b6" xlink:to="loc_unfi_ComplaintFromVariousHealthPlansMember_c19499d8-4893-4fe7-8b6b-9945cfaac8ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_SchutteandYarberryv.SuperValuNewAlbertsonsInc.etalMember_97612fd5-4a67-4f99-8b5a-c51ab8849677" xlink:href="unfi-20250802.xsd#unfi_SchutteandYarberryv.SuperValuNewAlbertsonsInc.etalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_3199e91f-fd89-4f1a-9746-14834c53a1b6" xlink:to="loc_unfi_SchutteandYarberryv.SuperValuNewAlbertsonsInc.etalMember_97612fd5-4a67-4f99-8b5a-c51ab8849677" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LegalEntityAxis_f8dfca1f-1d1b-42cd-aa56-69ce7afd2083" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_LegalEntityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LossContingenciesTable_eee170c3-f8e9-436a-a1ba-9cd077d12203" xlink:to="loc_dei_LegalEntityAxis_f8dfca1f-1d1b-42cd-aa56-69ce7afd2083" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_f8dfca1f-1d1b-42cd-aa56-69ce7afd2083_default" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_dei_LegalEntityAxis_f8dfca1f-1d1b-42cd-aa56-69ce7afd2083" xlink:to="loc_dei_EntityDomain_f8dfca1f-1d1b-42cd-aa56-69ce7afd2083_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityDomain_b8e889a9-7400-46d8-8658-d256686220d4" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_dei_LegalEntityAxis_f8dfca1f-1d1b-42cd-aa56-69ce7afd2083" xlink:to="loc_dei_EntityDomain_b8e889a9-7400-46d8-8658-d256686220d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_AdvantageLogisticsMember_b8b93f0b-8788-490c-8f20-13cd1dacb9a3" xlink:href="unfi-20250802.xsd#unfi_AdvantageLogisticsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_dei_EntityDomain_b8e889a9-7400-46d8-8658-d256686220d4" xlink:to="loc_unfi_AdvantageLogisticsMember_b8b93f0b-8788-490c-8f20-13cd1dacb9a3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_GuarantorObligationsGuaranteesTerm_10736d97-c055-4594-9b8f-485d10f056fc" xlink:href="unfi-20250802.xsd#unfi_GuarantorObligationsGuaranteesTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:to="loc_unfi_GuarantorObligationsGuaranteesTerm_10736d97-c055-4594-9b8f-485d10f056fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GuaranteeObligationsMaximumExposure_cfe1acd3-9a92-4d89-a09e-d259ec2e83c5" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_GuaranteeObligationsMaximumExposure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:to="loc_us-gaap_GuaranteeObligationsMaximumExposure_cfe1acd3-9a92-4d89-a09e-d259ec2e83c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_GuarantorObligationsMaximumExposureDiscounted_1b993b54-9d2b-4e74-8548-b0f55ff7c2c6" xlink:href="unfi-20250802.xsd#unfi_GuarantorObligationsMaximumExposureDiscounted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:to="loc_unfi_GuarantorObligationsMaximumExposureDiscounted_1b993b54-9d2b-4e74-8548-b0f55ff7c2c6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PurchaseObligation_9d74abd5-d61a-4831-9915-080aa9c3af6a" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PurchaseObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:to="loc_us-gaap_PurchaseObligation_9d74abd5-d61a-4831-9915-080aa9c3af6a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyPendingClaimsNumber_93672432-4290-4f62-9cbb-2b06ab65b923" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyPendingClaimsNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:to="loc_us-gaap_LossContingencyPendingClaimsNumber_93672432-4290-4f62-9cbb-2b06ab65b923" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyNewClaimsFiledNumber_4ad04ca3-5128-4561-b26a-9713d375d5df" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyNewClaimsFiledNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:to="loc_us-gaap_LossContingencyNewClaimsFiledNumber_4ad04ca3-5128-4561-b26a-9713d375d5df" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyDamagesSoughtValue_97a36a6d-b1e7-4990-ac55-2f91111ad83f" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LossContingencyDamagesSoughtValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:to="loc_us-gaap_LossContingencyDamagesSoughtValue_97a36a6d-b1e7-4990-ac55-2f91111ad83f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_LossContingencyShareofPotentialAwardValue_c90834be-15db-46b6-85f8-930bd900b120" xlink:href="unfi-20250802.xsd#unfi_LossContingencyShareofPotentialAwardValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LossContingenciesLineItems_dea1df54-bdbf-405a-802d-cd8f29544be3" xlink:to="loc_unfi_LossContingencyShareofPotentialAwardValue_c90834be-15db-46b6-85f8-930bd900b120" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-roles-2025.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_unfi_GainLossOnDispositionOfPropertyPlantEquipmentNet_7272cadd-2a27-486e-9549-d486467cfd5f" xlink:href="unfi-20250802.xsd#unfi_GainLossOnDispositionOfPropertyPlantEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract" xlink:to="loc_unfi_GainLossOnDispositionOfPropertyPlantEquipmentNet_7272cadd-2a27-486e-9549-d486467cfd5f" xlink:type="arc" order="691"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:type="arc" order="41"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="loc_us-gaap_LongTermDebtAndCapitalLeaseObligationsCurrent" xlink:type="arc" order="42"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:href="https://xbrl.fasb.org/us-gaap/2025/elts/us-gaap-2025.xsd#us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentAndFinanceLeaseRightOfUseAssetAfterAccumulatedDepreciationAndAmortization" xlink:type="arc" order="101"/>
  </link:definitionLink>
</link:linkbase>
