<SEC-DOCUMENT>0001562180-21-004412.txt : 20210621
<SEC-HEADER>0001562180-21-004412.hdr.sgml : 20210621
<ACCEPTANCE-DATETIME>20210621201855
ACCESSION NUMBER:		0001562180-21-004412
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210617
FILED AS OF DATE:		20210621
DATE AS OF CHANGE:		20210621

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Chard Daniel R
		CENTRAL INDEX KEY:			0001289557

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31573
		FILM NUMBER:		211032685

	MAIL ADDRESS:	
		STREET 1:		NU SKIN ENTERPRISES, INC.
		STREET 2:		75 WEST CENTER STREET
		CITY:			PROVO
		STATE:			UT
		ZIP:			84601

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MEDIFAST INC
		CENTRAL INDEX KEY:			0000910329
		STANDARD INDUSTRIAL CLASSIFICATION:	MISCELLANEOUS FOOD PREPARATIONS & KINDRED PRODUCTS [2090]
		IRS NUMBER:				133714405
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		11445 CRONHILL DRIVE
		CITY:			OWINGS MILLS
		STATE:			MD
		ZIP:			21117
		BUSINESS PHONE:		7327640619

	MAIL ADDRESS:	
		STREET 1:		11445 CRONHILL DRIVE
		CITY:			OWINGS MILLS
		STATE:			MD
		ZIP:			21117

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	HEALTHRITE INC
		DATE OF NAME CHANGE:	19951120

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	XX
		DATE OF NAME CHANGE:	19950619

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	00
		DATE OF NAME CHANGE:	19950619
</SEC-HEADER>
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<TYPE>4
<SEQUENCE>1
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<DESCRIPTION>PRIMARY DOCUMENT
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    <schemaVersion>X0306</schemaVersion>

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    <periodOfReport>2021-06-17</periodOfReport>

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        <issuerCik>0000910329</issuerCik>
        <issuerName>MEDIFAST INC</issuerName>
        <issuerTradingSymbol>MED</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001289557</rptOwnerCik>
            <rptOwnerName>Chard Daniel R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MEDIFAST, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>100 INTERNATIONAL DRIVE, 18TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>BALTIMORE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21202</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>Chairman &amp; CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

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                <transactionPricePerShare>
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                <equitySwapInvolved>false</equitySwapInvolved>
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            <transactionAmounts>
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                    <footnoteId id="F1"/>
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                <transactionPricePerShare>
                    <value>263.3124</value>
                    <footnoteId id="F6"/>
                </transactionPricePerShare>
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                <sharesOwnedFollowingTransaction>
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                <transactionShares>
                    <value>213.00</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>264.3453</value>
                    <footnoteId id="F7"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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                <transactionPricePerShare>
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                    <footnoteId id="F1"/>
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                <transactionPricePerShare>
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                    <footnoteId id="F11"/>
                </transactionPricePerShare>
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            </transactionDate>
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                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
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                <transactionShares>
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                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>270.095</value>
                    <footnoteId id="F12"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
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                </transactionAcquiredDisposedCode>
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                <directOrIndirectOwnership>
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    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The shares are sold pursuant to a 10b5-1 Plan entered into by the Reporting Person on March 2, 2021</footnote>
        <footnote id="F10">This transaction was executed in multiple trades at prices ranging from $267.73 USD to $268.71 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F11">This transaction was executed in multiple trades at prices ranging from $268.87 USD to $269.61 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F12">This transaction was executed in multiple trades at prices ranging from $270.09 USD to $270.10 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F2">This transaction was executed in multiple trades at prices ranging from $258.74 USD to $259.66 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F3">This transaction was executed in multiple trades at prices ranging from $259.83 USD to $260.82 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F4">This transaction was executed in multiple trades at prices ranging from $260.94 USD to $261.92 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F5">This transaction was executed in multiple trades at prices ranging from $262.00 USD to $262.96 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F6">This transaction was executed in multiple trades at prices ranging from $263.00 USD to $263.48 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F7">This transaction was executed in multiple trades at prices ranging from $264.10 USD to $265.07 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F8">This transaction was executed in multiple trades at prices ranging from $265.10 USD to $265.79 USD; the price reported above reflects the weighted average sale price.</footnote>
        <footnote id="F9">This transaction was executed in multiple trades at prices ranging from $266.66 USD to $267.54 USD; the price reported above reflects the weighted average sale price.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Jason L. Groves, attorney-in-fact</signatureName>
        <signatureDate>2021-06-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
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</SEC-DOCUMENT>
