Exhibit 31.1

                                CEO Certification

I, Bradley T. MacDonald, the registrant, Chairman of the Board and Chief
Executive Officer certify that:

      1.    I have reviewed this quarterly report on Form 10-Q of Medifast,
            Inc.;

      2.    Based on my knowledge, this 10-Q does not contain any untrue
            statement of a material fact or omit to state a material fact
            necessary to make the statements made, in light of the circumstances
            under which such statements were made, not misleading with respect
            to the period covered by this report;

      3.    Based on my knowledge, the financial statements, and other financial
            information included in this report, fairly present in all material
            respects the financial condition, results of operations and cash
            flows of the registrant as of, and for the periods presented in this
            report;

      4.    I am responsible for establishing and maintaining disclosure
            controls and procedures (as defined in Exchange Act Rules 13a-14 and
            15d-14) for the registrant and have:

            a.    Designed such disclosure controls and procedures to ensure
                  that material information relating to the registrant,
                  including its consolidated subsidiaries, is made known to us
                  by others within those entities, particularly during the
                  period by which this report is being prepared;

            b.    Evaluated the effectiveness of the registrant's disclosure
                  controls and procedures and presented in this report our
                  conclusions about the effectiveness of the disclosure controls
                  and procedures, as of the end of the period covered by this
                  report based on such evaluation; and

            c.    Disclosed in this report any change in the registrant's
                  internal control over financial reporting that occurred during
                  the registrant's most recent fiscal quarter (the registrant's
                  fourth quarter in the case of an annual report) that has
                  materially affected, or is reasonably likely to materially
                  affect, the registrant's internal control over financial
                  reporting; and

      5.    I have disclosed, based on our most recent evaluation, to the
            registrant's auditors and the audit committee of registrant's board
            of directors:

            a.    All significant deficiencies in the design or operation of
                  internal controls which could adversely affect the
                  registrant's ability to record, process, summarize and report
                  financial data and have identified for the registrant's
                  auditors any material weaknesses in internal controls; and

            b.    Any fraud, whether or not material, that involves management
                  or other employees who have a significant role in the
                  registrant's internal control over financial reporting.

November 9, 2005


/s/ Bradley T. MacDonald

Bradley T. MacDonald
Chairman of the Board & Chief Executive Officer


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