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Comparison of Medifast's 5 & 1 Plan to a Food-based Plan of Equal Calories

This study has been completed.
Information provided by:
Medifast, Inc. Identifier:
First received: November 10, 2009
Last updated: NA
Last verified: November 2009
History: No changes posted
Portion-controlled meal replacements have been shown to be an effective weight control strategy in overweight and obese individuals. Thus, the investigators plan to evaluate the effect of Medifast's 5 & 1 program compared to an food-based diet plan of equal calories on the following indices: weight loss and maintenance of weight loss, satiety during weight loss, changes in biochemical markers of inflammation and oxidative stress following weight loss, and compliance and retention rates.

Condition Intervention
Other: Medifast 5 & 1 Plan for weight loss and weight maintenance
Other: Food-based diet plan for weight loss and weight maintenance

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: Efficacy of Medifast's 5 & 1 Program Compared to a Food-based Diet After a Period of Weight Loss and Weight Maintenance

Resource links provided by NLM:

Further study details as provided by Medifast, Inc.:

Primary Outcome Measures:
  • Weight change (in kilograms) from week 0 [ Time Frame: 16 weeks ]

Secondary Outcome Measures:
  • Satiety using a visual analog scale [ Time Frame: 16 weeks ]
  • Change in Inflammation represented by C-reactive protein [ Time Frame: 16 and 40 weeks ]
  • Change in Oxidative Stress represented by urine lipid peroxides [ Time Frame: 16 and 40 weeks ]
  • Blood Pressure change [ Time Frame: 16 and 40 weeks ]
  • Change in Pulse [ Time Frame: 16 and 40 weeks ]
  • Maintenance of weight lost during the 16 week weight loss phase expressed as weight regained from week 16 to week 40 (in kilograms) [ Time Frame: 24 weeks ]
  • Change in percent body fat (a measure representing a change in body composition) [ Time Frame: 16 and 40 weeks ]
  • Change in Blood lipids [ Time Frame: 16 and 40 weeks ]
  • Change in lean muscle mass (a measure representing change in body composition) [ Time Frame: 16 and 40 weeks ]
  • Change in Waist circumference (a measure representing change in body composition) [ Time Frame: 16 and 40 weeks ]
  • Change in Visceral Fat Rating (a measure representing change in body composition) [ Time Frame: 16 and 40 weeks ]

Enrollment: 90
Study Start Date: March 2008
Study Completion Date: September 2009
Primary Completion Date: September 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Medifast 5 & 1 Plan
Medifast's 5 & 1 Plan is a meal replacement plan for weight loss and weight maintenance.
Other: Medifast 5 & 1 Plan for weight loss and weight maintenance
Medifast's 5 & 1 Plan is a meal replacement program for weight loss that uses 5 Medifast meals and 1 self-prepared meal. The weight maintenance plan incorporates 3-5 Medifast meals as well as a certain amount of food from all other food groups.
Active Comparator: Food-based
The food-based arm followed a meal plan of self-selected foods that provided the same number of calories as the Medifast 5 & 1 plan.
Other: Food-based diet plan for weight loss and weight maintenance
The food-based group was provided a meal plan for weight loss based on the guidelines of the USDA Food Guide Pyramid providing the same number of calories as the Medifast 5 & 1 Plan. Weight maintenance calories were calculated and participants were provided meal plans from the USDA Food Guide Pyramid.


Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Adult males and females (age between 18 and 65)
  • Obese (BMI >=30.0 kg/m2 and <50.0 kg/m2)
  • Non-smokers
  • No known food allergies to wheat, gluten, soy or nuts
  • <14 alcoholic beverages per week
  • Willing and able to give informed consent
  • Not currently using appetite-affecting medications (e.g SSRIs, steroids, Ritalin)
  • Not pregnant or lactating
  • Primary care physician's permission for weight loss, normal labs and electrocardiogram (EKG) within past 1 year

Exclusion Criteria:

  • Actively dieting
  • Eating Attitudes Test (EAT) > 30
  • Chronic uncontrolled health problems (not including obesity or diabetes)
  • Pacemaker or other internal electronic medical device
  • Schizophrenia, history of bipolar disorder, current Major Depressive Disorder
  • Dependence on alcohol or sedative-hypnotic drugs (e.g. benzodiazepines)
  • Cognitive impairment severe enough to preclude informed consent
  • Taking weight loss or appetite-suppressant medications
  • Taking appetite affecting medications (e.g. SSRIs, steroids, Ritalin)
  • Food allergies to wheat, gluten, soy, or nuts
  • Pregnant or lactating
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Please refer to this study by its identifier: NCT01011491

United States, Maryland
Medifast, Inc.
Owings Mills, Maryland, United States, 21117
Sponsors and Collaborators
Medifast, Inc.
Principal Investigator: Lisa M Davis, PhD, PA-C Medifast, Inc.
  More Information


Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Lisa M. Davis, PhD, PA-C, CNS, LDN/ Vice President, Research & Development, Medifast, Inc. Identifier: NCT01011491     History of Changes
Other Study ID Numbers: MED014
20080292 ( Other Identifier: Western Institutional Review Board )
Study First Received: November 10, 2009
Last Updated: November 10, 2009

Keywords provided by Medifast, Inc.:
Weight loss
meal replacements
oxidative stress
visceral fat processed this record on May 25, 2017