Medifast uses both clinical research studies and retrospective analysis data from its Medifast clinics as the basis of its claim, "clinically proven." An overview of Medifast clinical research is provided below.

STUDY 1

• REFERENCE: Crowell, M.D. & Cheskin L.J. The Johns Hopkins University School of Medicine. Multicenter Evaluation of Health Benefits and Weight Loss on the Medifast Weight Management Program.
  
  
• PURPOSE: To retrospectively evaluate the efficacy of a medically supervised, protein-supplemented modified fasting program (Medifast) for weight reduction and to evaluate the impact of weight reduction on coexisting health problems.
  
  
• RESULTS: Medically supervised, protein-sparing modified fasts offer a safe and effective means of weight reduction and are accompanied by significant improvements in coexisting health problems. Of samples taken, males lost an average of 67 lbs and females lost an average of 47 lbs during fasting. The study found significant reductions in systolic and diastolic blood pressure, and total cholesterol and triglycerides, as well as the normalizing of blood pressure and hypertensive patients.

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STUDY 2

• REFERENCE: Cheskin, MD, FACP; Mitchell, MS; Lewis, BA; Jhaveri, MD Yep, BS. Johns Hopkins University School of Bloomberg Public Health. "Efficacy of 2 Diet Plans Designed for People with Type 2 Diabetes on Weight and Health Measures." The Diabetes Educator. 2008 January/February
  
  
• PURPOSE: To evaluate the efficacy of the standard ADA (American Diabeties Association) self-selected diet (SD) vs. a portion-controlled diabetic food diet (PCD) in obese patients with NIDDM. The study also evaluated not only the metabolic effects in the long term, but also compliance and any consequent medication changes in patients of the two weight loss regimens (16-34 weeks of active weight loss, 52 weeks of maintenance). The meal replacements (Medifast) used in this study are soy-based products (bars, shakes, soups) that are considerably lower in sugar than their non-diabetic counterparts and other popular diet products on the market.
  
  
• RESULTS:Significantly greater results were achieved after the initial 34 weeks of weight loss by participants in the PCD group in pounds and percent weight loss, insulin level and hemoglobin A1c. The PCD group also saw significant improvements within group in BMI, systolic BP, diastolic BP, waist/hip measurements, cholesterol, HDL triglycerides, glucose and percent body fat. Dropout rates were less in the PCD in both weight loss and weight maintenance. During weight loss, participants in the PCD group significantly decreased their use of medications to treat Type 2 DM. Participants in the PCD group also self-reported higher ease of compliance with the diet compared to the SD group (64.2% vs. 56.0%).

Researchers recommended that a PCD be considered for type 2 diabetics desiring weight loss, but that periodic use of SD during weight maintenance will not adversely affect weight loss efforts. The research supports that using a portion-controlled diet will produce comparable if not better outcomes in type 2 diabetics attempting to control their weight.

The study was published in the 2008 January/February issue of The Diabetes Educator. The peer-reviewed journal is the official journal of the American Association of Diabetes Educators. The study was also presented at American Diabetes Association's 65th Annual Scientific Session in San Diego, CA, June 11, 2005.

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STUDY 3

• REFERENCE: Cheskin, Lawrence J.; Davis, Lisa M.; Hanlon-Mitola, Andrea; Mitchell, Amy; Jhaveri,Ami; Mary, Yep; Mitchell, Vanessa. Johns Hopkins Bloomberg School of Public Health, Center for Human Nutrition, Department of International Health, Baltimore, MD 21205. "Efficacy of Parent-Child Dieting Plans Incorporating Medifast Meal Replacements for Weight Loss. RCT Comparing Balanced Energy Deficit Diets With or Without Meal Replacements for Weight Loss and Maintenance Among Children Dieting Alone or With a Parent."
  
  
• PURPOSE: To compare the safety and efficacy of supplemental Medifast portion-controlled meal replacements (MRs) with a USDA Food Guide Pyramid-based diet. Both weight loss diets were 20% energy-restricted (~500 kcal deficit). Eighty, 8-15 yo children, BMI>95th%ile, were screened and 40 randomized to either a MR diet (3 MRs/d during active weight loss and 2 MRs/d during maintenance) or to the food-based diet. Subjects were further randomized to dieting alone or with a parent.
  
  
• RESULTS: By ITT analysis, dieting with a parent vs. without or food vs MR, made no difference in weight outcome. However, following initial weight loss (6 mos) and 1 yr maintenance (18 mos), significant (p less than or equal to 0.05) benefits were seen in the MR group in BMI%ile (0 mos=98.8 ± 1.0, 6 mos=96.6 ± 3.2, 18 mos=96.4 ± 3.4); body fat (↓5.9%@ 6 mos, 5.3% @ 18 mos), total cholesterol (↓6.7%, 5.6%), LDL (↓19.8%, 7.9%) and triglycerides (↓23.6%, 22.3%). No significant between-group differences, differences in growth rates, or adverse events were observed. Conclusions: Among overweight 8-15 yo children, dieting with or without a parent, meal replacements were as safe and effective as a food-based diet for weight loss and maintenance. (Supported by Medifast Inc., MD)

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STUDY 4

• REFERENCE: Haddock, C.K.; Poston, W.S.C.; Foreyt, J.P.; DiBartolomeo, J.J.; and Warner, P.O. "Effectiveness of Medifast Supplements Combined with Obesity Pharmacotherapy: A Clinical Program Evaluation."
  
  
• PURPOSE: The purpose of the study is to evaluate the long-term impact of Medifast meal-replacement supplements combined with appetite suppressant medication (ASM) among participants who received a minimum of 12-weeks of treatment.
  
  
• RESULTS: Participants who completed 52 weeks of treatment experienced substantial weight losses at 12 weeks (-9.4 ± 5.7 kg), 24 weeks (-12.0 ± 8.1 kg), and 52 weeks (12.4 ± 9.2 kg), and all measures were significantly different from baseline weight (p<0.001 for all contrasts) for both true completers (n=34) and for ITT analysis (n=1,351). Fifty percent of patients remained in the program at 24 weeks and nearly 25% were still participating after one year. This weight-loss program using a combination of MMRS and ASM produced significant and sustained weight losses at 52 weeks. Results are better than those typically reported for obesity pharmacotheraphy in both short- and long-term studies, and are also better than those reported for partial meal-replacement programs. Program retention at one year was similar to that reported in many controlled drug trials and better than most commercial programs reported in the study.

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STUDY 5

• REFERENCE: National Institutes of Health. "Impaired Capacity to Lose Visceral Adipose Tissue During Weight Reduction in Obese Postmenopausal Women With the Trp64Arg B3- Adrenoceptor Gene Variant."
  
  
• PURPOSE: To examine whether women on a weight loss program who are carriers of a genetic variant (Trp64Arg) lose less visceral fat than women who do not have this gene. Participants entered a medically supervised weight loss program aimed at reducing body weight to less than 120% of ideal value. Food was self selected with dietitian supervision, with or without the inclusion of TakeShape^TM, a Medifast brand modified fasting supplement.
  
  
• RESULTS: Reductions in body weight, BMI, total fat mass and fat-free mass were not significantly different between carriers and non-carriers of the variant. Both groups experienced weight reduction of 31-36.1 pounds, which the study identified as a significant weight-loss effect.

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STUDY 6

• REFERENCE: Matalon, V. "An Evaluation of Weight Loss following a Carbohydrate and Fat Restricted Diet with Appetite Suppressant and Dietary Supplementation."
  The Bariatrician Summer 2000.
  
• PURPOSE: An open label trial designed to assess the safety and effectiveness of a weight-loss regimen consisting of a carbohydrate- and fat-restricted diet, supplemented with an appetite suppressant, a dietary supplement, and a liquid protein drink (Medifast). At baseline, evaluations included a history and physical, and measurements of total body weight (lbs), body fat (%), BMI, lean body mass, water weight and blood pressure. Patients were then seen weekly for 6 months. At each weekly visit, total weight, % body fat, BMI, lean body mass, water weight, and BP were noted. At the end of the study statistically significant differences from baseline to final value were noted for body weight (p<.001), percent body fat (p<.001), BMI (p<.001), lean body mass (p<.001), water weight (p=.01) and body systolic (p=.003) and diastolic (p<.001) blood pressure.
  
  
• RESULTS: Of 47 patients enrolled, 24 (51%) completed six months using the dietary regimen prescribed. Data was analyzed for all patients who were treated with the diet, as well as for the subset of patients who completed the entire study period. The dietary regimen showed that a carbohydrate- and fat-restricted program supplemented by a natural appetite suppressant can lead to progressive weight loss of comparable value to prescribed pharmacologic agents at the time of study. Patients in the study experienced statistically significant decreases in overall body weight, percent body fat, BMI, lean body mass, total body water and both systolic and diastolic blood pressure.

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STUDY 7

• REFERENCE: Davis, L. M.; Coleman, C. D.; Andersen, W. S.; and Cheskin, L. J. "The Effect of Metabolism-Boosting Beverages on 24-hr Energy Expenditure." The Open Nutrition Journal. 2: 37-41. 2008.
  
  
• PURPOSE: The effect of thermogenic meal replacement beverages (TMRB) containing 90 mg of EGCG and 100 mg of caffeine on resting energy expenditure (REE). Thirty adults (19 women, 11 men) were stratified into 3 groups: lean (n=10, BMI 21.5 ± 2.1), overweight/obese (OW) (n=10, BMI 29.8 ± 2.7), or weight maintainers (WM) (n=10, BMI 28.8 ± 4.0). Following an overnight fast, baseline measurements, including REE via indirect calorimetry, were performed. REE was repeated at 30, 60, 90, and 120 minutes after consuming a TMRB. Appetite was assessed via visual analogue scale at baseline, 30 minutes and 120 minutes after the TMRB.
  
  
• RESULTS: Mean 24-hour REE was increased 5.9 ± 2.5% overall (p=0.000), 5.7 ± 3.1% among lean subjects (p=0.0002), 5.3 ± 1.4% among OW subjects (p=0.000), and 6.8 ± 2.7% among WM (p=0.0007). Appetite was significantly reduced 30 minutes after the TMRB (p=0.0002). TMRB appear to be a promising weight control tool.

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