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Science sets Medifast and your weight-loss success apart from the rest.

Medifast is the brand recommended by thousands of health care providers.

Medifast has a long, clinical heritage of facilitating the weight loss success stories for thousands of customers. It's through our unique meal plans that we provide you with formulated nutrition and healthy habits for weight management.

Medifast Nutrition and How It Works to Make You Lose Weight

Medifast weight loss meals are nutrient-dense and fortified with 24 vitamins and minerals, so you can lose pounds and inches without losing out on nutrition. Each meal has essentially the same nutritional profile, and has been designed to have enough low-fat protein and healthy fiber to help you feel full and satisfied, without the between-meal hunger that can sabotage a weight loss plan.

The Key?

After a few days on either Medifast weight loss plan, your body will start to burn fat so you can lose weight while preserving muscle tissue.

Scientific Advisors to Ensure Continued Effectiveness

Medifast employs a Scientific Advisory Board that’s composed of a distinguished panel of scientists and doctors. Their role is to review the effectiveness, safety, and nutritional benefits of Medifast’s products and programs. The board also helps develop new meals and supplements and investigates alternate weight-loss approaches for those with special medical or nutritional needs, such as patients with heart disease or those who follow a vegetarian diet. We have options for just about anyone.

Clinical studies prove time and again that Medifast works.

  • Clinically proven effective by researchers at major universities.
  • Studies published in major medical journals have proven meal replacements to be an effective method of weight loss and weight maintenance.


Clinical studies prove time and again that Medifast works. Read the research here.*

Study 1

Obesity Science & Practice. Arterburn, et al.

In this 16-week study, participants were randomized to the reduced-calorie Medifast 4&2&1 self-guided plan, or a self-directed, reduced-calorie control diet. Differences in weight, body composition (DXA) and body circumferences, all measured monthly, were assessed by analysis of covariance with sex and baseline measures as covariates.

Study 2

International Journal of Obesity. Shikany, et al.

This study compared the Medifast Program to a conventional food-based diet of equal calories. Medifast resulted in significantly greater reductions in body weight and fat compared with a food-based diet for 1 year after randomization.

* All studies are based on the Medifast GO Plan (formerly the Medifast 5 & 1 Plan®) and Medifast Achieve Plan (formerly the Medifast 4 & 2 & 1 Plan®).