MediFast Diet And Weight Loss: A Research Based Review

Just like the long list of weight loss pills, the weight loss industry provides you with a never-ending list of diets.

The Gale encyclopedia of diets provides the A to Z of diets.

And since we have promised you that we will be providing the real scientific data behind of all this, we will be doing exactly that.

And our target right now is Medifast diet.

If you visit the company’s official website you will see that this how the company defines Medifast:  ‘Medifast is a clinically proven safe and healthy weight-loss program.’

Medifast is a diet plan developed by Dr. William Vitale who used it as a therapy for those who needed to lose weight to ameliorate health-related conditions.

The website states that this diet has been used since 1980s and now it is being made available to everyone.

Medifast consists of a low calorie but high on nutrients diet which is safe and effective for weight loss.

Medifast is backed by a Scientific Advisory Board which evaluates the effectiveness, safety and nutritional value of the products.

What are the Medifast plans?

Medifast diets come under different plans that suit your calorie requirement.

Medifast 5 & 1

This was an old plan which involved eating 5 Medifast meal replacement and 1 meal of your own. The calories provided by this plan are around 1000 calories each day.

However, this plan has been revamped and now it is known as Medifast Achieve.

Medifast Achieve

This is the 4, 2 & 1 plan where you have 4 Medifast meal replacements, 2 meals, and 1 healthy snack.

Medifast meals include 70 options like bars, shakes, and soups which are rich in nutrients, low in calorie and balanced in carbohydrate and protein.

2 meals are lean and green meals which include five to seven ounces of lean protein, three servings of vegetables, and up to two servings of healthy fats.

These meals can be had at any time in the day and Medifast also provides a number of recipes and cooking suggestions for this meal.

Finally 1 stand for a healthy snack which could be a serving of fruit or yogurt or even one of the Medifast snacks.

Medifast Thrive

This plan is a weight maintenance plan and its a 3, 2 & 1 plan.  That would be 3 Medifast meals, 2 Lean and green meals and 1 balanced meal.

The balanced meal is made from options and depends on your daily calorie requirements.

Totally this plan provides 1800 calories and teaches the body to slowly increase calorie intake and maintain weight.

How does Medifast help with Weight Loss?

Medifast meal replacement plan is an extreme plan in terms of calories. It includes 6 meals that are spread out equally throughout the day (every 2-3 hours) to promote satiety.

Together the plan provides only a 1000 calories and the company claims that you can expect to lose 2-5 pounds per week for the first two weeks and 1-2 pounds per week thereafter.

When you consume fewer calories than what you require each day then you create a calorie deficit.

In this case, your body starts utilizing stored reserves of energy which is mainly fat

However, Medifast diet is extremely low in calories.

The low carbohydrate content of these meals puts your body in a state of ketosis.

Ketosis is a different metabolic state where the body produces ketone bodies from fatty acids in order to provide energy to the brain.

It is a fat burning mode which suppresses appetite and helps lose weight.

Additionally, Medifast provides Calorie Burn diet drinks which contain caffeine and epigallocatechin gallate which naturally boost metabolism and help in weight loss and Heart health supplements which contain omega 3 fatty acids that help lose weight.

Their meals are soy and whey based which are also said to cause weight loss. Light but regular exercise is recommended for better results.

Science on Medifast diet for Weight Loss

Medifast diet has been extensively researched on and additionally the company website itself provides a pdf which mentions 10 clinical studies conducted on Medifast diet.

So we will be going over these and more studies to check whether Medifast diet is clinically effective.

Medifast 5 & 1 plan helps you lose 5 times more fat than a food based diet

This study by David et al was conducted by the R&D team at Medifast, Inc. in 2010. The study compared the effect of meal replacement diet to an isocaloric conventional food based diet on body weight.

90 obese individuals were recruited for this study and were assigned to 16 weeks of weight loss followed by 24 weeks of weight maintenance.

They received either of the two low calorie plans: Medifast 5 & 1 Plan (MD) utilizing portion-controlled meal replacements or an isocaloric food-based plan (FB) using guidelines from the USDA Food Guide Pyramid, both providing  1000 kilocalories (kcal) per day.

The diet plans were as follows:

  • Medifast 5&1 plan (MD): 5 meal replacements (90-110 kcal/each), 5-7 oz lean protein, 1 1/2 cups of non-starchy vegetables, and up to 2 fat servings daily (providing 800-1000 kcal) low fat  low glycemic index (GI), low sugar, provided a balanced ratio of carbohydrates to proteins, and were either soy and/or whey protein based.
  • Food based plan (FB): 3 ounces of grains, 1 cup of vegetables, 1 cup of fruit, 2 cups of milk,5-7 ounces of lean protein, and 3 teaspoons of fat daily, multivitamin and additional calcium

After the weight loss phase, both groups entered a 24-week long maintenance phase, gradually increasing calorie intake to a maintenance energy level while the following the same diet plan.

At the end of 16 weeks, the average weight loss in MD group was 13.5kg while 6.5 kg in FB group.

According to the researchers: ‘MD participants lost five times more body fat and seven times more visceral fat, while maintaining more than twice the amount of lean muscle mass.’

Improvement in metabolic and inflammation parameters was also observed. The only limitation of this study was a drop-out rate of 43.2% in the Medifast group at 10 months.

Similarly Shikany et al studied Medifast’s 5 & 1 plan.

120 individuals were asked to follow a 26 week weight loss phase and then enter a 26 week phase of weight maintenance.

They either received a Medifast diet or food based diet.

At the end of 26 weeks weight loss was 7.5kg in Medifast group and 3.8kg in food based group. Reduction in fat mass and waist circumference were also greater in the Medifast group. Average reduction during weight maintenance was better in Medifast group compared to food based group.

What does this mean? Medifast 5 & 1 plan is proven to cause 5 times more body fat loss and 7 times more visceral fat loss than a diet plan based on USDA Food Guide Pyramid.

Medifast 4,2& 1 plan is clinically proven to cause weight loss

Recent research  on Medifast’s 4, 2 & 1 plan has also been published.

It was company sponsored.

In this stud,y a review of weight loss outcome in 310 overweight and obese individuals following this plan was conducted.

Average weight loss at 12 weeks was around 10 kg and at 24 weeks was 16kg. Good adherence to the plan and preservation of lean mass was also observed.

Additionally, improvement in the waist to hip ratio and blood pressure was also observed. Average weight regain was less than 2% in those who participated in the weight maintenance phase.

What does this mean? Company sponsored study demonstrates that Medifast 4,2 &1 plan causes weight loss of around 16kg in 24 weeks.

medifast diet

Medifast diet reduces the need of anti diabetic medications

In this John Hopkins university based study  , the effect of portion controlled meal replacement was compared to that of the standard diet in specifically type 2 diabetes patients.

Medifast has personalized plans for those suffering from diabetes and intending to lose weight. After 34 weeks of weight loss, weight maintenance for 1 year was observed.

At the end of 34 weeks, the portion controlled diet group lost on an average 16.1 pounds while standard die group lost 8.1 pounds.

So thats about twice the weight loss. More number of participants of portion controlled group lost around 5-10% of their initial weight and also reduced the use of anti-diabetic medication.

What does this mean? According to the study, Medifast diet helps diabetic patients lose weight and also reduces their dependency on drugs taken to treat diabetes.

It increases the effectiveness of appetite suppressants

This study  was conducted at Kansas City School of Medicine and the aim was to study the synergistic effect of Medifast meal replacements and appetite suppressants.

Appetite suppressants are drugs that act specifically on different gut hormones and brain chemicals in order to suppress appetite. Here is a detailed article as to how Appetite suppressants work?

This study lasted for 52 weeks and weight loss was gradually increasing. Average weight loss at the end of the study was 27.3 pounds.

Researchers concluded that the combination worked well and the results were better than those reported in studies focussed on anti-obesity drugs alone.

What does this mean? Medifast produces better weight loss results in combination with anti-obesity drugs than the drugs alone.

Medifast beverages raises metabolism

Among the 70 different options, Medifast provides a number of metabolism boosting beverages.

This study  is again by the R&D team at Medifast. What they studied this time was the efficacy of metabolism boosting beverages.

Coffee, green tea, yerba mate are few such natural metabolism boosting drinks. (Read Green tea for weight loss )

The meal replacement beverages contained 90mg ECGC, bioactive constituent of green tea and 100mg caffeine. The participants were classified as lean, obese and weight maintainers.

Overall the beverages brought about a 5.9% increase in metabolism (5.7% in lean, 5.3% in obese and 6.8% in weight maintainers).  Decrease in appetite and rise in fat oxidation was observed.

An open label clinical trial was conducted where obese individuals were kept for 6 months on carbohydrate- and a fat-restricted diet supplemented with an appetite suppressant, a dietary supplement, and a liquid protein drink (Medifast).

51% of the participants completed the study and the average weight loss was 24.9 pounds. Decrease in body fat was around 3.9% and a decrease in blood pressure was also observed.

This study was not typically focused on Medifast and the results were positive but since a number of weight loss agents are involved we can’t say that Medifast was responsible for weight loss.

What does this mean? Bioactive constituents of green tea and coffee are included in Medifast beverages and these help to raise the metabolism by around 5% and also decrease appetite. Also these drinks can be combined with other weight loss programs.

Medifast helps lose weight irrespective of your genetic configuration

Researchers at the University of Vermont, USA conducted a study  to examine the link between the tendency to gain visceral fat and variation in a gene.

For this they asked specific participants to follow a weight loss program of 1200 kcal with or without Medifast.

The results of this study were focussed on the variation of the gene but significant weight loss was observed.

At the end of 13 months weight loss was around 14-16kg and loss of body fat was around 10-11kg.

One way to interpret this study is that despite of genetic tendency to gain weight, individuals can still benefit from Medifast.

What does this mean? This study was focussed on variation of genes and its relation with visceral fat. However the results show that whatever be the genes Medifast can help you lose 10-11kg of body fat.

In house research on Medifast diet

In house data  collected by Medifast was reviewed over the years 2007-10 and its effectiveness was assessed.  % decrease in body weight was 12.3% which corresponded to 25.7 pounds and % decrease in body fat was 6.6% which corresponded to 23.5 pounds.

Researchers concluded that Medifast’s meal replacement plan, along with the support and accountability available in the Medifast Weight Control Center, is effective in promoting significant weight loss and improvements in body composition.

Another similar review revealed that weekly visits at Medifast’s Weight Control Center provide additional benefit over other conventional weight loss programs.

A clinical trial was conducted where obese women suffering from PCOS were asked to follow a Medifast diet for 3 months.

This study demonstrated that Medifast diet not only caused significant weight loss but also improved female fertility.

Medifast is also proven to be safe in children.

In this study children were assigned to Medifast meal replacement or USDA food guide Pyramid diet for 6 months following 1 year of weight maintenance.

No significant difference in weight loss existed in both groups and fat loss was in the range of 5.3-5.9%.

Also, a decrease in cholesterol was observed and no side effects were reported.

The scientists concluded: ‘Among overweight 8 to 15 year-old children, dieting with or without a parent, meal replacements were as safe and effective as a USDA food-based diet for weight loss and maintenance.’

Other sources of unpublished data reveals that Medifast diet followed for 6 months brings about significant weight loss in bariatric surgery patients and in those who intend to lose weight but have health problems apart from obesity.

What does this mean? In house research on Medifast reveals that support provided at Medifast Weight loss centers provides a bonus to clients and helps with weight loss. Medifast also works well for bariatric surgery patients and is safe for children.

What are the added advantages of Medifast diet?

The company very well answers the question as to why you should choose Medifast over other weight loss programs:

  • It’s fast.
  • It’s satisfying.
  • It’s simple
  • It’s safe.
  • It’s long term.
  • It’s supported.

One of the best parts of Medifast diet is that it involves 6 meals spread out at equal intervals so that destroys the mental notion of dieting and starvation.

The other great factor is the constant support the company provides by counselling and guiding and they also run forums where you can get a lot of information from other users.

They also have specialized plans for depending on your requirement like in case of diabetes, seniors, teens etc.

They also provide suggestions for the meals that you need to cook and also in case you are dining out.

Concerns about Medifast diet

The primary concern about Medifast diet is that it is a meal replacement strategy. Most individuals are not comfortable with meal replacements.

However, the plan offers 70 varieties which includes bars, smoothies, soups and even cheese puffs, perhaps much more.

Next, the plan provides only 1000 calories during weight loss which is a pretty extreme transition. So it is advisable to consult your doctor before following Medifast.

The products contain soy so in case your allergic to it you might want to avoid that. The company provides a great deal of information on possible allergens.

While surfing through the different products they had to offer a few of the desserts had around 9 grams of sugar per serving.

That’s a little too much sugar from one source considering AHA recommends 6 teaspoon for women and 9 for men.

Also, there is not adequate data available about the weight maintenance phase and the possible weight gain that might occur during that phase.


Medifast is one of the most versatile plans that the industry has to offer but you can’t ignore the fact that it is a meal replacement strategy and is extremely low in calories.

So it depends on your preferences and tolerance levels as to whether this will work for you or no.

Overall the nutrition labels suggest that it is indeed a healthy, balanced and safe meal for weight loss.

And the clinical evidence is also strong enough. If you have tried it we would love to hear your experience.

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