Last updated December 11th 2016

While Medifast is supported by clinical evidence and appears to be effective at bringing about weight loss, it may not be a suitable weight loss program for all kinds of people.

Medifast is a weight loss program that claims to be very effective at helping people to lose a significant amount of weight. The program is comprised of meal plans which contain vitamins and minerals so that customers are able to lose a lot of weight without neglecting nutrients. The official website of the plan states that, after a few days, customers will enter into a state of fat burning which will lead to a high degree of weight loss. While the weight loss program does have clinical studies which have been carried out to support its claims, it is unclear whether the weight loss program is suitable for all kinds of people.

What is Medifast?

Medifast is a weight loss program that is designed to help customers achieve a significant amount of weight loss. The entire weight loss program consists of meal plans which are said to be tailor-made to help bring about fat burning whilst also performing a variety of other important functions including retaining muscle. The official website of the plan claims that it has been supported by over 20,000 different doctors since 1980 and is capable of leading to strong results whether you are looking to lose only a small amount of weight or a much larger quantity. They claim that their weight loss program is not designed as some kind of quick fix or instant weight loss solution and that it places a stress on long-term weight loss and continuing results that can be maintained over months and years.

In order to adhere to the weight loss program, customers are required to eat on six separate occasions each day, with 2 to 3 hours separating each meal. The meals are designed to be smaller in size compared to regular meals that you would associate with eating three meals per day, but this is something that is said to help lead to a more regulated and stable appetite. Out of these six meals, four of the meals are certified ‘Medifast Meals’. These meals are said to be the ideal proportion of carbohydrates, calories and proteins, whilst they are also said to contain all of the nutrients and minerals you need to ensure that you are able to achieve a balanced diet each day.

The official website claims that there are over 70 different meals to choose from ranging from soups, pastas and shakes. When becoming a part of the program, customers are able to personalise exactly what meals they receive so they are able to consume what they prefer most. On top of these four meals, customers are also required to consume two regular meals that are called ‘lean and green meals’. These are regular meals that customers will need to source themselves, although the weight loss program does provide a number of meal suggestions and recipes that customers can adhere to in order to ensure their meal is in keeping with the programs aims.

Finally, customers are also allowed to include a certified Medifast snack with one of their meals, something which is designed to give customers a treat and ensure that they are not left desiring foods that they love. This can be quite important as it may help to reduce food cravings and enable people to have the willpower to stick to the weight loss plan. This snack can either be chosen from a Medifast Snack range or customers can find their own snack including yoghurt or a baked potato.

Unlike some diet plans which provide very specific diet plans and instructions on what customers must be eating each day and each week, Medifast is a bit different in that there are a wide array of choices available and that the specific plan you follow is not set as you have some level of input on what you will be eating each day. However, you are expected to abide by some basic principles such as eating six meals per day and having the correct kinds of meals.

Although it appears that the official website encourages regular exercise and that many of the clinical studies they have published also include some degree of regular exercise, there is not actually an official exercise plan or any instructions on this area. However, in this regard, it appears that just some form of regular exercise is enough to qualify rather than having to stick to a specific exercise plan in order to lose weight.

How might Medifast help with weight loss?

Medifast may be capable of contributing towards weight loss in a number of different ways. Firstly, the way the entire plan is set out is believed to be an effective way at instigating weight loss as it encourages more frequent meals throughout the day in smaller quantities. Some evidence has found that there may be a link between increasing meal frequency and weight loss, although there is still much more research required on this area. While the weight loss program does advise this smaller but more frequent meal approach, this may not be enough on its own to lead to significant weight loss although this approach is believed to help increase feelings of satiety by helping to regulate and stabilise hunger levels.

The official website also claims that it is able to enable your body to enter into a mile to fat burning state, something that could help customers to significantly lower than body fat levels in order to bring about weight loss. In addition to this, it also claims that it is able to specifically preserve muscle tissue, as often muscle tissue is burnt up as a source of energy rather than body fat. By potentially helping to retain muscle mass, the product may not only help bring about weight loss but also allow people to achieve a more desirable body composition with lower body fat and highly muscle tissue.

Medifast meals may also be capable of contributing towards weight loss by having a positive impact on the metabolism. The official website claims that each of the meals contain a lot of nutrients including 24 vitamins and minerals, so that your body is receiving all of the nutrients that it needs in order to run healthily. It claims that the consequence of this is to help increase feelings of satiety by leaving you feeling full, while it also claims to be full of fibre and low fat protein which could further help contribute towards suppressing the appetite.

What clinical evidence is there?

There are an extensive number of clinical trials that have been carried out on the Medifast weight loss program and its special weight loss meals, in order to determine whether it is capable of helping to instigate healthy weight loss. The Medifast website publishes a number of different studies that have been carried out on the weight loss program and its meals. Some of the studies have also sought to compare the efficacy of a meal replacement diet compared to making changes to your food, an important difference that could play a key role in determining how much weight can eventually be lost.

One study was carried out on Medifast and aimed to look at a variety of effects that it had on the body. Over the course of this study, 310 overweight or obese participants were required to become a part of the Medifast weight loss program for a period of 24 weeks whilst a wide range of areas were looked at including body weight, fat mass and lean mass. The final results of this study found that participants on the plan showed significant improvements in all of these areas in addition to other areas such as blood pressure, suggesting that the diet plan may not only help to bring about weight loss but could also have important health benefits.

Another study on Medifast looked to compare the effect of the weight loss program compared to a food-based diet plan on a number of different areas including weight loss and weight maintenance. Over the course of this study, 90 obese participants were required to either follow the Medifast diet plan or to follow a separate food-based meal plan for a period of 16 weeks, whilst they were then monitored for a further 24 week period in order to determine whether they were able to stick to their weight or not. The results of the study observed that the level of weight loss was greater in the Medifast group by almost double compared to the food-based group. However, despite the fact that these are undoubtedly positive results, the level of weight regain was also higher in the Medifast group after the 16 week period, but that the level of overall weight loss was still greater compared to the food-based group. Another interesting results observed in this study was that the satiety levels were not seen to be different between the two groups.

Other studies have also found that the weight loss program appears to be capable of bringing about significant weight loss, while it is also important to note that almost no side-effects have been observed in any of these trials, suggesting that Medifast is safe for all kinds of people even over an extended period of time.


On the whole, Medifast appears to have the potential to bring about significant and sustained weight loss as can be seen from the range of clinical trials that have been carried out on the weight loss program. While the weight loss program does not actually provide customers with any supplements that are going to do any of the work, it does look to be a smart and well thought out diet plan that helps to instigate mild but prolonged weight loss over many weeks and months. Despite this, it may require significant willpower and dedication on the part of customers as the results do not appear to be instant and significant changes are required to your daily diet in order to experience any results.