Due to the nature of the medifast diet it is possible to lose large amounts of weight in a relatively small period of time and as such I suppose it could be classified as a crash diet. The medifast diet works two different ways, firstly by creating an energy deficit with low energy meals, and secondly by forcing the body into ketosis by providing insufficient usable sugars or carbohydrates.

The idea of being in a state of energy deficit for a long period of time is not fantastic for the body as it activates survival mechanisms in the body which in the long run lowers the body’s metabolic rate by making the organs do more work with less energy. This is a homeostatic response known as down regulation and can be overcome having one day a week when you eat whatever you like. This is not recommended by the good people at medifast, however it does make sense as an exit strategy from the diet as you don’t want to come of the diet with a turtle paced metabolism or you will see the weight coming straight back.

Another not so healthy side to the diet is prolonged ketosis within the liver, this is a double edged blade as the ketosis is the reason that people are able to loss fat so quickly on this diet as compared to a simple reduced calorie diet, but it also places a constant strain on your liver and the acid which is produced as a by-product of the ketosis places quite a large strain on your kidneys, lungs, heart and arteries which are trying to remove the acids from your body as quickly as possible.

As you can see the medifast diet does place a strain on your body in ways that can be considered unhealthy, but so does being fat and many people justify the short term strain placed on their bodies by weighing them against the long term health benefits of carrying less fat directly around their vital organs.

The most important aspect of the medifast diet is not whether or it will work. It will work if you stick to the directions. The most important part is when and how to get off the program. One thing that yoyo dieters worldwide have learnt is that losing weight is not as hard as keeping it off, as such I recommend setting your target weight then weaning yourself off the diet when you reach this weight by slowly introducing equal quantities of exercise and regular foods as reduce the number of medifast meals you have a day. The best exercises to introduce are walking or bicycling as neither are particularly hard on the body.

This article is an overview of the medifast product, if you wish to know more medifast diet is a great information source.