What Are the Potential Benefits of the Alternate Day Diet?

Kelly Ferguson
Kelly Ferguson
Woman doing yoga
Woman doing yoga

The alternate day diet is a diet plan focused on helping people lose weight through calorie restriction. Weight loss in general can cause an improvement in many areas of health, including blood pressure, cholesterol, and insulin resistance. If the alternate day diet succeeds in helping you lose weight, you can expect to see improvements in all these areas, plus other weight loss related benefits such as a reduction in sleep apnea and increased energy. The author of the book that introduced the alternate day diet, Dr. James Johnson, also claims that the severe calorie restriction experienced during the diet provokes the activation of the SIRT1 gene, which is purported to aid in weight loss, slow aging, and reduce inflammation and disease.

Depending on which version of the diet you follow, every other day you are either supposed to eat as you normally would or you are free to eat as much as you like with few limits. For this reason, the alternate day diet tends to provide frequent enough rewards that it is reportedly one of the more pleasant diets to be on. Some people treat it as a lifestyle more than a temporary diet, and frequently enjoy doing so. If you believe you will be able to dramatically restrict your calories every other day, commonly to 500 calories or less while actively trying to lose weight, you may find the alternate day diet beneficial.

Some people find the diet very motivating because it is relatively easy to follow for an extended time. Psychologically, diet success can provide a huge boost of self-esteem for people so used to failing at diet plans. Also, people tend to put forth more effort in the form of exercise if they are able to follow through with a successful diet plan that proves that weight loss is possible and achievable. Also, the increased calorie intake on high calorie days might provide more energy to put toward exercising than regular steady diets with a constant, low calorie limit.

People who prefer to lose weight using methods other than pure calorie restriction may find the technique used in the alternate day diet useful. For example, instead of having a diet day where you restrict your calories dramatically, aim to eat fewer grams of carbohydrates or saturated fats. You may not be restricting your calories to the level needed to activate SIRT1, but you will likely experience some weight loss and health benefits due to your diet modifications.

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Discussion Comments


@bythewell - I can see ways in which this diet could do harm. It doesn't seem to do anything to teach people to eat healthily.

They might lose weight, sure, but if they spend their non-fasting day living on sodas and cakes they'll still end up with obesity related diseases, because they'll be taking in fat and sugar without adequate amounts of fiber.

Dieting is almost never a good idea. It implies a short term solution. I'm not entirely against the idea of fasting, but people need to make sure they are eating enough vegetables and fruits and other healthy things when they aren't fasting.


@umbra21 - There have been quite a few studies on rats showing that if their calorie intake is restricted for most of their lives to about 80% of what they would normally eat, they live quite a bit longer than they normally would.

They think that fasting like this is a way for people to achieve the same effect, even without the goal of weight loss.

Of course, you'd have to have long term studies to back it up and I don't think they've been researching it long enough to have hard data for humans.

But at least this kind of diet doesn't seem like it could do much harm.


When I first heard about this I thought it was a bit of a con really. Any diet which tells you to not eat seems that way to me, as they never work in the long term and tend to make you lose muscle mass and be miserable while you're on them.

But when I researched this one, it turns out it actually has quite a bit of scientific data attached to it.

There haven't been any studies of this particular method of alternate day "fasting" but people have been doing every other day diets for a few decades now with some positive results.

I don't know about it activating a gene, but it tends to help people lose weight, without feeling guilty about breaking their diet, as they are allowed to "break" it all the time. And since there are so many days where they can pretty much eat what they like they don't tend to lose muscle mass or become vitamin deficient either.

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