Does Intermittent Fasting Work?

The logical conclusion used to be that, to lose weight, you had to starve yourself. Then, when we began to understand the dreaded “starvation mode” the popular thinking said that the secret to losing weight was to actually eat more. This thinking generally encouraged six small meals a day to jump start your metabolism. But, recently, a new trend has cropped up that challenges this idea: Intermittent fasting (IF). What is IF? Does it work? Could you benefit from working it into your training?


What is it?

Intermittent fasting is exactly what the name suggests: regularly going without food. The exact form the fast takes, though, depends largely on you. The two primary methods are the periodic fast and the daily fast.

The periodic fast requires that you take a full 24 hours offer from food. But, exactly how often you do this is somewhat up in the air. Some people do it once per year, occasionally for religious reasons, others do it as frequently as once per week.

The daily fast is a shorter fast that is incorporated into your daily schedule. Usually, it consists of a 16 hour fast and an 8 hour feeding window. For example, if your first meal is at 9am,, your last meal of the day would be at 5pm.


What Does it Do?

One of the most difficult questions to answer when it comes to any diet is “Does it work?” Basically, any diet that forces you to eat less will help you lose weight. For a while, at least. So in order to decide whether or not a diet works, you first have to decide what you expect it to do.

As mentioned, restricting your calories through fasting will, most definitely help you lose weight. But, proponents of IF promise much more than weight loss. Its supporters claims that IF can help you balance your insulin response, which affects several hormones and that it will encourage a lean, muscular appearance. It’s also been stated that IF can even help you live longer and improve your cardiovascular health.

Surprisingly, most of the evidence supports these attractive benefits promised by intermittent fasting programs. Numerous scientific studies have found that IF increases insulin-sensitivity, which helps to mediate blood sugar levels. Insulin resistance is a major red-flag in the development of type-2 diabetes so, IF may have potential in preventing diabetes.

This increased sensitivity to insulin also means that nutrients are getting to your muscles faster and more efficiently. When your muscles are well-fed they grow and recover more quickly, which will in turn burn fat. However, this detailed effect of IF is not totally proven, or disproven, in clinical trials. It’s worth noting that most of the support for these claims comes from anecdotes.

As usual, the “longer, healthier life” claims are very difficult to come to a clear decision on. Some studies have shown that a restricted-calorie diet can actually shorten life-span, while others disagree. A few studies have even linked IF with an unexplained hardening of the walls of the heart, leading to a decrease in the heart’s efficiency. Since IF is a relatively new fitness phenomenon, there’s little clear understand as to the long-term effects. These findings may shed a discouraging doubt on the usefulness of intermittent fasting.

Women may also want to use some extra caution. Many animal and human studies have found unique risks for women, including a decrease in heart health and increase in LDL cholesterol. Because of these risks, most experts recommend that women use a 14 hour daily fasting program.

Have you tried intermittent fasting? Please share your experience with us in the comments!







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About jonathan.thompson

Jonathan Thompson is a Certified Personal Trainer and Running Coach with the American Council on Exercise, specializing in nutrition. In addition to his real-world experience working with clients, his articles and blogs on fitness advice have been published on many websites and magazines.