The health and wellness industry is constantly evolving, with new research coming out almost daily finding physiological benefits of one program or another. One trend that has been gaining attention in recent years is the concept of intermittent fasting.
Intermittent fasting is the practice of periodically fasting for 18-24 hours with periods of normal calorie consumption in between. In a research setting, intermittent fasting has been shown to promote weight loss as well as some possible prevention of chronic disease. These discoveries have led to an effort by health and wellness professionals to market this practice.
Although intermittent fasting can have some beneficial effects, it is important to understand how and why these effects take place in order to make an informed decision on whether, and to what degree, you include intermittent fasting into your regular routine.
We all know that calorie restriction works as a method of weight loss, as energy cannot be created or destroyed. If you eat less than you use you will decrease in weight. Calorie restriction has been shown to not only lower body weight but it also has been shown to reduce oxidative stress on the vital systems in the body (i.e the brain, heart, liver, and muscles) — meaning it reduces the effects of aging.
While intermittent fasting as a form of calorie restriction does show similar effects, in practice health benefits seem to be limited due to little or no change in the total calories consumed over time. Intermittent fasting calls for little to no food for 18 to 24 hours but it does not usually specify how much food can be eaten on the other days. This means that often people who participate in diets that include intermittent fasting tend to overeat on the days they are allowed to eat — which leads to an equal or increased weekly caloric intake, ultimately leading to maintaining or increasing body weight over time. The first thing to do when taking on a diet that includes intermittent fasting is to make sure that the weekly calorie intake is consistent with your goals (i.e. eat fewer calories than normal in order to lose weight).
Intermittent fasting has also gained headlines because of its effects on oxidative stress to certain tissues in the body and its effects on the aging process. While calorie restriction has been shown to have a positive effect on the levels of oxidants in the body and ultimately a slower aging process, intermittent fasting has shown mixed results in this area. With intermittent fasting, some vital organs such as the heart show a decrease in oxidative stress while others such as the brain, liver, and musculature will have an increase in oxidative stress which is one of the main contributing factors to the aging process. Other health benefits such as changes to insulin sensitivity and energy production have also shown that Intermittent fasting is less effective than calorie restriction. Studies have shown that calorie restriction can increase your body’s sensitivity to insulin making blood sugar levels easier to control while intermittent fasting has been shown to decrease insulin sensitivity making blood sugar levels less stable. These differences, just like with weight loss, are usually due to overeating on the unrestricted days. While intermittent fasting has been shown to have some health benefits, most of these benefits are related to overall calorie restriction.
The physiological benefits of intermittent fasting are limited, but it can be used as an effective form of weight loss as long as the daily and weekly calorie intake is lower than needed to maintain body weight. So if you are going to try intermittent fasting as a diet plan make sure you are using this practice to restrict weekly calories and not simply overeating some days and under eating on other days.
Next time you hear of a new fitness trend or a hot new diet, take a few minutes to ask why this might be beneficial. It is easy for the results of scientific research to be misinterpreted, even by professionals, and it is easy to lose your way when trying out a new program. Before you begin any diet or exercise program always be sure to review your options with your physician to make sure you are making informed decisions.
Joe Phelan is the sales manager of Power Hour 360, a fitness center.