Pros and cons of intermittent fasting

The obesity epidemic has spawned a cottage industry of weight-loss schemes. Currently in vogue is intermittent fasting, which involves alternating intervals of extreme calorie reduction with periods of normal eating. Proponents of an intermittent fasting regimen claim that it helps shed pounds faster than traditional diets, as well as reduce inflammation and other heart disease risks.

What is intermittent fasting?

All diets achieve weight loss through the same equation — you take in less food energy each day than your body burns for normal activity. Intermittent fasting achieves this goal by severely limiting calories during certain days of the week or during specified hours during the day. The theory is that intermittent fasting will help decrease appetite by slowing the body's metabolism.

Fasting for weight loss?

So far, the research studies evaluating intermittent fasting have been relatively short and have enrolled only a limited number of participants. In one, 100 overweight people were assigned to one of three eating plans: restricting daily calorie intake by the same amount every day, fasting on alternate days, and continuing with normal eating habits. At the end of the 12-month study, both diet groups had lost weight compared with the normal eaters. However, the fasters didn't fare any better than the conventional calorie cutters.

Potential pitfalls of intermittent fasting

A notable aspect of this trial was a very high dropout rate (38%) among the people assigned to the fasting regimen. This may reflect a real-life pitfall of fasting as a weight-loss approach. In addition, there's a strong biological push to overeat following fasting periods. Your appetite hormones and hunger center in your brain go into overdrive when you are deprived of food.
While it's true that getting rid of excess body fat will improve a person's metabolic profile and lower cardiovascular risk, there's no strong evidence that fasting adds health benefits beyond any other weight-loss strategy.

Who should not try intermittent fasting

If you are considering intermittent fasting, make sure to discuss it with your doctor. Skipping meals and severely limiting calories can be dangerous for people with certain conditions, such as diabetes. People who take medications for blood pressure or heart disease also may be more prone to electrolyte abnormalities from fasting. Also, we live in a toxic, obesogenic food environment. So you'll need a strong social support network to endure very low-calorie days over the long haul.
 

Sources: Harrvard