Intermittent fasting (IF)—the practice of abstaining from food for limited periods—is growing in popularity as a dieting fad. Two main types of IF are the 5:2 diet and time-restricted feeding. On the 5:2 diet, a person eats normally five days of the week and then eats just one meal a day on two nonconsecutive days. Time-restricted feeding involves fasting for about 16 hours a day, with an 8-hour eating window, usually from 10 a.m. to 6 p.m.
Some people are attracted to IF as a way to lose weight because it doesn’t require calorie-counting. However, fasting can cause headaches, fatigue, and lightheadedness. Fasting at certain times may lead to overeating at other times. This practice is dangerous for people with certain health conditions, such as diabetes.
In the short term, according to the American Heart Association, IF does not help people lose weight or lower their cholesterol levels any more than conventional methods of dieting do. The long-term effects of this way of eating are unknown.
If you are interested in exploring proven and safe methods of weight control, visit the Weight-control Information Network (WIN). Consult your doctor before beginning any weight-control program.