Anyone who's tried different weight-loss diets is probably familiar with their pitfalls. Low-calorie diets often leave you tired and hungry. Low-fat diets are also tough to follow and, contrary to popular belief, they do not seem to prevent heart disease.
Another diet trend, intermittent fasting, takes a different approach. Rather than limiting what you cat, this diet limits when you cat. It normally involves eating only during a certain time window, usually eight hours, over a single day. For example, you would eat only during the hours of 9 a. m. to 5 p. m. and then fast during the other 16 hours. For some people, that change may be easier to manage, says Dr. Eric Rim, professor of epidemiology and nutrition at the Harvard T. H. Chan School of Public Health.
Short-termism studies suggest that people stick to intermittent fasting diets as well as or better than they do to other diets. And according to a 2019 review article in the journal Nutrients, intermittent fasting promotes weight loss and may reduce risk factors linked to heart disease, including diabetes, high blood pressure, and unhealthy blood lipid levels.
"However, we are currently unsure about how well this diet works over the long term, "says Dr. Rim, noting that there are just two long-term studies of intermittent fasting, each lasting a year. Nor are there large populations of people who've followed this eating pattern for years. That's in contrast to two other diets linked to a healthy heart and healthy body size—the Mediterranean diet and a vegetarian diet.
Some experts add that intermittent fasting diets typically don't specify what foods you should eat. "As a nutritional epidemiologist, that makes me a little uncomfortable," Dr. David Mushen admits. Eating burgers and French fries five days a week and a single breakfast sandwich on your low-calorie day wouldn't be-healthy, he says. But with any diet, it's often a good idea to ease into the changes. You could start by trying a 5:2 diet or time-resisted eating. Once you start losing weight, you can gradually introduce more healthy foods, he suggests.
