Intermittent fasting is the hottest dieting trend since keto. (Bonus points if you’re keto and intermittently fasting. You can probably fly now!) The gist is that people attempt to lose weight by only eating between certain hours, or they restrict their eating on certain days of the week while allowing themselves to eat normally the rest of the time. That’s the “intermittent” part: Eat regularly most of the time, restrict your eating other times. Then there’s a subset of intermittent fasting known as the 5:2 diet, in which people eat regularly five days of the week and take in a very restricted number of calories on two days.
But while these diets have gained popularity, there have been only a few longitudinal studies on whether they actually lead to sustained weight loss. (U.S. News & World Report has a breakdown of past research into fasting diets.) Now there’s a new credible study to add to the mix: This 50-week study of 150 obese and overweight adults published in The American Journal Of Clinical Nutrition found that the 5:2 fasting diet was “equivalent but not superior to” conventional dieting in terms of weight loss and the prevention of metabolic diseases.
To conduct the study, researchers divided the 150 individuals into three groups: a control group that wasn’t asked to change their diets; a group that followed the 5:2 diet; and a group that followed a more conventional diet of continuously restricting their calorie intake by 20 percent. During the first few months of the experiment, a nutritionist monitored the participants to make sure they adhered to the diets; the next few months saw the participants monitor their own diets.
The findings were encouraging for both dieting groups, because they showed that conventional and fasting diets both do lead to weight reduction. However, the results could be considered a disappointment for those hoping that the fasting diet would be a superior option. Turns out the simplest advice is still generally correct: Eat fewer calories, and you’ll lose weight.