Turns Out Intermittent Fasting’s Best Trick Is the Closed Kitchen

By Mark J Kaylor

Turns out much of intermittent fasting’s success comes down to something simple: a shorter eating window usually means eating less.

In a year-long trial published in the New England Journal of Medicine, researchers in China randomly assigned 139 adults with obesity to one of two plans. Both groups followed the same daily calorie target. One group also ate only between 8 a.m. and 4 p.m.

After 12 months, the time-restricted group had lost about 17.6 pounds on average, and the calorie-only group about 13.9. That gap wasn’t statistically significant, and the groups looked similar on body fat, blood pressure, and metabolic markers. The authors concluded that eating fewer calories explained most of the benefit.

That’s good news if fasting suits you. “The kitchen closes at four” is a simple rule, and simple rules are easier to keep than counting every bite. The clock is a useful tool. It just doesn’t seem to have much extra magic of its own.

The trial was too small to rule out a modest extra benefit, so the question isn’t fully closed.

Turns out the best part of fasting may be the “closed” sign.

Reference: Liu D, Huang Y, Huang C, et al. Calorie restriction with or without time-restricted eating in weight loss. New England Journal of Medicine. 2022;386(16):1495-1504.