Early time-restricted eating: does the time of day you eat matter?

Intermittent fasting is linked to better heart and metabolic health. But is that only because people lose weight? To find out, Elizabeth Sutton, Courtney Peterson and colleagues ran the first supervised trial of early time-restricted eating: fitting all your meals into the early part of the day, in line with the body's daily rhythms. Participants were given enough food to keep their weight stable, so any change couldn't come from weight loss.

Men with prediabetes tried two schedules for five weeks each, in random order. One was early time-restricted eating, with a six-hour eating window and dinner before 3 p.m. The other was a usual 12-hour eating window. The early schedule improved insulin sensitivity, the response of the insulin-making cells in the pancreas, blood pressure, oxidative stress and appetite, without any weight loss.

The researchers describe it as a proof-of-concept study. It suggests that the benefits of intermittent fasting don't come from weight loss alone, and that when you eat may matter too.

General information, not medical advice. Don’t fast without talking to a doctor if you’re pregnant or breastfeeding, under 18, have had an eating disorder, have diabetes, or take insulin or other medicine that lowers blood sugar.