Limiting eating to an 8-hour period with caloric restriction produced greater short-term weight loss

Reference

Jamshed H, Steger FL, Bryan DR, et al. Effectiveness of early time-restricted eating for weight loss, fat loss, and cardiometabolic health in adults with obesity: a randomized clinical trial. JAMA Intern Med 2022;182(9):953-962.

Synopsis

These investigators enrolled 90 participants who were recruited from a weight-loss medicine clinic. All participants received one-on-one counseling from a dietitian at baseline (60-minute session) and at weeks 2, 6, and 10 (30-minute sessions), and were asked to attend 10 group sessions. They were given a hypocaloric diet (500 kcal below resting energy expenditure) and encouraged to exercise. Participants were randomly assigned (concealed allocation uncertain) to eating at typical times (ie, throughout the day) or to eat only early in the day (between 7:00 and 15:00). Self-reported food intake and exercise were similar between the 2 groups, although (by calculating average fat loss) the early day eaters theoretically ate 250 fewer calories daily. Using intention-to-treat analysis, participants in both groups lost weight over 14 weeks, though to a greater degree in the early-day-eating group (-4.0 kg vs - 6.3 kg; P < .001). However, there were no differences in absolute fat loss. When analyzing only people who completed the study (75% - 80% in each of the groups), weight loss and body fat loss were significantly greater in the early eaters.