Meal Timing May Change Body Composition, Not Performance

Researchers combined 16 randomized trials covering 245 athletes. They compared a 16:8 time-restricted eating pattern—food during eight hours and fasting during the remaining 16—with more conventional meal schedules. The review tracked weight, fat, muscle, strength, stamina, power, and aerobic fitness.

The 16:8 groups showed modest decreases in weight and body fat, while muscle mass remained largely unchanged. Exercise results were also similar between groups, including measures of strength, muscular stamina, power, and aerobic capacity. Elite athletes had somewhat greater shifts in weight and fat than recreational athletes, although the evidence was insufficient for a firm conclusion.

The findings carry limits because many trials involved few participants and lasted only a short time. Evidence certainty varied from very low to moderate. A shorter daily eating period might reduce calorie intake, so fasting itself may not be responsible for the body-composition differences. An eight-hour window can also make adequate calorie and protein intake, workout fueling, and recovery harder. The trials were not long enough to establish the effects of repeatedly falling short of those training needs.