The Spanish study finds that dieters who ate their main meal before 3 p.m. lost significantly more weight than those who ate later in the day. This held true even though the early eaters were eating roughly the same number of calories during the five-month weight-loss study as their night-owl counterparts.
On average, the early eaters in the Spanish study lost 22 pounds, compared with the late eaters who lost 17 pounds. Both the early eaters and late eaters had similar levels of physical activity and got similar amounts of sleep, so researchers ruled out these factors as possible explanations for the differences in weight loss.
In the study, the people who ate late and didn’t lose as much weight also tended to skip breakfast or eat just a little in the morning.