Meal timing strategies such as intermittent fasting or eating earlier in the day appear to help people lose weight by lowering appetite rather than burning more calories, according to research published in the journal Obesity.
The study is the first to show how meal timing affects 24-hour energy metabolism when food intake and meal frequency are matched.
Eric Ravussin, one of the study’s authors, said: “Coordinating meals with circadian rhythms, or your body’s internal clock, may be a powerful strategy for reducing appetite and improving metabolic health.”
“We suspect that a majority of people may find meal timing strategies helpful for losing weight or to maintain their weight since these strategies naturally appear to curb appetite, which may help people eat less.”
The researchers also report that meal timing strategies may help people burn more fat on average during a 24-hour period, though these results are preliminary. Early Time-Restricted Feeding – a form of daily intermittent fasting where dinner is eaten in the afternoon – helped to improve people’s ability to switch between burning carbohydrates for energy to burning fat for energy, an aspect of metabolism known as metabolic flexibility.
During the study, 11 adult men and women who had excess weight were recruited. Participants tried two different meal timing strategies in random order: a control schedule where participants ate three meals during a 12-hour period with breakfast at 8:00 a.m. and dinner at 8:00 p.m. and an eTRF schedule where participants ate three meals over a six-hour period with breakfast at 8:00 a.m. and dinner at 2:00 p.m. They participants followed the different schedules for four days in a row. Although eTRF did not significantly affect how many calories participants burned, the researchers found that eTRF did lower levels of the hunger hormone ghrelin and improved some aspects of appetite. It also increased fat-burning over the 24-hour day.
Hollie Raynor, PhD, RD, LDN, who was not associated with the research, said: “this study helps provide more information about how patterns of eating, and not just what you eat, may be important for achieving a healthy weight.”