New research suggests eating early and within a 10-hour window is healthier
Researchers have provided more evidence that eating earlier in the day might be good for you – and eating all of your meals within a 10-hour window could be healthier, too.
Participants who ate meals four hours later in the day were more hungry, burned calories at a slower rate, and had body changes which promoted fat growth, according to a study from researchers at Brigham and Women’s Hospital, published this week in the peer-reviewed journal Cell Metabolism.
“In this study, we asked, ‘Does the time that we eat matter when everything else is kept consistent?’” said first author Nina Vujovic, a researcher in the hospital's division of sleep and circadian disorders, in a description of the research on the hospital's website. “And we found that eating four hours later makes a significant difference for our hunger levels, the way we burn calories after we eat, and the way we store fat.”
Researchers had 16 overweight patients eat the same exact meals on two different schedules: one with meals earlier in the day, and the other with meals about four hours later in the day. (For example, a participant in the early group might eat at about 9 a.m., 1 p.m. and 5 p.m.; the other group at 1 p.m., 5 p.m. and 9 p.m.)
Participants logged their hunger and appetite. Researchers gathered blood samples, body temperature, energy expenditure, and took samples of body fat tissue from some subjects.
Late eating more than doubled the likelihood of being hungry, researchers said. When study participants ate later in the day, they had lower levels of the hormone leptin, which is present when we feel full, researchers said.
Genetic tests also suggested fat growth accompanied later eating. Eating late resulted in about 60 fewer calories being burned, the study says.
“We wanted to test the mechanisms that may explain why late eating increases obesity risk,” senior author Frank Scheer, director of the medical chronobiology program in Brigham's division of sleep and circadian disorders, said in a statement.
The study is small, but was specifically designed to assess eating schedules' effects on the body. Researchers hope to expand on the findings.
“This study shows the impact of late versus early eating. Here, we isolated these effects by controlling for confounding variables like caloric intake, physical activity, sleep, and light exposure, but in real life, many of these factors may themselves be influenced by meal timing,” Scheer said. “In larger scale studies, where tight control of all these factors is not feasible, we must at least consider how other behavioral and environmental variables alter these biological pathways underlying obesity risk."