Intermittent fasting—which for some people may mean skipping breakfast and restricting their daily eating period to only eight consecutive hours—is one of the most popular diet trends in the last couple of years. But new research suggests that what you eat, rather than when you eat, has a greater impact on one's overall health and ability to lose weight, according to a new study from the American Heart Association.
"We have wondered for a long time if when one eats during the day affects the way the body uses and stores energy," said study author Nisa M. Maruthur, M.D., M.H.S., associate professor of medicine, epidemiology, and nursing at Johns Hopkins University in Baltimore. "Most prior studies have not controlled the number of calories, so it wasn't clear if people who ate earlier just ate fewer calories. In this study, the only thing we changed was the time of day of eating."
Credit: Lennart Weibull
Related: Science Says Exercising in the Morning May Be Best for Weight Loss
Maruthur and his team of researchers studied 41 overweight adults over the course of 12 weeks. All participants consumed the same pre-prepared, healthy meals provided for the study; 90 percent of the participants were Black women with prediabetes or diabetes, and an average age of 59 years. Half of the adult participants followed a time-restricted eating pattern, limiting their eating to specific hours of the day and ate 80 percent of their calories before 1 p.m. The other half of the participants ate at the usual times during a 12-hour window, consuming half of their daily calories after 5 p.m.
Participants' weight and blood pressure were measured at the beginning of the study and again at the four-, eight-, and 12-week mark period. Researchers found that both groups lost weight and had decreased blood pressure due to the type of healthy food that they consumed, not the time at which they ate it.
"We thought that the time-restricted group would lose more weight," Maruthur said. "Yet that didn't happen. We did not see any difference in weight loss for those who ate most of their calories earlier versus later in the day. We did not see any effects on blood pressure either."