While ample sleep is an undisputed muscle-building necessity, whether you should be eating before you do hit the hay is a more controversial topic. New findings show that people who tend to eat later at night are more likley to gain weight, have higher levels of insulin and cholesterol, and have a lower fat metabolism, according to University of Pennsylvania researchers at the Perelman School of Medicine.

In the study, nine healthy-weight people spent eight weeks following a “daytime eating” schedule, consuming all of their meals between 8 a.m. and 7 p.m., then eight weeks following a “delayed eating” schedule and consuming their meals between 12 p.m. and 11 p.m. In between, there was a two-week washout to make sure that the first eight weeks didn’t carry over into the latter. Each of the participants had metabolic measures taken and blood drawn to monitor his or her metabolic and hormonal changes. Researchers found that the late eaters gained weight and metabolized less fat. Insulin, fasting glucose, cholesterol, and triglyceride levels also suffered during the delayed eating schedule. The groups’ sleep schedules were kept the same.

“Eating later can promote a negative profile of weight, energy, and hormone markers—such as higher glucose and insulin, which are implicated in diabetes, and cholesterol and triglycerides, which are linked with cardiovascular problems and other health conditions,” lead author Namni Goel, Ph.D., a research associate professor of psychology in Psychiatry in the school’s division of Sleep and Chronobiology, told Penn Medicine News.

Researchers found that eating earlier correlated with being in overall better condition, so maybe it’s time to stop making those late-night fast-food runs.

“While lifestyle change is never easy, these findings suggest that eating earlier in the day may be worth the effort to help prevent these detrimental chronic health effects,” said senior author Kelly Allison, Ph.D., an associate professor of psychology in Psychiatry and director of the Center for Weight and Eating Disorders at the university. “We have an extensive knowledge of how overeating affects health and bodyweight, but now we have a better understanding of how our body processes foods at different times of day over a long period of time.”