When you snooze, you don’t necessarily lose.

A U of C study released on Tuesday found that more sleep correlates to faster metabolisms and that less sleep may even result in weight gains.

During the study, a group of seven subjects slept for 4.5 hours while another slept for 8.5 hours for four consecutive nights. One month later, the groups switched. After measuring the blood and body fat of the two groups, researchers observed that those who only got 4.5 hours of sleep had a 17 percent reduction in insulin sensitivity compared to those who got the extra four hours.

“We had healthy, fit 20-year-old volunteers and turned them into 40-year-olds metabolically,” said Matthew Brady (A.B.’87, Ph.D.’94), the author of the study and Vice-Chair of the Committee on Molecular Metabolism and Nutrition.

Sleep deprivation also decreased the amount of the hormone leptin in the body, making subjects feel more hungry. While the study did not examine why sleep deprived subjects displayed increased insulin resistance, Brady hypothesized that it could be a response to stress or reduced production of the protein AKT, which affects how the body processes glucose and insulin.

“This is borne out in real life. When you’re up until one or two studying for midterms, you don’t get hungry for carrots or brown rice, you want to eat pizza or ice cream,” Brady said.

Brady said researchers think the metabolism of college students will recover once they start sleeping more again.

“What we’re really interested in though is if changing the sleep habits of forty year-olds will have as significant of an effect on their health, and if it can help reverse some of the effects of metabolic diseases,” he said.

Brady acknowledged that the study had a small sample size but emphasized the strength of the results.

“The results are very clear,” he said. “People think they can get around sleep deprivation, but that’s not what we found.”