Students may want to rethink pulling all-nighters for upcoming tests, as a new study links lack of sleep to excess eating.

The American Heart Association announced its findings during a presentation in San Diego, which showed that those who got about a third less than their average amount of sleep consumed more than 500 additional calories a day on average.

“Sleep loss can lead to hormonal changes that can set the stage for increasing appetite and preference for high-starch foods, which can set the stage for obesity,” said Dr. Sairam Parthasarathy, an associate professor of medicine at U. Arizona. “Sleep deprivation or interruption can lead to hormonal changes that lead to such eating behavior.”

In the study, 17 people aged 18 to 40 were asked to record their eating and sleeping patterns. Subjects were monitored at home as well as in a lab for varied amounts of time on different nights. Subjects in the study were allowed to eat as much as they wanted. In a comparison of a test group that slept 5.2 hours a night and a test group that slept 6.5 hours a night, the researchers found that the first test group ate an average of 143 more calories per day than the subjects who slept more.

“Sleep deficiency alters hormones in the body that control appetite, leading to an increase in hunger,” said Dr. Stuart Quan, professor emeritus from the College of Medicine and retired associate director of Respiratory Sciences. “Especially foods that have a high carb content.”

Some students said they saw the study’s results reflected in their own lives.

“I notice that the less sleep I get, the more I eat the next day,” said Dylan Trujillo, a freshman studying public management and policy. “It’s like I need the extra food to give me the energy to get me through the day.”

The National Sleep Foundation recommends that individuals get seven to nine hours of sleep a night. Healthy adults sleep on average between 8 and 8.5 hours a night, according to the National Institutes of Health.