The study included 17 healthy young men and women who were studied for eight nights. Half of the participants got their normal amount of sleep (control group) while the other half got only two-thirds of their typical amount of sleep (sleep-deprived group).
All the participants were allowed to eat as much as they wanted during the study.
Those in the sleep-deprived group slept one hour and 20 minutes less each night than those in the control group, and consumed an average of 549 additional calories per day.
Both groups burned about the same amount of energy for activity, which suggests that those in the sleep-deprived group didn't burn additional calories.
Lack of sleep was associated with increased levels of leptin and decreased levels of ghrelin, both of which are appetite-associated hormones. These changes were more likely a result of overeating, rather than the cause of overeating, according to the study, which was presented Wednesday at an American Heart Association (AHA) meeting.
"Sleep deprivation is a growing problem, with 28 percent of adults now reporting that they get six or fewer hours of sleep per night," study co-author Dr. Andrew Calvin, a cardiology fellow and assistant professor of medicine at the Mayo Clinic, said in an AHA news release.
Although this study suggests sleep deprivation may be an important and preventable cause of weight gain and obesity, it was a small study and does not prove a cause-and-effect relationship, the researchers noted.
"Larger studies of people in their home environments would help confirm our findings," Calvin said.
Because this study was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.