Fewer than five hours of sleep a night coupled with access to high-calorie food can increase weight, according to a new study.

The present study was conducted by a study team led by researchers from the University of Colorado Boulder. Researchers say that getting sufficient sleep alone won't help people lose weight, but it could help people maintain a healthy weight.

"I don't think extra sleep by itself is going to lead to weight loss. Problems with weight gain and obesity are much more complex than that. But I think it could help. If we can incorporate healthy sleep into weight-loss and weight-maintenance programs, our findings suggest that it may assist people to obtain a healthier weight," said Kenneth Wright, director of CU-Boulder's Sleep and Chronobiology Laboratory. 

The study included 16 young and healthy adults. Note that the study was conducted in controlled lab settings that allowed researchers to monitor energy intake and use by the study participants.

The subjects were, for the first three days, allowed to sleep for nine hours a night and eat food that had just enough calories to maintain the weight of the subjects.

Next, all the participants were divided into two groups; one set of subjects had an opportunity to sleep for nine hours a night while the other could sleep for only five hours a night. Both groups had access to unlimited amount of food for five days, after which the groups were asked to switch sleep timings. 

The study results showed that though energy use was higher for the sleep-deprived group, with them spending 5 percent more energy than those who got nine hours of sleep a night, these people had higher intake of calories (6 percent more). The sleep-deprived group was also more likely to binge on snacks than the group that got enough sleep.

In the study, both men and women who got fewer hours of sleep had an increase in weight.

Over a quarter of all people living in the U.S. report having insufficient sleep, according to data from Centers for Disease Control and Prevention.

Lack of good sleep has been associated with a number of other chronic conditions like stroke and cancer. Previous research published in the journal Obesity, says that short sleep duration was found to be independently associated with weight gain among all age groups.  Another study published in American Journal of Epidemiology too links reduced sleep with modest weight gain in women.

A study published in the American Journal of Clinical Nutrition had found that shorter duration of sleep makes people eat more, especially food that is high in fat. When people do not get enough exercise to use this extra food, they tend to store it in their bodies.

The present study is published in the journal Proceedings of the National Academy of Sciences.