Less sleep leads to more eatingSleeping a mere five hours a night during a workweek with unlimited access to snacks isn’t good for your waistline.

A new study led by the University of Colorado at Boulder found that participants gained about 1 kg when put in such a situation.

Published in the Proceedings of the National Academy of Sciences, the newest findings show that, while staying awake longer did indeed require more energy, the extra calories burned were more than offset by the amount of food the study participants consumed.

“Just getting less sleep, by itself, is not going to lead to weight gain,” said Kenneth Wright, director of CU-Boulder’s Sleep and Chronobiology Laboratory that lead the study. “But when people get insufficient sleep, it leads them to eat more than they actually need.”

The researchers monitored 16 young, lean and healthy men and women who lived for two weeks at the University of Colorado Hospital, which has a “sleep suite.”

On average, those who slept for up to five hours a night burned five percent more energy than those who snoozed up to nine hours. However, those with less shut-eye also consumed six percent more calories.

Those getting less rest tended to eat smaller breakfasts but binged on after-dinner snacks, according to the researchers.

In fact, the late-night food intake totaled more in calories than individual meals, they said.

The authors of the study also found that men and women responded differently to having access to unrestricted amounts of food.

While both males and females put on weight when only allowed to sleep five hours, men gained even with “adequate” rest when they could eat as much as they desired. Women, however, maintained their weight when they had “adequate” sleep, no matter how much food was at their disposal.

Lack of adequate shut-eye had already been linked to conditions from heart disease and cognitive impairment to obesity.