Late nights could make you fatter

Sleep it off

Having trouble fitting into your jeans?

You might want to spend a little more time in bed–because according to new research, even a few late nights could make you fatter. And fast.

For two weeks, a team of sleep researchers at the University of Colorado assigned 16 healthy men and women to two groups.

During the first week, half the subjects slept for nine hours a night, while the other half were allowed only five hours of shut eye. During the second week, the tables were turned.

The subjects’ sleep schedules, eating habits, and metabolism were strictly documented throughout. All with the goal of identifying the extent to which just one week of sleep deprivation can affect your body.

The researchers found that not getting enough sleep delivers an immediate boost to your metabolism. In fact, subjects in this study burned 111 more calories per day due to sleep deprivation.

But unfortunately, this apparent perk didn’t amount to anything good.

That’s because what subjects lacked in sleep they made up for in snacks–especially after dinner. In a classic case of one step forward, two steps back, sleep-deprived participants gained an average of two pounds just within the first week.

Not too surprising, considering these subjects ate six percent more food than their well-rested peers–much of it in the form of fattening carbohydrates. (Luckily, though these eating habits improved once subjects started sleeping more at night.)

This relatively small, brief study doesn’t tell us much about how chronic sleep deprivation affects obesity risk in the long run. But it does point to one simple way you can give your weight loss efforts a winning edge.

Get your eight hours, every single night.

“Impact of insufficient sleep on total daily energy expenditure, food intake, and weight gain.” Proc Natl Acad Sci U S A. 2013 Mar 11. [Epub ahead of print]