If you're concerned about your weight and trying to shed a few pounds, you would be well advised to get a good night's rest.
That's the take-home message from a study by researchers at Mayo Clinic in Rochester, Minn. They found people eat more when they're sleep-deprived.
The new report builds on earlier observational studies of the general population that suggest people who suffer from chronic sleep problems are prone to weight gain.
But in this case, the Mayo Clinic researchers studied 17 healthy young men and women in a carefully controlled laboratory setting, hoping to obtain a better understanding of the effects of sleep on food consumption.
For three days, the volunteers were closely monitored to determine how much they normally eat and sleep. Then they were randomly divided into two groups for eight more days of testing.
About half of them were allowed to maintain their regular sleep habits. But the other half had their sleep cut back to two-thirds of their normal shut-eye. During the study, all the volunteers were allowed to eat whatever they wanted.
The study revealed a reduction in sleep led to a significant increase in the amount of food eaten. The volunteers in the sleep-restricted group consumed an average of 549 additional calories on the days after their sleep was curbed, compared to when they got their normal night's rest.
And despite being awake longer, they didn't burn a lot more energy with extra activities. So the additional calories could potentially cause a person to put on pounds over time.
"If what we found over eight days occurs in somebody repeatedly and the effects last for many days, this could indeed be a powerful force driving somebody to gain weight," said Andrew Calvin, a co-author of the study, which was presented this week in San Diego at a meeting of the American Heart Association.
Active males in their 20s typically need up to 3,000 calories per day, and females of similar age and activity level require about 2,350 calories. "The 549 extra calories could add up to a pound of fat in less than a week should no compensation occur [in terms of increased exercise]" said Dr. Calvin.
The researchers aren't sure why a lack of sleep causes people to eat more. And they acknowledge the results need to be confirmed with a much larger study lasting a long period of time.
Even so, Dr. Calvin said the common problem of people not getting enough sleep could be contributing to rising obesity rates in many countries around the world.
"I think we are really in the middle of two epidemics. The first is the obesity epidemic. The second is the sleep-deprivation epidemic," he said. And if Dr. Calvin's hunch is correct, these two epidemics could be more closely linked than previously imagined.