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Lack of sleep linked to eating more calories
If you don't get enough sleep, you could end up piling on the pounds say researchers
15th March 2012 - Most people need between six and nine hours of sleep a night, but being sleep deprived may make you eat more than usual, according to a new study.
US researchers compared people allowed to sleep as much as they wanted with those who slept just two-thirds of their normal time. Being deprived of sleep was linked to eating more calories.
The NHS says sleep problems affect around 30% of the UK population.
"When people were sleep deprived, they ate an extra 549 calories per day," says researcher Dr Andrew Calvin, a fellow in cardiovascular disease and assistant professor of medicine at the US Mayo Clinic.
That's more than a High Street double cheeseburger.
Over a week's time, that could add up to a pound of weight gain. However, Dr Calvin says, "we don't know how long this effect lasts". His study lasted eight days.
He's presenting the findings to the American Heart Association's Epidemiology and Prevention/ Nutrition, Physical Activity and Metabolism 2012 Scientific Sessions.
The research echoes previous studies finding that lack of sleep is linked with weight gain and obesity, both in adults and children.
The study was funded by the US National Institutes of Health, an obesity centre and the Mayo Clinic itself.
Sleep deprivation effects
Dr Calvin and his team studied 17 men and women, aged between 18 and 40. First, they ruled out sleep disorders by having participants spend a night in a sleep lab.
Next, the participants wore a wristwatch-sized device called an actigraph to track their sleep for three nights at home. The researchers evaluated how much time each person normally slept.
Next was the eight-day study in the sleep lab. Men and women were randomly assigned to sleep as much as they wanted or to sleep only two-thirds of their normal sleep time.
During the at-home phase, the average amount of sleep was 6.5 hours.
During the sleep lab phase, the sleep-deprived group averaged 5.2 hours a night. The other group continued to sleep about 6.5 hours a night.
Everyone had access to as much food as they wanted. Food intake was logged.
Sleep less, eat more
While the sleep-deprived group ate the extra 549 calories a day, the comparison group actually ate about 143 fewer calories daily than usual.
The researchers tracked how active each group was. "A lot of people assume if they are awake longer, they will move more and burn more calories," Dr Calvin tells us.
He found that wasn't the case. He didn't find much difference in activity expenditure between the sleep-deprived group and the group that slept as much as they wanted.
Sleep deprivation was linked with somewhat higher levels of leptin, the hormone that tells your brain you are full. It was linked to somewhat lower levels of ghrelin, the hormone that tells your brain you are hungry.