Does too little sleep lead to weight gain?

Study doesn't prove that sleeplessness causes people to gain extra weight, they do show that sleep should be priority.

NEW YORK: Want to avoid weight gain? Maybe some more sleep would help.

People who got very little sleep ate more but didn't burn any extra calories, according to a U.S. study in the American Journal of Clinical Nutrition that adds to evidence supporting a link between sleep deprivation and weight gain.

Approximately 50 to 70 million U.S. residents – including a significant number of shift workers – suffer from chronic sleep loss and sleep disorders, according to the National Institutes of Health.

"If you're trying to control your weight, it would be helpful not to be sleep-deprived," said Marie-Pierre St-Onge of the New York Obesity Research Center at St. Luke's-Roosevelt Hospital, who led the study.

Although the most recent study, like other that have gone before, doesn't prove that sleeplessness causes people to pack on the extra weight, they do show that sleep should be a priority, experts said.

St-Onge and her colleagues recruited 30 men and women in their 30s and 40s, all of roughly normal weight. The participants lived and slept in a research center during two different five-night periods.

During one of those visits, they were allowed to sleep for nine hours each night. During the other, they were only allowed four hours of shut-eye. Both times, they were fed a strict diet for the first four days of their stay and then were allowed to eat whatever they wanted on the fifth and final full day.

Tests showed that regardless of which sleep schedule they were on, people burned a similar amount of calories, about 2,600 per day.

But when they were sleep-deprived, they fed themselves about 300 more calories on average on the final day of the study compared to when they had been sleeping normally. Well-rested participants ate an average of 2,500 calories that day, compared to 2,800 when they were running on less sleep.

If that kept up in a person's normal daily life, it would put the sleep-deprived at a higher risk of obesity, the authors said.

Participants also said they felt more sluggish and less energetic after a few days on the short sleep schedule.

There are a few possible explanations behind the link between sleep and eating, with previous studies having shown that sleep-deprived people burn fewer calories.

One is that sleep "seems to play a role in how your body manages the hormones that control how hungry you are, when you're hungry (and) what kinds of foods you're hungry for," said Michael Grandner, who studies sleep and sleep disorders at the University of Pennsylvania in Philadelphia.

Another explanation is that when people are tired, they may be less good at making healthy eating decisions.

"It's possible that when you're on short sleep you're more susceptible to giving in to your desires," St-Onge told Reuters Health.

"You walk past a (food) cart or bakery and it smells so good. If you're sleep-deprived, you may be like, 'oh, what the heck.'"

Grandner added that it's possible the link goes both ways, and that eating too much of certain kinds of foods can disrupt a person's sleep schedule, or that somebody with a stressful job may sleep too little and also eat too much as a result.

Too little sleep has also been tied to a host of other health problems, including heart disease and diabetes, which have their own associations with weight, complicating the picture even further, he added.