A new study confirms that not getting enough sleep at night can lead to weight gain.
The startling but perhaps not too surprising results of a study at the University of Colorado showed that people
deprived of sufficient sleep gained nearly 2 pounds in one week.
The reason? People eat more when they are tired.
The study, performed in collaboration with the CU Anschutz Medical Campus, suggests that sufficient sleep could help battle the obesity epidemic.
“I don’t think extra sleep by itself is going to lead to weight loss,” said Kenneth Wright, director of CU-Boulder’s Sleep and Chronobiology Laboratory, which led the study.
The findings were presented this month at the Proceedings of the National Academy of Sciences.
Previous research has shown that a lack of sleep can lead to weight gain, but the reasons for extra pounds were unclear. In the new study, published March. 11 the researchers show that, while staying awake longer requires more energy, the amount of food study participants ate more than offset the extra calories burned.
“Just getting less sleep, by itself, is not going to lead to weight gain,” Wright said. “But when people get insufficient sleep, it leads them to eat more than they actually need.”
The study used 16 young, lean adults to test their hypothesis at the University of Colorado’s sleep center for two weeks.
All participants spent the first three days with the opportunity to sleep nine hours a night and eating meals that were controlled to give participants only the calories they needed to maintain their weight in order to establish baseline measurements.
But after the first few days, the participants were split into two groups: one that spent five days with only five hours to sleep in and one that spent five days with nine hours of sleep opportunity.
In both groups, participants were offered larger meals and had access to snack options throughout the day ranging from fruit and yogurt to ice cream and potato chips. After the five-day period, the groups switched.
On average, the participants who slept for up to five hours a night burned 5 percent more energy than those who slept up to nine hours a night, but they consumed 6 percent more calories.
Those getting less sleep also tended to eat smaller breakfasts but binge on after-dinner snacks. In fact, the total amount of calories consumed in evening snacks was larger than the calories that made up any individual meal.
The current findings add to the growing body of evidence showing that overeating at night may contribute to weight gain, say the researchers.
