Getting a better night’s sleep may help you cut down on calories, a new trial this week has shown. The randomised, controlled study found that overweight people who often underslept consumed fewer calories over a two-week period after undergoing a course of sleep training. The findings suggest that a healthy sleep pattern should be a key part of any weight loss or obesity prevention program, the researchers say.
Sleeping at least seven hours a night, for most adults, is important to overall physical and mental health. Poor sleep can also muck with our metabolism, including the disruption of hormone levels that could predispose us to overeating. Sleep deprivation has been linked to obesity (defined as having a body mass index over 30) and other related conditions, such as type 2 diabetes.
Many doctors and health organisations already stress the connection between sleep and weight. But while good sleep may keep our appetite steady, it’s less clear whether helping people sleep more actually has an effect on their weight. The new research, published this week in JAMA Internal Medicine, seems to be one of the first randomised and controlled studies to test this hypothesis.
The researchers recruited 80 volunteers who were overweight (defined as a BMI between 25 and 30) and who reported often getting under 6.5 hours of sleep a night. After a two-week session of getting their usual sleep, these volunteers were sorted in two groups, with the active group being counseled on ways to extend their resting hours. Over the next two weeks, both groups had their sleep, daily caloric intake, and total energy use measured (the volunteers also regularly weighed themselves but were never told their weight to prevent any subtle influence on their behaviour).
By the end of the trial, the volunteers in the active group got an average of 1.2 hours more sleep a night. They also ate about 270 fewer calories on average, lost about two pounds more than the control group, and dropped roughly a pound from their baseline weight. Interestingly enough, both groups still expended the same amount of daily energy during the trial, meaning the differences likely came from the fewer calories they ate while sleeping more.
“To our knowledge, this study provides the first evidence of the beneficial effects of extending sleep to a healthy duration on objectively assessed energy intake and body weight in participants who continued to live in their home environment,” the authors wrote.
Though the trial found only a small effect on people’s weight during the two-week period, the authors estimate that, if the same average reduction of caloric intake tied to good sleep were sustained, people would have lost up to 24 pounds over the course of three years. Of course, that’s easier said than done, since both sleep and weight are linked to many factors outside our total control, including the jobs we have, the neighbourhoods we live in, and our inherent biology.
Nevertheless, the researchers say that these findings only further demonstrate the importance of sleep. They recommend that “along with a healthy diet and regular physical activity, healthy sleep habits should be integrated into public messages to help reduce the risk of obesity and related comorbidities.”
Editor’s Note: Release dates within this article are based in the U.S., but will be updated with local Australian dates as soon as we know more.