Sleeping longer can help cut calorie intake – study
Getting an hour or so more sleep each night can help people to cut calories, according a small clinical trial in overweight adults.
Researchers in the US found that people who typically slept for less than 6.5 hours a night shed an average of 270 calories from their daily intake when they got an extra 1.2 hours of sleep.
Sustained over three years, the reduction in calories could lead people to lose about 12kg (26lbs) without changing their diet during the day, the scientists believe. Some participants in the study consumed 500 fewer calories a day after improving their sleep.
The study was not designed to look at weight loss, but researchers noticed the fall in calories within two weeks of patients changing their sleep patterns.
“If healthy sleep habits are maintained over longer duration, this would lead to clinically important weight loss over time,” said Dr Esra Tasali, of the University of Chicago’s sleep centre. “Many people are working hard to find ways to decrease their caloric intake to lose weight – well, just by sleeping more, you may be able to reduce it substantially.”
The trial studied 80 adults aged 21 to 40 with a body mass index between 25 and 29.9, meaning they were overweight. Half of the participants were randomly assigned to receive personalised sleep hygiene counselling aimed at extending the amount of time they slept each night.
The study did not ask the volunteers to restrict their diets or change their exercise routines. All slept in their own beds and used wearable devices to track their sleep duration.
Previous studies have shown that getting too little sleep can lead people to put on weight by increasing their food intake. The latest trial, published in Jama Internal Medicine, suggests the effects may be reversed by helping people to sleep for longer.
“Most other studies on this topic in labs are short-lived, for a couple of days, and food intake is measured by how much participants consume from an offered diet,” said Tasali. “In our study we only manipulated sleep and had the participants eat whatever they wanted, with no food logging or anything else to track their nutrition by themselves.”
One of the most surprising findings from the study is that a single sleep counselling session could change people’s bedtime habits enough to improve the amount of sleep they got. “We simply coached each individual on good sleep hygiene, and discussed their own personal sleep environments, providing tailored advice on changes they could make to improve their sleep duration,” Tasali said.