Adding an hour or so of sleep every night could help people reduce their daily calorie intake by 270 calories, a new study has found.
Researchers from the University of Chicago carried out a clinical trial with 80 adults to examine how sleep interacts with obesity, and found that getting more sleep could lead to a weight loss of 26lb (approximately 11kg) over a period of three years.
The study, published in the journal Jama Internal Medicine, found that young, overweight adults who habitually slept fewer than 6.5 hours a night were able to add an extra 1.2 hours of sleep per night after undergoing counselling to improve their sleeping habits.
Getting the extra sleep reduced people’s daily overall intake by an average of 270 calories per day, the results showed.
Some people were consuming as much as 500 fewer calories just by sleeping more.
Dr Esra Tasali, from the University of Chicago’s sleep centre, said the original goal of the study was not to look at weight loss.
“But even within just two weeks, we have quantified evidence showing a decrease in caloric intake and negative energy balance – caloric intake is less than calories burned,” she said.
“If healthy sleep habits are maintained over longer duration this would lead to clinically important weight loss over time.
“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.”
According to the researchers, the study did not attempt to restrict the diets of the participants.
Instead, they slept in their own beds and tracked their sleep with wearable devices. Study participants followed an otherwise normal lifestyle without any instructions on diet or exercise.
Dr Tasali said that most other studies in this area are “short-lived” and only last “a couple of days”.
She added that the participants’ food intake is usually measured by how much they consume from an “offered diet”.
“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,” she said.
The researchers used a clinically-proven, urine-based test to look at changes in people’s energy stores to track how many calories people were consuming.
The method involves a person drinking water in which both the hydrogen and oxygen atoms have been replaced with less common, but naturally occurring, stable isotopes that are easy to trace.
Bedtime habits that were improved through the counselling included limiting the use of devices, such as mobile phones, before going to sleep.
Dr Tasali said that doing this helped people get more sleep.
“We saw that after just a single sleep counselling session, participants could change their bedtime habits enough to lead an increase in sleep duration,” she added.
“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.”
Additional reporting by PA
