More sleep could lead to weight loss, a new study reports, finding that people who slept more reduced their daily calorie intake.
The University of Chicago study centred on the effect of increased sleep in overweight people who slept less than 6.5 hours a night.
Results showed participants who slept more reduced their calorie intake by 270 calories a day.
Continued over a year – and without changing diet or exercise habits – that would lead to an almost 9lb (4kg) weight loss and a whopping 26lb (12kg) loss over three years, the study predicted.
“If sleep is extended over longer periods, weight loss in the form of fat mass would likely increase over time,” researchers stated.
“A few observations suggest that sleeping 7 to 8 hours per night is associated with greater success in weight loss interventions.”
The sleep and weight loss study was published in medical journal JAMA Internal Medicine on February 7.
How does sleep help weight loss?
Previous research already shows that insufficient sleep is a risk factor for obesity.
The study studied a group of 80 overweight people who slept less than 6.5 hours per night.
Participants weren’t asked to change their diet or exercise habits and even slept in their own beds.
One group was randomly selected to extend their sleep to eight and a half hours – and the other group carried on as usual.
Scientists found that participants were able to increase their sleep time by 1.2 hours (72 minutes) in the two-week period and reduced calorie intake by 270 calories per day.
Why would sleeping more reduce calorie intake?
The researchers said: “Evidence from laboratory sleep restriction studies suggests that increased hunger, alterations in appetite-regulating hormones, and changes in brain regions related to reward-seeking behaviour are potential mechanisms that promote overeating after sleep restriction.”
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In short, sleeping less increases hunger and overeating.
They concluded: “Improving and maintaining healthy sleep duration over longer periods could be part of obesity prevention and weight loss programs.”
Dr Esra Tasali from the University of Chicago’s sleep centre said the study wasn’t focussed on weight loss.
“But even within just two weeks, we have quantified evidence showing a decrease in caloric intake and a 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.”