Posted Nov 22, 2010
FIGHTING the flab isn’t just down to what you eat, but also how you sleep, scientists have found.
Dieters who get a good night’s rest lose twice as much fat as those who scrimp on their time in bed.
Sleep deprivation also increases levels of hormones that cause feelings of hunger.
The scientists tracked the weight-loss of ten volunteers who each spent four weeks in laboratory conditions eating a calorie-reduced diet.
For the first two weeks, the volunteers had eight-and-a-half hours sleep a night. The second stint saw them given five-and-a- half hours a night.
The U.S. scientists found the volunteers had lost similar amounts of weight in each period – but the proportion of fat lost was far higher over the fortnight with good sleep. An average of just over 6lbs – around 3kg, or almost half a stone – was lost during each 14- day session. With good sleep, volunteers lost 3.1lbs of fat and 3.3lbs of fat-free body mass, mostly protein. In the short-sleep session, the loss was 1.3lbs and 5.3lbs respectively.
Study director Plamen Penev, assistant professor of medicine at the University of Chicago, said: ‘Cutting back on sleep appears to compromise efforts to lose fat through dieting.’ When sleep was restricted, the study found that dieters also produced higher levels of ghrelin, a hormone that triggers hunger.
The findings will be reported in the Annals of Internal Medicine.