Researchers have some new weight-loss advice that's sure to be welcome news: Sleep can be just as important to a successful diet as healthful eating and exercise.
"Chronic sleep restriction is pervasive in modern societies, and there is robust evidence supporting the role of reduced sleep as contributing to the current obesity epidemic," write a pair of obesity experts in the new edition of the Canadian Medical Association Journal.
That evidence includes findings that overtired brains prompt people to eat more, and that some hormones that regulate appetite and metabolism don't work properly in people who don't get enough sleep.
The authors of the CMAJ commentary cite an experiment reported in Annals of Internal Medicine in 2010. Two groups of overweight adults were put on a diet that forced them to cut 680 calories per day. In addition, one group slept for 8.5 hours per night and the other slept only 5.5 hours per night. After two weeks, study volunteers in the sleep-deprived group had lost 55 percent less body fat than their well-rested counterparts. They had also lost 60 percent more lean body mass. The researchers concluded that when the body is tired, holding on to fat becomes a priority.
The commentary authors conducted their own investigation with 123 dieting adults. After 17 weeks, sleep habits were able to predict the amount of fat loss, they wrote.
In another study, the pair tracked the link between weight and sleep in adults over six years. At the end of the study, people who got seven to eight hours of sleep per night gained 5 pounds fewer than people who slept fewer than six hours per night.
"Sleep should be included as part of the lifestyle package that traditionally has focused on diet and physical activity," they conclude.