July 24, 2006

Want to lose weight? Try sleeping more

ANN ARBOR, Mich.—If you want to lose weight, get more sleep.

In a new article appearing in the current issue of Obesity Reviews, University of Michigan researcher Michael Sivak presents calculations showing that replacing one hour of inactive wakefulness—such as watching television—with sleep can result in a 6 percent reduction in caloric intake.

"Caloric consumption in a society with readily available food is likely to be approximately proportional to the number of hours of being awake," said Sivak, head of the Human Factors Division at the U-M Transportation Research Institute. "By replacing one hour of being awake with sleeping, we forgo a significant consumption of food because of the resulting reduction in the opportunity to eat."

Sivak says that a person who sleeps seven hours a night and consumes 2,500 calories during the remaining 17 hours of the day can cut 147 calories by simply sleeping an extra hour instead of watching TV. He calculated that such a decrease in caloric intake would result in a body-weight reduction of about 14 pounds per year.

"Recent research has suggested that the levels of the hormones leptin and ghrelin mediate an association between lack of sleep and weight gain. But this may turn out to be only part of the story," he said. "The behavioral, non-hormonal relationship between sleep and weight is another possible connection.

"To the extent that a large proportion of the population is both overweight and voluntarily sleep-deprived, replacing some sedentary activity with sleeping might offer a practical behavioral solution for a large segment of the overweight population."

Contact: Bernie DeGroat
Phone: (734) 936-1015 or 647-1847