If you are thinking about going on a diet, you might want to plan an earlier bedtime too.
Researchers at the University of Chicago found that dieters who were well rested lost more fat—56% of their weight loss—than those who were sleep deprived, who lost more muscle mass. (They shed similar amounts of total weight regardless of sleep.)
Dieters in the study also felt more hungry when they got less sleep.
"Sleep and metabolism are controlled by the same sectors of the brain," Dr. Rapoport says. "When you are sleepy, certain hormones go up in your blood, and those same hormones drive appetite."