Losing Weight While You Sleep

In fact, it is sleep. A 2004 study by researchers at Stanford University and the University of Wisconsin found that people who slept less had lower levels of the hormone leptin and higher levels of the hormone ghrelin. Leptin suppresses your appetite, making it easier for you to pass up that second piece of cake. Ghrelin, on the other hand, makes the cake irresistible.

The benefits of sleep go beyond hormone control. The fewer hours you doze, the more waking hours you have to spend overeating. And when you're sleep-deprived, it's harder to get motivated to exercise, says Helene Emsellem, M.D., director of the Center for Sleep and Wake Disorders in Chevy Chase, Maryland, and a spokeswoman for the National Sleep Foundation. "You have to be in a good mood and optimistic to diet," she says. "You can't take it on if you're irritable, edgy, and tired."

Not getting enough shut-eye? Try these strategies: 

Slow down before bed. Set aside a half hour to an hour of "transition time" for a warm bath, gentle yoga, or anything that puts your mind on pause.
Stick to a regular schedule. Aim for 7 to 9 hours of sleep each night, Dr. Emsellem says. Skip the rerun of Entourage and go to sleep when it's bedtime. That'll make it easier to wake up each day when the alarm goes off.
Use the 2-hour rule. When you do crawl into bed later than usual, don't stay up or sleep in more than 2 hours past normal.