Trying to lose weight? Eating wisely and getting active are undoubtedly two of the most effective ways to slim down. But add adequate sleep to your weight loss regime, and you'll shed even more fat, say researchers.

According to a University of Chicago study published in the Annals of Internal Medicine, when dieters got a full night's sleep, they lost the same amount of weight as when they slept less, but more than half of the weight they lost was fat. For dieters who cut back on their sleep, only one-fourth of their weight loss came from fat.

Dieters without adequate zzs also felt hungrier -- that's because lack of sleep produced higher levels of ghrelin, a hormone that triggers hunger and reduces energy expenditure.

"If your goal is to lose fat, skipping sleep is like poking sticks in your bicycle wheels," explains study director Plamen Penev, MD, PhD, assistant professor of medicine at the University of Chicago. "One should not ignore the way they sleep when going on a diet. Obtaining adequate sleep may enhance the beneficial effects of a diet."

Sounds like a dream! But how much snooze is enough? 7 hours of sleep every night is ideal, say experts.