It sounds like one of those late night infomercials but researchers say that sleeping is a key component to avoiding obesity. Yes, sleep, sleep, sleep those pounds away. Two studies published yesterday found that subjects who failed to get enough sleep had higher levels of a hormone that makes you feel hungry and lower levels of a hormone that tells you that you're full.

North American Association for the Study of Obesity found that those who got less than four hours of sleep were 73 percent more likely to be obese than those who slept seven to nine hours per night. They study followed the lives of approximately 18,000 adults.

The second study by Stanford University and the University of Wisconsin studied hormone levels and found that those who sleep five hours had nearly a 15 percent increase in ghrelin, a hormone that increases appetite. There was also a 15.5 percent decrease in the hormone leptin which makes you feel full. The study found these results to be consistent regardless of the body mass, gender, eating and exercise habits.

'We strongly recommend that any weight-reduction program include getting enough sleep as one of their tips,' said Dr. Esra Tasali, co-author of one of the new studies.

One problem Americans face is a lack of sleep. Ideally, the study found that 7.7 hours of sleep per night gives the best hormone balance.

'Additional studies should examine the possible role of chronic sleep curtailment as a previously unrecognized risk factor for obesity,' one of the studies found.

So if you want to lose weight, don't forget to hit the sack early.