A study showed that there is a significant link between inadequate sleep and weight gain. The results explained that women who got only five hours of sleep a night, on average, gained substantially more weight than those who had seven. women who got seven hours or more of sleep actually ate more than those who got five hours' sleep. And the exercise habits were about the same, too -- although the group that slept a healthier seven hours tended to exercise a little more.

The women were part of the Nurses Health Study, which followed more than 68,000 women for 16 years. They were asked to report their weight and lifestyle regimen every two years. By the end of the study, women who slept five hours a night were 32 percent more likely to experience major weight gain -- defined as an increase of 33 pounds or more -- and 15 percent more likely to become obese, compared with women who slept seven hours.

There are several possible explanations for the findings. It could be that sleep deprivation causes the body to metabolize calories less efficiently. Or it may be that the actual forms of exercise or the exact patterns of eating differed between the two groups of women in the study.
One intriguing area of research has suggested that sleep disturbances, such as deep snoring and night-time awakenings, may affect weight, perhaps due to a subtle inherited trait that shows increasing impact with age.