Lack of Sleep

Cutting-edge sleep researchers are learning that our round-the-clock schedules may impact our health in surprising ways. While scientists don't yet know why, studies continue to show that those who don't get enough deep restful sleep tend to gain weight.

Whether or not losing sleep makes you feel hungrier and eat more food (some do, some don't) something about losing sleep changes the metabolism. Faced with a sleep deficit, we metabolize more lean muscle and less fat. Even if we burn calories during exercise, we struggle to lose weight.

The result? According to one study, people put on three pounds in less than two weeks just by having their sleep interrupted. The results of sleep deprivation show up in as few as a couple nights without deep restful sleep. And BMI, the official measure of weight, increases steadily as the sleep deficit increases.

What you can do:
We all know what makes us lose sleep -- too much to do, too much coffee (or alcohol), too much late-night television or video gaming, a little too much "quality" time with our Blackberries. We can't control everything that wakes us up or takes away our sleep -- the crying baby can't be ignored -- but we can control many of them.

How much sleep do you need? The Centers for Disease Control and Prevention recommends 7-9 hours for adults, while some experts have said 6.5-7.5 may be closer to the ideal.