... how poor sleep can lead to weight gain ..

(extracted from shopping lifestyle)

They don't call it beauty sleep for nothing. Recent scientific studies show a strong relationship between sleep deprivation and weight gain. Here are some of the findings:

Research finding #1:

Women who slept 5 hours or less a night gained more weight than those who slept for at least 7 hours a day.

Research finding #2:

People who sleep 2 to 4 hours a night are 73 percent more likely to be obese than those who get seven to nine hours.

Research finding #3:

People who slept less than 6 hours a night experienced an increase in their body mass index (BMI) more than those who slept 7 to 8 hours.

Research finding #4:

People who slept less than 8 hours a day had larger increases in body fat than those who slept more.

How sleep affects our bodies

"Lack of sleep disrupts every physiologic function in the body," says Eve Van Cauter, Ph.D., of the University of Chicago. In fact, sleep loss has such an adverse effect on our ability to metabolize sugar, she says, that in one week of severe sleep deprivation (such as four hours per night), an otherwise healthy person will be in a pre-diabetic state.

"One of the more interesting ideas that has been smoldering and is now gaining momentum is the appreciation of the fact that sleep and sleep disruption do remarkable things to the body ?including possibly influencing our weight," agrees David Rapoport, MD, associate professor and director of the Sleep Medicine Program at the New York University School of Medicine in New York City.

The reason: Sleep loss can reduce our bodies' capacity to perform basic metabolic functions such as regulating blood-sugar levels, storing carbohydrates and regulating hormone secretion. All of these major activities get out of whack when we're sleep-deprived. Not surprisingly, the balance of appetite-regulating hormones go haywire too so our normal cues for eating are altered.

Sometimes, an undiagnosed medical illness might also cause poor sleep habits, say the sleep experts. Someone with an underactive thyroid gland, for instance, will feel fatigued and gain weight. And someone who suffers from sleep apnea will wake up repeatedly during the night.

How sleep affects eating

Sleep researchers have found that sleep deprivation (even a mild case of inadequate sleep) quickly disrupts normal levels of the appetite-regulating hormones: Increasing the levels of a hunger hormone (ghrelin) while decreasing levels of a hormone that makes you feel full (leptin). The effects can set the stage for overeating and weight gain.

"It's amazing how much people's sleep is reflected in the hormones in their blood," says Emmanuel Mignot, a Howard Hughes Medical Institute investigator at Stanford University. Sleep-deprived people, he believes, eat more because they're hungrier, they're awake longer and may be tempted by foods everywhere they go."When you're sleep-deprived, you may overeat well in excess of the caloric demands, and, therefore, sleep loss is probably also a risk factor for weight gain and obesity," warns Van Cauter.

This could explain why when we're feeling fatigued, we don't always make healthy food choices: We eat junk food as a pick-me-up during the day when we're feeling sleepy, fail to stick to our healthy eating plan, and snack right before bedtime.

The bottom line? Most experts agree that logging in an extra couple of hours of sleep each night isn't a bad idea, especially if you're trying to lose weight and if you get six hours of sleep of less a night. You may just discover that you aren't as hungry or you don't crave high-calorie foods anymore.