Obesity is epidemic, and has many causes. One of them is that the average nights' sleep has dropped from nine hours a night to six and three-quarters hours a night over the last hundred years, and sleep is responsible for many weight and appetite controlling hormones, such as growth hormone, leptin, phrelin and ghrelin. So can you really sleep your way to skinny? Many sleep studies suggest you can.
How much sleep is optimal for staying thin? Between seven and nine hours is best. Less than seven hours increases the risk of obesity approximately 30 percent and adds an extra five pounds on average.
According to Jean-Philippe Chaput, MSc, from Laval University in Quebec City, Quebec, Canada, and colleagues, current treatments for obesity have been largely unsuccessful in maintaining long-term weight loss, suggesting the need for new insight into the mechanisms that result in altered metabolism and behavior and may lead to obesity.
The increase in body weight in the U.S. population has been paralleled by a reduction in sleep times. For the past four decades, daily sleep duration has decreased by one and a half to two hours, and the proportion of young adults sleeping less than seven hours per night has more than doubled, from 15.6 percent in 1960 to 37.1 percent in 2002.
Studies in adults and children have repeatedly shown that reduced sleep is associated with increased weight.
To determine the relationship between sleep duration and weight, researchers followed 276 adults aged 21 to 64 who were enrolled in the Quebec Family Study, a six-year study in a community setting. The investigators compared weight gain relative to three categories of sleep duration ― short (5-6 hours), average (7-8 hours), and long (9-10 hours).
Compared with average-duration sleepers, short-duration sleepers gained 4.4 pounds more in a six year period. At six years, short-duration and long-duration sleepers were 35 percent and 25 percent more likely to experience a 12 pound weight gain, respectively, compared to those who slept seven to eight hours a night.
Compared with average-duration sleepers, short-duration sleepers had a 27 percent increased risk for the development of obesity, and long-duration sleepers had a 21 percent increase in risk. Adjustment for caloric intake and physical activity did not affect these connections.