Sleep, Weight Gain & Obesity

A large Japanese study examined the relationship between sleep duration, weight gain and obesity. The results were published this month in the journal Sleep.

The study involved 35,247 employees of an electric power company in Japan. They were evaluated at an annual health checkup in 2006 and 2007. Usual sleep duration was self-reported.

Typically obesity in adults is defined as having a body mass index (BMI) of 30 or higher. But in this study a BMI of 25 or higher was considered to be obese. This criterion has been proposed for Asia-Pacific populations.

Results show that about 36 percent of men and 12.5 percent of women were obese. About six percent of the non-obese men were obese at the one-year follow-up.

Short sleep duration was associated with both weight gain and the development of obesity in men. The men who reported sleeping less than five hours per night were 91 percent more likely to develop obesity than men who slept seven to less than eight hours. Men who slept five to less than six hours per night were 50 percent more likely to become obese.

“I believe the data are currently compelling enough to recommend good diet, adequate exercise, AND adequate sleep in people trying to lose weight,” wrote Dr. Najib Ayas in a commentary on the study.

Sleep and weight are interconnected in a variety of ways. A recent study suggested that short sleep may lead to weight gain by reducing exercise. And eating when you should be sleeping may lead to weight gain.

Adequate sleep may be associated with more healthful food choices. But short sleep may cause you to crave more high-calorie, high-carb foods. And it may affect the levels of the appetite-regulating hormones leptin and ghrelin.

Read more about sleep and weight gain and sleep and obesity.

Image by chrisphoto