Can You Lose Fat While You Sleep?

America’s waistline is expanding. According to the National Institutes of Health, 2/3 of us—and nearly 20% of our children—are overweight or frankly obese. Obesity has become big business in the United States, and everyone—from the pharmaceutical companies to the fitness guru at the local gym—wants a piece of the adiposity pie. Health risks and economic impacts associated with the “obesity epidemic” are now frequent topics for news broadcasts, magazine articles, and even workplace discussions.

Obese people know they’re overweight. The majority of them have tried to shed those extra pounds, but they rarely seem to succeed, at least for the long haul. They’ve heard the same litany over and over: fast foods, overindulgence, sedentary living, and a lack of self-control are the underpinnings of their condition. They’re aching for something more helpful than the oft repeated eat-less-and-exercise-more advice; most of them have dabbled with unorthodox methods to lose weight. And a lot of them have heard commercials (and hoped they were true) for products that “burn calories while you sleep.” Alas, such advertisements are only designed to sell products with unproven benefits.

Oddly enough, though, there may be a nugget of truth to the sleep-obesity connection.

Recent studies have revealed that two hormones, leptin and grehlin, operate in a classic feedback loop to help control the human appetite. Leptin, which is produced by fat cells and released into the circulation, suppresses the appetite by influencing certain centers in the brain (specifically, the arcuate nucleus of the hypothalamus). Grehlin is secreted by specialized cells in the stomach, pancreas, and elsewhere; when it stimulates hypothalamic receptors, we become hungry. Normally, as one hormone rises, the other falls; this maintains a homeostatic balance between gluttony and starvation.

Interestingly, new research shows that insufficient sleep causes grehlin levels to increase, and likely suppresses leptin production. These hormonal shifts lead to an increase in appetite and a tendency to store fat. Furthermore, lack of sleep has been shown to inhibit the effects of insulin (a pancreatic hormone) on cellular membranes, thus decreasing cells’ abilities to metabolize fuels. In short, getting too little sleep can establish a hormonal pattern that contributes to weight gain.

Now, consider the following data from the National Sleep Foundation and a 2006 National Health Interview Survey: between 1985 and 2006, the percentage of adult Americans getting less than six hours of sleep each day increased significantly in all age groups (the NSF recommends seven to nine hours of sleep for adults). Surveys in adolescents show a similar pattern of sleep deprivation, particularly during those months when school is in session. Many Americans feel that insufficient sleep is part of their routine.

So, while it appears that certain overweight individuals—and anyone hoping to avoid obesity—can possibly benefit from lifestyle changes that ensure adequate sleep, intriguing questions surface in regards to the global issue of obesity in the United States:

  • Have the demands of our culture—in conjunction with the ease with which we can all reach for our next meal—created a trap that is snaring more and more victims?
  • Could we better address the problem of obesity in our society by imposing fundamental changes on all citizens’ lifestyles?
  • Would shorter workdays, nap breaks, telecommuting, or later school schedules have measurable effects on America’s obesity problem?

The answers are conjectural. But, rather than complain about the unfairness of being squeezed beside an obese individual the next time we’re on a plane or bus, it might be better to just sleep on it.