Lack of Sleep May Make You Fat

Lack of sleep may make you fat
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Too little sleep could result in too much of something else: weight. A new study from Mayo Clinic researchers found that a lack of sleep can make you fat. And no, it’s apparently not because people who sleep less are too tired to exercise.

Sleep deprived people eat more

This latest study, which was presented at the American Heart Association’s Epidemiology and Prevention/Nutrition, Physical Activity and Metabolism 2012 Scientific Sessions, explored two major health issues: lack of sleep or sleep deprivation, which affects 28% of adults in the United States; and overweight and obesity, which has reached epidemic proportions at around 66% of the adult population.

The study group included 17 healthy young men and women who were evaluated for eight nights. Half of the subjects slept their normal amount of hours and half slept only two-thirds of their normal sleeping time. All of the participants were allowed to eat as much as they wanted during the study.

According to the researchers, their findings included the following:

  • Study participants who were sleep deprived (those who slept 80 minutes less than controls) consumed an average of 549 additional calories per day
  • The amount of energy exerted by participants in the sleep deprived group did not differ significantly from that exerted by controls, which indicated that those who got little sleep did not burn additional calories
  • Too little sleep was associated with higher levels of leptin, a hormone that has been called an obesity hormone. Leptin is produced in fat cells, circulates in the bloodstream, and travels to the brain. The hormone plays a key role in signaling the brain when people should stop eating.
  • Lack of sleep was also associated with declining levels of ghrelin, another hormone associated with obesity. Ghrelin stimulates the brain to increase appetite and the accumulation of lipids in fatty tissue.

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Earlier research on sleep and weight
According to research results presented at the 23rd Annual Meeting of the Associated Professional Sleep Societies in June 2009, study participants who were sleep deprived said they had less of an appetite, a decline in food cravings, and ate less, but they still gained weight. The sleep study was conducted in a laboratory setting.

During the 11-day study, the researchers reported that the 92 participants whose sleep was restricted gained an average of nearly 3 pounds (1.31 kilograms). Of the participants who slept less and who said their appetite and food consumption had changed, more than 70% said both had decreased by day 5 of the study. The nine controls who got an adequate amount of sleep did not experience weight gain.

In this study, the lead investigator Siobhan Banks, PhD, a research fellow at the University of South Australia, noted that even though the physical desire to eat did not increase among the participants deprived of sleep, other factors such as the sedentary setting of the lab and the ability to snack for a longer time might have had an impact on weight gain.

In the Mayo Clinic study, the researchers determined that the changes in leptin and ghrelin levels they observed were likely a consequence, and not a cause, of overeating. They also noted that although their findings suggest too little sleep may make you fat, their results need to be verified in future studies in more real-life situations, like home environments.

SOURCES:
American Heart Association
Banks S et al. Sustained sleep restriction in healthy adults with ad libitum access to food results in weight gain without increased appetite or food cravings.

Image: Courtesy Wikimedia Commons

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