A Bizarre Side Effect of Too-Little Sleep

With all the demands of work and family and the very real need for some "I" time, it's hard to get enough sleep, especially on weekdays.

If that describes you, ask yourself this question: Do you crave fatty foods?

It turns out that our appetite for fatty foods--from cheeseburgers to cheesecake--is increased when we don't get enough sleep. Not only does this have implications for insomniacs, but also for those who work the evening shift, night shirt, rotating shifts or any kind of irregular schedule.

It's long been known that too-little sleep can lead to weight gain, but researchers from the Perelman School of Medicine at the University of Pennsylvania have figured out why. Not only do we consume more food after a night of total sleep deprivation, but also we eat more fat and less carbs. And we do it because the brain commands it.

The study: Led by Hengyi Rao, PhD, a research assistant professor of cognitive neuroimaging in neurology and psychiatry, the team recruited 46 healthy and mostly non-obese adults aged 21 to 50. None smoked and all said they typically slept between 6.5 and 8.5 hours a night. The entire group was sequestered in a sleep lab for five days and four nights with 24/7 monitoring.

The participants were given one night of regular sleep and were then randomized for either total sleep deprivation (34 volunteers) or as part of the control group (12 volunteers) for the remaining three nights. Those who stayed awake all night were allowed to move about, watch TV, read, play video and board games and eat as much or as little as they wanted. Each was given a brain scan, known as a functional MRI (fMRI), to examine brain connectivity changes.

The results:

  • Those who were not allowed to sleep consumed almost 1,000 calories while they stayed awake all night. In addition, they ate a similar amount of calories during the day following sleep deprivation as they did the day before.

  • What did they eat? It wasn't celery and carrots. These healthy adults ate a greater percentage of calories from fat and a lower percentage of calories from carbohydrates during the day following total sleep deprivation.

  • Notably, the researchers found from the brain scans that those who were sleep deprived and craving fatty foods had an increased connectivity with the part of the brain called the "salience network," which is a pathway in the brain that guides decision-making.

The study findings were published in the journal Scientific Reports.

--From the Editors at Netscape

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