Study links lack of sleep to unhealthy snack cravings

Evanston, IL — Restless and hankering for the nearest junk food but not sure why? A recent study purportedly “nose” the answer.

Researchers at Northwestern University’s Feinberg School of Medicine suggest that the brain may show different responses to food odors when it’s sleep-deprived, helping explain some people’s cravings for not-so-nutritious sustenance when they’re tired.

For the study, the researchers divided 25 men and women ages 18 to 40 into two groups. Participants in one group got eight hours of sleep on one night before being limited to four hours of sleep on a night four weeks later. The order of these nights was reversed for the second group.

During the day after each night of deprived or non-deprived sleep, the researchers served breakfast, lunch and dinner to the participants from a controlled menu, while also offering a snack buffet that included calorie-dense foods such as cinnamon rolls, doughnut holes, chocolate chip cookies, pizza bites and potato chips. The researchers monitored the quantity and type of food consumed.

Participants who were sleep-deprived ate more calorie-dense foods while exhibiting more activity in the piriform cortex – the part of the brain that receives input from the nose. The piriform cortex typically transmits information to the brain’s insular cortex, including signals for smell, taste and volume of food in the stomach, but these connections were reduced among the participants who had less sleep.

“When you’re sleep-deprived, these brain areas may not be getting enough information, and you’re overcompensating by choosing food with a richer energy signal,” Thorsten Kahnt, study senior author and assistant professor of neurology at NU, said in an Oct. 8 press release. “But it may also be that these other areas fail to keep tabs on the sharpened signals in the olfactory cortex. That could also lead to choosing doughnuts and potato chips.”

The study was published online Oct. 8 in eLife.