Have you ever had one of those nights where you stay up late and then can't think about eating anything other than pizza and doughnuts? Well, if you've ever wondered why we crave the greasiest, sweetest, unhealthiest foods when we're sleep-deprived, there seems to be a scientific explanation.
A new study by Northwestern Medicine has an answer for why we choose unhealthy food after having a night of little sleep. The study says our nose, or olfactory system, is to blame. The olfactory system is affected by a lack of sleep in two ways. First, your nose goes into "hyperdrive" as it tries to differentiate between food and non-food odors. Then, there is a communication breakdown with other areas of the brain that handle the food signals.
"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," says Thorsten Kahnt, assistant professor of neurology at Northwestern University. "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."
Sleep deprivation can also increase endocannabinoids, which affect how the brain responds to odors. Researchers also found that activity in the piriform cortex, a part of the brain that receives information from the nose, differed between food and non-food odors when someone was tired.
"Our findings suggest that sleep deprivation makes our brain more susceptible to enticing food smells, so maybe it might be worth taking a detour to avoid your local doughnut shop next time you catch a 6 a.m. flight."
Maybe next time you're about to crawl out of bed in the middle of the night to grab an unhealthy snack, just try and fall back asleep instead. Science says your nose is too tired to know any better!