This Is Why Lack of Sleep Makes You Crave Junk Food (It’s Not for Energy)

Updated: May 08, 2017

There’s a reason doughnuts smell like heaven after you’ve had only four hours of sleep.

Syda-Productions/ShutterstockSleep has been a hot topic over the past few years, and with good reason: According to the National Institute of Health, more than one-third of adults don’t get the recommended 7 to 8 hours of sleep per night, and evidence shows that even children and adolescents sleep less than needed. Most people already know that not getting enough sleep has all types of horrible side effects like puffy eyes, memory loss, and overall grogginess, but what if sleep deprivation is also the reason you reach for a slice of pizza instead of a kale salad?

While it’s been previously thought that the body craves unhealthy snacks for a quick burst of energy to stay awake and alert when your body is tired, new research presented at the Cognitive Neuroscience Society’s annual meeting in San Francisco shows that sleep deprivation actually increases the brain’s sensitivity to food smells. A preliminary study conducted by Northwestern University’s Feinberg School of Medicine in Chicago explains that participants who slept only four hours showed greater brain activity in response to food smells, like potato chips and doughnuts, compared to when they’d slept a full eight hours.

“When tired, participants showed greater brain activity in two areas involved in olfaction—the piriform cortex and the orbitofrontal cortex—in response to food smells than they did when well rested. That spike wasn’t seen in response to nonfood odors,” study coauthor Surabhi Bhutani told Science News.

While this line of research is still ongoing, it’s pretty clear that sleep deprivation leads to extra calorie consumption and weight gain. So time you’re running on a few hours of sleep (it’s not recommended), outsmart the tricks you know your brain is playing on you and make a conscious decision to eat the healthier option. Whatever you do, avoid the foods that wreck your sleep.

If you’re having a hard time getting shut-eye every night, follow these 13 secrets to better sleep that doctors want you to know.