Why We Crave Junk Food After a Bad Night's Sleep

It's not always easy to eat healthy. It's really not easy to eat healthy when you are sleep deprived.

If you've ever noticed that you're more likely to beeline to the pizza shop or your candy drawer when you're tired, you're not alone. While the phenomenon is quite common, you may have wondered why, exactly, that is. In a recent article for CNN, behavioral neuroscientist Erin Hanlon of the University of Chicago, who looks at the relationship between brain systems and behavior, put it in simple terms, "When you're sleep deprived, you're not like, 'Oh, you know what, I want some carrots...You're craving sweets and salty and starchy things." Fried food, ice cream, chips, and candy never looks better than when you're running on empty.

Hanlon also attributes our penchant for junk food when we're tired to evolution, since back in our hunter-gatherer days we couldn't have food around the clock and exhaustion sparked a desire to eat indulgent foods to satiate ourselves. These days, when hunger calls, dinner is as easy as clicking a few buttons online or putting something in the microwave, but our brains have not evolved at the same rate as the surplus of omnipresent food availability.

Scientific studies on hormones that control hunger (among other functions) also show that exhaustion and being hungry often accompany each other. "When you're sleep deprived, research shows, ghrelin levels spike while leptin takes a nose dive. The result is an increase in hunger," explains the article's author, Sandee LaMotte.

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If you're struggling after a night of tossing and turning, consider taking a brisk walk outdoors or going to the gym before you reach for junk food. It may not completely erase your cravings, but you may find you feel more energized and less likely to overeat after adding some movement into your day.

What's your best tip for avoiding junk food when you didn't sleep well the night before?