Your Junk-Food Cravings: Solved!

What’ll it be: Carrots or carrot cake? The answer may depend on how hungry your brain is, suggests a new study published in the Journal of Clinical Investigation.

Researchers manipulated participants’ glucose levels, and then showed them pictures of non-food items, low-calorie food (such as salad), and high-calorie food (like French fries). The participants rated their desire for each photo on a scale from 1 to 9, with a rating of 1 indicating "not at all" and a rating of 9 indicating "very much." When glucose levels dropped below normal, people were more likely to rate the high-calorie food photos higher.

Brain imaging scans showed that the area of your brain involved with reward is activated when your glucose levels drop, signaling your body to go out and find food. At the same time, the part of the brain that controls emotions and desires turns off. “Your body needs to feed itself, but the prefrontal cortex loses the ability to put on the brakes,” explains study author Rajita Sinha, Ph.D. “If this happens, you have little ability to control yourself when looking at high-calorie food, even if you know you should eat broccoli instead.”

More from MensHealth.com: The Deadly Truth About Diabetes

Even when blood glucose levels drop slightly—which can happen after only a couple hours of eating a meal—your prefrontal cortex will deactivate and desire high-calorie food, explains Sinha. And in obese individuals, the results were even more dramatic, she found.

But don’t worry: There are ways to keep your glucose levels up so you don’t fill your cart with Twinkies and Klondike bars. Eat healthy snacks throughout the day, sneak fiber into your meals so you stay fuller longer, or make yourself a preworkout snack so you're not tempted to hit up the drive-through after a hard sweat session.

1. Prev:The Waist-Shrinking Power of Guys’ Night
2. Next:Sleep Deprivation Makes You Fat