There’s a reason you overindulge late at night.

By Real Simple
Updated May 06, 2015
young woman looking into refrigerator
Credit: Tetra Images/Getty Images

If you give in to a late-night craving, chances are you can’t stop at just one chip or half a cookie—you continue reaching for more…and more without ever feeling truly satisfied. Now, researchers at Brigham Young University have identified one possible reason: Our brains don’t seem to feel as rewarded by high-calorie food in the evening. The small study, published in Brain Imaging and Behavior, sheds some light on why so many of us are guilty of turning a midnight “snack” into basically a full-on meal.

The researchers invited 15 female participants to two study sessions—one in the morning and one in the evening. At each session, the women were shown images of low-calorie food—like fruits and vegetables—and high calorie food—like cookies and cakes. The researchers tracked their brain responses and saw a spike in brain activity after looking at high-calorie foods. That makes sense—a big chocolate chip cookie probably looks more appetizing than a carrot. But surprisingly, they saw a change between the morning and evening sessions. In the evenings, the brain activity spike was significantly lower. The researchers concluded that our brains don’t find the same high-calorie food as rewarding or satisfying at night, which is probably bad news for any diet.

"You might over-consume at night because food is not as rewarding, at least visually at that time of day," lead author Travis Masterson said in a statement. "It may not be as satisfying to eat at night so you eat more to try to get satisfied."

Unfortunately, researchers don’t have a magic trick to make your brain feel more satisfied, nor do they have a formula to make fruits and vegetables more appealing than potato chips. But knowledge can, at the very least, be power—here’s the strategy Masterson tries: “I tell myself, this isn’t probably as satisfying as it should be,” he said in the statement. “It helps me avoid snacking too much at night.”