Like a moth to a flame, you’re drawn to the florescent glow of the refrigerator light, what with the leftover spaghetti and meatballs, cold pepperoni pizza, and scrumptious week-old birthday cake that’s lurking in there. As you probably know, giving into these late-night cravings is not a good move for your waistline. Still, how many times have you found yourself spooning ice cream into your mouth after dinner without being able to stop?

Finally, a new study may explain exactly why those midnight munchies are so hard to control: Researchers from Brigham Young University put 15 women on the same eating plan and had them hop into an fMRI machine for a brain scan while they were shown a series of 360 pictures featuring both healthy, low-calorie foods and crave-worthy, high-calorie foods. They did the experiment twice—once in the morning and again at night, a week later. In the end, they found lower reward-related activity in the brain at night in response to high-calorie foods than they did in the morning.

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This could mean that at night, you don’t get the same rush of satisfaction that you might get during the day, leading you to crave snacks even more.

“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 news release. “It may not be as satisfying to eat at night, so you eat more to try to get satisfied.”

“We thought the responses would be greater at night because we tend to over-consume later in the day,” study co-author Lance Davidson added in the release. The lackluster neural response in the evening likely means that your brain doesn’t register the food you’re eating as well, so your impulse is to keep on eating in search of the pleasure you’re used to getting out of it.

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Masterson and Davidson also found that the participants were more distracted by food when they tested them in the evening, and thought they could eat more, even though their reported hunger and “fullness” levels were the same as during the day.
On top of that, the study participants were told to avoid eating for certain periods before each test. “They should have been less hungry at night because the fasting period was shorter,” Masterson told to CBS News. “We know that there is something going on here.”
Eating a well-rounded dinner with protein, healthy fats, whole grains, and fiber can help ward off the trip to the fridge in the first place. But if you know you’ll snack regardless, prep some low-cal options like carrots and hummus ahead of time and stick them front and center in your fridge, and keep the indulgent goodies out of sight.

Masterson’s own research is already working for him. When he feels a siren call to the fridge after-hours, “I tell myself, this isn’t probably as satisfying as it should be,” he said. “It helps me avoid snacking too much at night.”

This article originally appeared on Health.com. http://news.health.com/2015/05/07/the-real-reason-why-you-cant-stop-snacking-at-night/