Gooey pizza, butter-rich chocolate chip cookies, scrumptious cheese fries — the right combo of fats and carbs can be oh-so-delicious!

And, oh-so difficult to resist. A study published in the journal Cell Metabolism reveals that delectable fat and carbohydrate combinations can have a strong influence on the striatum, [stry-AH-tum] one of the brain’s reward centers.

An international group of scientists reached this conclusion by playing a game of sorts with about 200 study participants. They showed the subjects images on a computer screen of various snacks, all containing the same numbers of calories. Snacks included carb-rich foods, fat-heavy foods and combo foods. Then, participants had to select how much money they would pay for their favorites.

The snacks comprising both fat and carbs garnered the most “money” from game participants. They also elicited a bigger response from the reward centers of their brains, as shown by brain scans conducted during the game.

The researchers found that people had a tough time accurately assessing the calorie content of the combination foods, and tended to overestimate it. In the hunter-gatherer world in which our ancestors lived, where getting enough to eat was a daily challenge, such overestimations would have heightened a food’s appeal.

These two phenomena — valuing combo foods more than fat- or carb-only items, and overestimating calories in a combo food — help explain modern man’s love of processed junk food, which tends to combine both. But many experts say the body is not well-equipped to burn fat and carb calories simultaneously, and will store one or the other. That, unfortunately, is a recipe for weight gain.