Unless you’re one of those rare people who doesn’t like sweets, the lure of a glazed or powdered doughnut is often too powerful to resist. The next time you succumb to that second or third Boston cream, don’t blame it on weak willpower—blame it on your brain.

As the New Scientist reports, a Yale University study published in the journal Cell Metabolism provides new evidence that foods rich in both carbohydrates and fats fire up the brain’s reward center more than most foods. For the study, volunteers were shown pictures of carb-heavy foods (like candy), fatty foods (like cheese), and foods high in both (like doughnuts). They were then asked to bid money on the food they wanted to eat most, all while researchers measured their brain activity.

Not only were volunteers willing to pay more for doughnuts and similar foods, but foods high in carbs and fat also sparked far more activity in the striatum, the area of the brain where dopamine is released. (Chocolate is one of the foods most commonly associated with increases in dopamine, working in the same way as drugs like cocaine and amphetamines.)

Presented with these findings, researcher Dana Small theorized that the brain may have separate systems to assess fats and carbs. Modern junk foods that activate both systems at once may trigger a larger release of dopamine as a result.

This study doesn’t entirely explain why different people crave different foods, though. Much of it has to do with our habits and the foods we repeatedly gravitate towards when we want to feel happy or alleviate stress. Another study from 2015 found that certain treats associated with high levels of reward in the brain—like pizza, chocolate, chips, and cookies—were considered to be the most addictive foods (doughnuts didn’t make the top 20, though).

It's still possible to turn down foods that are bad for you, though. While many people try to improve their self-control, one of the most effective ways to avoid an undesired outcome is to remove the temptation completely. Free doughnuts in the break room? Stay far away.

[h/t New Scientist]