If you can’t stop eating cheese – who can? – there’s a scientific reason behind it. 

MIC – Each year, Americans consume over 35 pounds of cheese per person. In addition to those bricks of cheddar in our fridges, we’re eating cheese melted on pizza and quesadillas, folded into sandwiches and omelets, sprinkled on veggies and pasta… well, we don’t need to tell you.

While cheese is delicious, taste may not be the only reason we’re eating so much of the melty, fatty stuff. Cheese, as it turns out, may also be addictive.

The science: A recent University of Michigan study investigated which items serve as the drugs of the food world. Lo and behold, pizza topped the “addictive” list. So what makes it so hard to just have one slice?

The key quality of addictive foods, the study found, was processing: Unprocessed foods like salmon or brown rice were not associated with addictive eating behaviors, while highly processed foods like French fries and potato chips were. And many processed foods have one thing in common: fat. “Fat seemed to be equally predictive of problematic eating for everyone, regardless of whether they experience symptoms of ‘food addiction,'” Erica Schulte, one of the study’s authors, told Mic.

At the top of the list of fatty, processed foods are items with cheese, including pizza. And as it turns out, in addition to sugar of the tomato sauce and the carbs in the crust lighting up our brain’s dopamine receptors (the chemicals often linked to addiction), there’s a specific ingredient in cheese that gets us hooked — a chemical called casein.

Read more: MIC