What did you have for breakfast this morning? Are you a grab-a-muffin-and-go kind of person? Or maybe you prefer a heartier, protein heavy breakfast? You know … eggs and bacon with a slice of whole-grain toast?

Well, it turns out, that decision could matter for more than your waistline. According to the senior author of a new study, Dr. So Young Park from the University of Lü​beck says what you eat could influence decisions you make.

She and her colleagues found that when people ate carbohydrate-heavy breakfast, they were much more likely to punish a person for making an unfair offer in a pscyhological game known as the Ultimatum Game. The reason for this? If you eat a breakfast that's higher in protein, you make more tyrosine, which is a precurser to dopamine — a neurotransmitter in the brain that affects decisions we make.