If you go through meetings with a scowl on your face, your breakfast could be the problem. A recent study has come to the conclusion that breakfast can affect human social behavior. The small-scale study, published in the Proceedings of the National Academy of Sciences, noted that out of 111 participants, those who ate high-protein foods for breakfast were more easy-going while making business decisions than those who ate carbohydrate-rich foods. Study participants who started the morning with a breakfast high in carbs were quicker to become annoyed by unfair financial offers. The study claims that “in a limited sense, ‘we are what we eat’.”

By having participants eat breakfasts with different macronutrient compositions and then participate in a simulated financial deal, the administers of the study came to the conclusion that the meal had a controlling influence on the subjects’ social behavior. After digesting breakfast, participants played an economic and psychological game known as the Ultimatum Game, which results in an unequal division of money among players, with some people getting no money at all. The scientists discovered that participants who’d filled up on carbs were more likely to choose the lose-lose outcome, characterized as social punishment behavior. Those who were running on protein were more likely to accept a deal that was unfair to themselves, but left both parties with money.

One of the researchers on the study, Soyoung Park of Germany’s University of Lübeck, explained to HealthDay the science behind the breakfasts. Park’s team found the high-carb breakfast eaters displayed lower levels of an amino acid known as tyrosine. Said Park: “Tyrosine is important in producing brain chemicals like dopamine—which is part of the brain's ‘reward system’.” Park also noted that changes in tyrosine paralleled changes in people's decisions.

When speaking to IBTimes UK, Park explained that the carb-eaters’ behavior was shrewd, but indicates a spiteful edge. "When they reject the [deal], no one gets any money,” Park said. “So they're punishing the other person, and rejecting their own money.” 

While the study was too small to make any grand conclusions, the researchers’ findings were still clear. And ultimately, whether it’s good for business that people who eat protein in the morning are more likely to be easy-going than those who eat carbs probably depends on the individual’s job. While you may want to hand your boss a stick of jerky before the morning staff meeting, those who work in politics should probably consider grabbing a bagel.