There's no better way to kick off the day than with a healthy breakfast. But we never realised before now that this age-old adage has behavioural advantages too.
People are more forgiving and tolerant when they've eaten a low-carb breakfast, according to a new study.
Researchers from the University of Lübeck in Germany found that those who replaced carb-based food with proteins in the first meal of the day made more magnanimous decisions in a card game a few hours later.
This is possibly because protein boosts levels of dopamine in the brain, which in turn makes us less aggressive and more open to being satisfied, the New Scientist reports.
Can eating a carb-heavy breakfast really make you meaner?
Soyoung Park and her team asked 87 people what they had eaten for breakfast that morning, before asking them to play an "ultimatum game" that involved splitting money with their allocated partner.
Those who had eaten a low-carb meal were 28% more likely to accept an unfair offer, compared to those who'd enjoyed a breakfast that was high in carbs.
The researchers then repeated the experiment with a new set of people, whom they actively fed a low or high-carb breakfast to. The results were very similar; those who'd had the low-carb option were more forgiving in their decisions.
Park speculated that a low-carb, high-protein breakfast triggered a higher baseline dopamine level amid those who'd eaten it. And because dopamine signals rewards, they were more likely to find a lower offer from their partner acceptable in the card game.
Higher dopamine levels could also have resulted in participants being less aggressive and more rational.
While more research is needed, the study suggests diet can indeed influence people's behaviour.
The survey was published in the journal Proceedings of the National Academy of Sciences.
Read More: Why You Should Never Skip Breakfast