A study in 2017 finds that the composition of food in one meal can significantly affect behavior in the following hours, higher carbohydrate meals increase punishment behavior. How does this work and what does it mean in terms of understanding how diet affects mood?

In the study, a high carbohydrate breakfast boosted tryptophan and lowered tyrosine. Tryptophan is the key building block for brain serotonin and tyrosine is the key building block for dopamine.

Those with the high carbohydrate breakfast were twice as likely (50% vs 25%) to punish an unfair offer in the “Ultimatum Game” that morning – perhaps reflecting a greater tendency to punish behavior outside the norms for social conduct.

Tyrosine levels appeared to be the key to predicting behavior.

This picture summarizes the findings.

Higher Carbohydrate Meals Increase Punishment


Strang S et al. Impact of nutrition on social decision making. Proc Natl Acad Sci U S A 2017 Jun 20; 114:6510