A recent study published in PLoS one found that trans-fat consumption was associated with increased levels of aggression. In fact, the researchers found that trans-fat consumption was a better predictor of aggressive behaviour than commonly used predictors of aggression. Of course, this was an observational study as it would be unethical to assign people to diets high in trans-fat so we can’t say for certain that it was the consumption of trans-fat that was the cause of the aggressive behaviours. However, there was a strong link between these two factors so it is quite plausible that diets high in trans-fat may increase aggressive
I recall reading a study a number of years ago (which I can’t seem to find a link to) that showed a relationship between diet and risk of re-offending for juvenile offenders. The researcher for this study suspected that a nutritionally deficient diet might be contributing to the criminal activities of juvenile offenders. The offenders were then provided with a nutritious diet whilst in detention and it was found that the behaviours of those fed the healthy diet were significantly improved and following release they were less likely to re-offend.
I find links between behaviour and diet fascinating (my first degree was in psychology and I still love learning about the field). I think it shows that diet affects us in many ways that we are not consciously aware of. It’s commonly accepted that a healthy diet can help to keep our bodies healthy. Beyond that, what we eat may have important implications for our mental health as well.