Arm-chair psychiatrist-ing here, but it seems to me like people who are willing and capable of thinking about their diet at this level of complexity would be mo

Arm-chair psychiatrist-ing here, but it seems to me like people who are willing and capable of thinking about their diet at this level of complexity would be more likely to do well on tests. I wonder what the results of the study would be if they had these same people eat whatever they wanted, but do the meal planning for a third person?