Relationships between aggression, activity, sugar, and aspartame were investigated in 30 preschool boys: 18 had histories of behavioral reactions to sugar and 12 were familiar peers whose parents reported their children were not sugar reactive. Analysis of week long diet diaries found no significant differences in sugar or carbohydrate consumption between the two groups nor were correlations reported previously by another group between weekly sugar consumption and observed activity and aggression replicated. Furthermore, aggression did not increase in response in blinded sugar challenge. A significant statistical but negligible decrease in actometer activity was observed following aspartame. The likelihood of behavioral reactions to aspartame seem questionable.