I expect this has been done before, but I still hear people talking about sugar as though it has some connection to hyperactivity so I thought I'd post it.
Sugar and hyperactivity - scroll down a bit
Many parents believe that sugar makes their children more restless and hyperactive, and deliberately limit their intake of sweets and fizzy drinks accordingly. Yet this supposed link has been extensively researched and does not hold up well. Dr Vreeman and Dr Carroll found 12 double-blind, randomised controlled trials investigating the issue, and not one found differences in hyperactivity between those who consumed large amounts of sugar and those who did not.
Studies have found that when parents think that their children have been given a sugary drink, even when it is sugar-free, they rate their children's behaviour as more hyperactive. ?The differences were in the parents' minds?, the researchers said.>>