"Hyperactive..." Is this a clinical term, or just some clinical sounding excuse that lousy parents use to justify punishing / drugging their kids?
I believe there are some studies that look specifically at ADHD and similar diagnoses, so that would be one part of "hyperactive". But even apart from controversy regarding over-diagnosis of ADHD in children, Id say that a long term medical diagnosis of ADHD isnt necessarily what most people are talking about when they say "sugar makes their child hyperactive". Theyre talking about a specific short term causative effect.
Plus, which "sugar" are we talking about? Glucose, sucrose, fructose? What about lactose in milk?
My understanding is that there are studies of varying quality that come down on both sides of the issue, but that there are a number that investigate and demonstrate a significant amount of placebo effect / observer bias is involved - eg, a study where both groups of supposedly sugar-sensitive children were given a placebo had the parents of one group told they had been given sugar and those parents reported their children as significantly more "hyperactive".
Theres also some studies and reviews that question, if there is a correlation with long term diagnoses like ADHD, whether the cause and effect might be reversed - that some ADHD sufferers are known to self-medicate in observable ways such as drugs and that behavioural over-eating could be another coping mechanism in the same sort of manner, with high-sugar foods being one of those foods. Higher incidence of sugar-rich foods in their diets would then be a result of
the hyperactivity, not a cause