It is widely believed that sugar triggers hyperactivity in susceptible children. Careful research studies have failed to confirm this notion but have suggested that an apparent relationship between sugar and hyperactivity in children arises from what parents and carers choose to believe.
Sugar and hyperactivity
Children, especially young children, tend to become lively and energetic when playing with their friends, especially on special occasions, such as a birthday party. It is also common experience that they become more active after a meal. Sometimes, their behaviour is too energetic and almost disruptive for adults to accept.
It has been suggested that these every day experiences may be attributed to something the children have eaten that triggers unacceptable behaviour. Among a number of suggested candidates is sugar.
Studies attempting to test this hypothesis need to be conducted with care, since children’s behaviour is strongly modified by circumstance and by the presence of some adults. These complications can be addressed by appropriate study design, and a number of investigators have observed the behaviour of children, under suitably controlled conditions, following consumption of sugar-containing foods and drinks. These studies have included some of children whose parents believe they react adversely to sugar.
The results of this research are illuminating. The studies have consistently shown that, when assessed by impartial observers, unaware of which children had consumed sugar and which had not, there was no deterioration in the behaviour of the children that can be ascribed to the consumption of sugar.
More interestingly, when the parents assessments were examined, these showed that the children’s behaviour was perceived to deteriorate only when the parents believed the children had consumed sugar, irrespective of whether they had or not. This is a clear case of observer bias. The belief of the parents determined their perception of what they were observing in their children. It bore no relation to what was really happening.
The evidence is therefore unusually clear. Sugar does not cause hyperactivity in children. It is noteworthy that this conclusion is not based on the mere absence of evidence of any adverse effect of sugar on children’s behaviour but on concrete, controlled experiments showing no effect.