Parents often blame candies and other high-sugar foods when children get unruly. Some insist that sugar triggers hyperactivity. However, when put to the test, the sugar-behavior link does not hold up.
In a carefully controlled study of preschool and school-aged children, researchers found no effect on behavior or ability to concentrate when sugar intake was far above normal, even among those whom parents identified as “sugar sensitive.” Another study found that sugar had the opposite effect to what was expected—when boys whose parents believed them to be sugar reactive were each given a large dose of sugar, they were actually less active than before. Finally, several studies comparing blood glucose levels have found that children with attention-deficit/hyperactivity disorder (ADHD) have exactly the same response to sugar consumption as do children without ADHD. There is no scientific basis for claims that sugar and other sweeteners influence behavior or cause ADHD, even at levels many times higher than in a normal diet. The overactivity children show after a birthday party or Halloween may be due more to the stimulation of the event than the sugar.
Special diets for hyperactivity are based on the belief that allergies or reactions to foods cause undesirable behavior. The diets typically target artificial additives, sugar, or the commonly allergenic foods (ie, corn, nuts, chocolate, shellfish, and wheat). However, there is no evidence that links foods and behavior.
Some studies show that chemical preservatives or dyes, presumably through a drug rather than allergic mechanism, might contribute to these problems, but the evidence is weak and not widely accepted by experts. Therefore, the American Academy of Pediatrics does not recommend special diets for treating hyperactivity. If your child behaves oddly or has unusual symptoms after eating a particular food, it will do no harm to avoid it, provided his diet includes other choices from the same food group.