FactSentinel

Verdict: False.

Controlled studies have not found that sugar directly causes hyperactivity in children. A well-known meta-analysis in JAMA reviewed controlled trials and concluded that sugar did not affect children's behavior or cognitive performance in the way the popular claim suggests.

The belief is understandable because sugary foods often appear at birthday parties, holidays, school events, and other exciting settings. Children may be more energetic in those settings because of the event, sleep disruption, group play, or adult expectations. Some studies have also shown that when parents believe a child has consumed sugar, they may rate the child's behavior as more hyperactive even when the child did not receive sugar.

This fact-check does not say high sugar intake is healthy. Excess added sugar can contribute to dental problems, excess calories, and other health risks. The narrower claim that sugar itself causes hyperactivity is not supported by controlled evidence.

Sources reviewed:
JAMA meta-analysis: https://jamanetwork.com/journals/jama/article-abstract/391812
CDC added sugar guidance: https://www.cdc.gov/healthy-weight-growth/be-sugar-smart/index.html
American Academy of Pediatrics nutrition guidance: https://www.healthychildren.org/