Half of parents underestimate the weight of their overweight or obese children.

Implications for practice and research: Parental underestimation of child weight is widespread and is a barrier to engagement with obesity interventions. Correcting parental perceptions may be of limited benefit if perceptions are not accompanied by changes in perceived health risk and lifestyle. Research is needed to identify effective interventions for encouraging healthy lifestyle behaviours among families, regardless of their child's weight status.