Blindspot in the evidence base: A systematic review of psychological interventions for children and adolescents with intellectual disabilities and co-occurring obesity

•Review finds paucity of evidence on weight management for children with intellectual disabilities and obesity.•Behavioural research and interventions typically exclude children and adolescents with severe-profound intellectual disabilities.•Interventions benefit from parental engagement, collaborative and individualised goal setting, and multidisciplinary teams.•Intervention framework proposed for children with Down, Bardet-Biedl and Prader-Willi Syndromes.