Generation Healthy Kids: Protocol for a cluster-randomized controlled trial of a multi-component and multi-setting intervention to promote healthy weight and wellbeing in 6–11-year-old children in Denmark

Abstract Background Childhood obesity can have significant negative consequences for children’s wellbeing and long-term physical health. In Denmark, the prevalence of overweight and obesity increases from 13% to 18% during elementary school and reaches 53% among adults, underscoring the importance of early prevention. Prior school-based interventions have shown limited effects on child weight development, which highlights the necessity for comprehensive approaches addressing the complex drivers of childhood obesity. “Generation Healthy Kids” (GHK) is a multi-setting, multi-component intervention aiming to promote healthy weight development, health and wellbeing in Danish children aged 6–11 years. This protocol describes the GHK main trial, which is a cluster-randomized trial evaluating the effectiveness and implementation of the GHK intervention. Methods During December 2022–May 2023, we recruited 24 schools (Capital, Zealand and Southern Denmark Regions) and randomly allocated them 1:1 to intervention or control. The intervention will run for two school years (October 2023–June 2025) and will include children in 1 st –2 nd grade at baseline (approx. n=1,600 children). The intervention will target multiple settings, including families, schools, after-school clubs, and local communities. Within four focus areas – diet, physical activity, screen media use, and sleep habits – the intervention incorporates several fixed elements, including a free school lunch program and three weekly sessions of physical activity at school. Furthermore, building on whole-systems thinking, the intervention will encompass co-created elements developed in collaboration with local stakeholders, including municipalities, sports- and leisure time organizations and supermarkets. This part of the intervention will emphasize building local capacity and engagement to promote child health and wellbeing. To evaluate intervention effectiveness, comprehensive data on child health and wellbeing will be collected from participating children and families at baseline and at the end of each school year. The primary outcome is fat mass measured by air-displacement plethysmography in the intervention- compared with control group at end-of-study. Furthermore, thorough process evaluation and tracking of community engagement will be performed. Discussion GHK combines evidence-based intervention elements targeting multiple settings with a whole-systems approach focusing on local capacity building and stakeholder involvement. This novel approach holds promise as an innovative way forward to promote child health and wellbeing and prevent childhood obesity. Trial registration ClinicalTrials.gov: NCT05940675