Combating childhood obesity: Discovery and translation of evidence for new strategies to enhance behaviour change

Childhood obesity is a significant public health concern in Australia and across the world, with implications for current and future health services. Parent-involved treatment interventions incorporating multiple behavioural components to address the complex variables of obesity are essential in school-age children to prevent physical and psychological comorbidities tracking into adulthood. However, there is a need for greater understanding of the relationships between behaviour change techniques, mechanisms of behaviour change and behavioural outcomes. Behavioural and psychological literature also suggests that the use of incentives to support behaviour change through goal achievement may improve health outcomes related to healthy eating and physical activity. However, there is a lack of robust research on the potential of such schemes and their optimal implementation into future programs in school-age children in the context of family-based behavioural treatment programs (FBTs). Overall, this thesis aimed to contribute to a reduction in childhood obesity through discovery and translation of evidence for a novel strategy to enhance behaviour change. Specifically, the research addressed a gap in the literature on the use of theory to explain mechanisms of change and the motivational impact of incentives on health behaviours in children. In this thesis, the potential role of incentives in health-related behaviour change and implications for future research and translation was investigated through a narrative literature review. Subsequently, the role of parental involvement in FBTs, key characteristics of programs that contribute to positive dietary and physical activity behavioural outcomes, and the key behaviour change techniques and psychosocial variables facilitating behaviour change were investigated through a systematic literature review with realist analysis. This was to build greater contextual understanding on what works and how specifically in FBTs focusing on school-age children incorporating a range of behavioural techniques and including behavioural outcomes. Using the evidence-based concepts identified in the literature reviews as a foundation for analysis, the impact of a multicomponent incentive strategy on dietary and physical exercise behaviour change in school-age children was investigated through two qualitative evaluations. A process evaluation determined motivators to engagement within the strategy to improve attendance and health-related behaviour change in an existing theory-based FBT for overweight and obese children. An impact evaluation determined the contextual factors, including family attitudes towards incentivising children, and active behaviour change components influencing the behavioural outcomes of the strategy. Collectively, the research presented in this thesis highlight three key areas of importance for future treatment interventions to consider; promoting intrinsic motivation, involving the parents, and using incentives for enhancing engagement and retention. Specifically, this research identified that promoting intrinsic motivation and self-efficacy within parents involved in behavioural interventions can support dietary and physical activity behaviour change in school-age children. The involvement of parents in behaviour change strategies was key for supporting behaviour change in participating children, and a short-term role for incentives was identified in enhancing longer-term habit formation via motivating families to continue attending a weight management program. Additional research is required to further understand how best to foster continued intrinsic motivation for sustained behaviour change. The results are important for assisting researchers, community health practitioners and policy makers in the development, implementation and translation of novel behaviour change strategies in FBTs for obese children using a range of behavioural techniques. Findings may also apply to a range of chronic conditions with similar treatment intervention approaches indicated. Ethical approval for this research was given by the South West Sydney Human Ethics Committee review body (HREC/14/LPOOL/480)