Co-creation refers to the collaborative approach of creative problem solving between diverse stakeholders at all stages of an initiative, from the problem identification and solution generation through to implementation and evaluation • Co-design describes active collaboration between stakeholders in the design of solutions to a pre-specified problem • Co-production refers to implementing previously determined solutions to a previously agreed problem with emphasis on the most efficient use of existing resources and assets

Background To make effective progress towards a global reduction in obesity prevalence, there needs to be a focus on broader structural factors, beyond individual-level drivers of diet and physical activity. This article describes the use of a systems framework to develop obesity prevention policies with adolescents. The aim of this research was to use the group model building (GMB) method to identify young people’s perceptions of the drivers of adolescent obesity in five European countries, as part of the EU-funded Co-Create project. Methods We used GMB with four groups of 16–18-year-old in schools in each of the five European countries (The Netherlands, Norway, Poland, Portugal and the UK) to create causal loop diagrams (CLDs) representing their perceptions of the drivers of adolescent obesity. The maps were then merged into one, using a new protocol. Results Two hundred and fifty-seven participants, aged 16–18 years, engaged in 20 separate system mapping groups, each of which generated 1 CLD. The findings were largely congruent between the countries. Three feedback loops in the merged diagram particularly stand out: commercial drivers of unhealthy diets; mental health and unhealthy diets; social media use, body image and motivation to exercise. Conclusions GMB provides a novel way of eliciting from young people the system-based drivers of obesity that are relevant to them. Mental health issues, social media use and commercial practices were considered by the young people to be key drivers of adolescent obesity, subjects that have thus far had little or no coverage in research and policy.

Introduction: Applying systems science in public health trials is a recent innovation in childhood obesity prevention. This paper aims to use systems science conventions to propose a theory of change for community-based interventions aiming to build capacity and use exemplars from systems science for obesity prevention to describe how this approach works.Methods: Participants were community-based researchers. A dynamic hypothesis was created in workshops conducted in 2020 and 2021 by identifying variables critical to building community capacity for systems thinking. These were used to develop stock and flow diagrams representing individual causal relationships, feedback loops, and the overall theory of change.Results: The resultant model identified 9 stocks and 4 pairs of central balancing and reinforcing feedback loops. These represented building commitment through relationships, mutual learning, strengthening collaboration, and embedding capacity. The model is described using examples from 3 trials involving 25 communities across Victoria, Australia. Conclusions:This nonlinear and practice-based model illustrates the process of community-based obesity prevention. The model integrates >20 years of community-based intervention implementation experience, providing an overarching theory of how such interventions work to create change and prevent obesity.

Systems thinking is increasingly applied to understand and address systemic drivers of complex health problems. In Australia, group model building, a participatory method from systems science, has been applied in various locations to engage communities in systems-based health promotion projects. To date there is limited evidence regarding GMB use with Australian Aboriginal communities. This study aimed to determine the value and acceptability of group model building (GMB) as a methodological approach in research with Aboriginal communities and identify any adaptations required to optimise its utility. Semi-structured interviews were undertaken with 18 Aboriginal health and university staff who had prior experience with a GMB research project. Interview transcripts were inductively analysed using thematic analysis and key themes were organised using an Indigenous research framework. Participants reported that GMB methods generally aligned well with Aboriginal ways of knowing, being, and doing. Participants valued the holistic, visual and collaborative nature of the method and its emphasis on sharing stories and collective decision-making. Group model building was viewed as a useful tool for identifying Aboriginal-led actions to address priority issues and advancing self-determination. Our findings suggest that by bringing together Aboriginal and non-Aboriginal knowledge, GMB is a promising tool, which Aboriginal communities could utilise to explore and address complex problems in a manner that is consistent with their worldviews. In adapting group model building methods, non-Aboriginal researchers should aspire to move beyond co-design processes and enable Aboriginal health research to be entirely led by Aboriginal people.

Background Community-based interventions have shown promise in reducing childhood overweight and obesity. However, they have been critiqued for using linear logic models. Participatory community-based systems approaches are posited as addressing the complexity of non-linear relationships in a local context. Community members are empowered to understand and describe obesity causation, identify and prioritise possible solutions. The application of such approaches to childhood obesity is in its infancy. Aim To describe the first 12 months of a participatory whole-of-community systems approach to creating collective action to tackle childhood obesity, called GenR8 Change, in a local government area of Victoria, Australia. Methods Three group model building (GMB) sessions focused on the development of a causal loop diagram (CLD), prioritised evidence-informed actions, and developed implementation strategies. The collective impact framework underpinned the approach, with a local backbone group supporting community members to implement prioritised actions. Results The first two GMB sessions included 20 key community leaders where a CLD examining the factors contributing to childhood obesity in the community was constructed and refined (22 variables GMB1, 53 variables GMB2). In the third session, 171 members of the wider community further refined the CLD, identified priorities for childhood obesity prevention (72 variables in final CLD). One-hundred and thirteen individuals signed up across 13 working groups to plan and implement 53 prioritised actions. Agreed community actions included creating sugar free zones; developing healthy policies; increasing breastfeeding rates; improving drinking water access; and increasing physical activity options. Twelve months post-GMB3, 115 actions had been implemented. Conclusion GenR8 Change is one of the first communities to apply systems thinking to childhood obesity prevention. Knowledge on how to collectively identify relevant leverage points to tackle childhood obesity can now be shared with other communities.