Supporting a systems approach to healthy weight interventions in British Columbia by modeling weight and well-being

The use of simulation models for policy development within the obesity field has grown very quickly over the last years. Nonetheless, the develop of comprehensive models is still in its infancy in part due to the difficult of integrating knowledge about the physiology, physical activity, diet, and well-being of an individual. In this paper, we designed and implemented a deterministic System Dynamics model that includes over 30 factors from these domains. The model's primary purpose is to identify combinations of factors within an individual that would be candidates for obesity policies in British Columbia (BC). Thus, it captures a single individual representing the average adult BC resident. The model was designed through a collaborative approach involving one-on-one expert interviews (for soft variables and overall model structure) and recent epidemiological evidence. The model was validated through sensitivity analysis to extreme conditions, dimensional consistency of equations, and most importantly whether the model satisfactorily reproduced real-world observations about obesity and well-being. While this model can serve to find leverage points for the average BC individual, additional studies are needed to determine what the policies would be at the population level and how to coordinate them across organizations.