A dynamic model for evaluating the effects of changes in eating and physical activity on childhood obesity

Obesity is a term used to describe the condition of excess fat. It has many dangerous sideeffects for health and well-being. Knowing the negative impacts of obesity, this researchattempts to demonstrate the contribution offered by system dynamics modelling with the modelbeing used as an experimentation tool to investigate the combined impact of eating andphysical activity behaviour on average weight, body mass index and the prevalence of obesitytrends of the English child population aged 2 to 15 years. In an effort to uncover the mosteffective interventions to achieve desirable weight targets by 2020, this study considers howmodifications in the forces which influence behaviour might be modelled at the populationlevel; this is an emerging interest in the system dynamics community. This research combinesdifferent strands of knowledge from nutrition, physical activity, body metabolism and sociopsychologicaltheory, synthesising this knowledge in a system dynamics model by highlightingthe interrelations between these various strands in one complex human weight regulationsystem. The model offers unique insights into the dynamics by capturing the complexinterdependencies from the stock and flow feedback structure, non-linear relationships anddelays, all of which exist in the public health system surrounding obesity. The results from thisresearch support previous studies in this area. However, this study also highlights causalexplanations for the variability of the findings which had not been surfaced before. In respectof the baseline model it is assumed that the weight profile of the English child population wasnot particularly abnormal around forty years ago. However, with increases in energy-densefood consumption, especially from fat and outside meals, combined with reductions in physicalactivity and an increase in sedentary behaviour at the same time, the average weight, body massindex and obesity trends have increased dramatically, especially so since the 1990s. Findingsfrom this research also provide insights that a combination of modifying food intake, reducingsedentary behaviour and increasing physical activity form the basis of the most effectiveinterventions for obesity control in the English child population. This research also suggests adefinite failure to achieve a reversion of 2020 obesity data to that observed in 2000. The modelindicates that a much longer intervention period will be needed to significantly reduceoverweight and obesity in this population. Governments and other public agencies need to carryout modelling studies before setting public health targets. Finally, this research also highlightsparents' contribution to ameliorating childhood obesity