Keywords: Childhood obesity-related behaviours; Causal loop diagrams; Complex interventions.

Author Karien Stronks on the article: 

Despite continuous efforts to reduce the burden of childhood overweight/obesity, we see disappointing results, where not a single country has successfully halted the obesity epidemic to date. One explanation for this lack of progress is that most existing approaches, although multicomponent, focus on causes of obesity directly related to unhealthy behaviours, such as (lack of) health knowledge, or unhealthy school environments. Most programs do not take into account the complexity of the problem, including underlying mechanisms that drive these unhealthy behaviours such as stress, peer pressure, or the political environment nor do they take into account dynamic properties, including feedback and adaptation in response to changes (i.e., interventions) in the system. A recent review of 13 systematic reviews of interventions aimed at preventing overweight/obesity in adolescents concludes that the evidence base for the effectiveness of current interventions is weak, in particular because the vast majority of included interventions target the individual and are set in schools with a lack of structural and environmental interventions applied in the wider society.

This lack of a sustainable impact aligns with the conceptualization of overweight and obesity as a complex problem: the drivers are multiple, diverse, and dynamic, ranging from biological factors and personal behaviours to aspects of the physical, economic, sociocultural, and political environments that shape those drivers. Systems thinking is acknowledged as a promising approach to understanding and responding to the complexity of the obesity epidemic. Although there is a growing body of literature on applying systems thinking in public health research, there is still relatively little guidance on how to create an understanding of systems dynamics and design and evaluate public health interventions in complex systems.

This paper reports how we applied systems dynamics methods to gain insight into the complexity of obesity-related behaviours in youth, including diet, physical activity, sedentary behaviour, and sleep, by integrating a literature review into causal loop diagrams (CLDs). The results presented in this paper are part of a larger program entitled Lifestyle Innovations Based on Youth Knowledge and Experience (LIKE) (www.like-onderzoek.nl). 

Results showed that the CLDs consisted of multiple subsystems and three types of dynamics appeared, including (1) feedback loops, (2) connections between feedback loops and subsystems, and (3) mechanisms. We observed clear similarities in the dynamics for the four behaviours in that they relate to “traditional” subsystems, such as home and school environments, as well as to newly added subsystems, including macroeconomics, social welfare, and urban systems. The CLDs provided insights that can support the development of intervention strategies, including (1) the confirmation that a range of mechanisms cover and connect multiple levels and settings, meaning that there is no silver bullet to address obesity; (2) understanding of how interventions in one particular setting, such as school, might be influenced by the interactions with other settings, such as urban systems; and (3) a comprehensive view of (un)intended consequences.

This way of framing the problem will assist moving towards public health interventions that respond to and operate in the complexity of the real world.

Waterlander, W. E., Singh, A., Altenburg, T., Dijkstra, C., Luna Pinzon, A., Anselma, M., Busch, V., Houtum, L. van, Emke, H., Overman, M. L., Chinapaw, M. J. M., Stronks, K. (2021) Understanding obesity-related behaviors in youth from a systems dynamics perspective: The use of causal loop diagrams. Obesity Reviews; 22:e13185. https://doi.org/10.1111/obr.13185