OBESITY | VOLUME 18 SUPPLEMENT 1 | FEBRUARY 2010 S13 nature publishing group COMMENTARIES CHILDHOOD OBESITY 1 Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada; 2 National Obesity Observatory, Oxford, England. Correspondence: Diane T. Finegood (Finegood@sfu.ca) Shifting the paradigm Our understanding of the causal factors that contribute to the obesity epidemic has evolved over time. Although some still describe the problem as “people eat too much and move too lit- tle,” this articulation has not brought us closer to understanding what to do to reverse current trends. Various conceptual mod- els have framed the problem of obesity in diferent ways. Bray suggested an epidemiological model which illustrates agents such as food, viruses, and toxins acting on a host to produce disease, and a homeostatic model where fat acts on the brain (controller) which in turn feeds back to act on the fat (con- trolled system) (1). He described the interpretation of these models as “genetic background loads the gun, but the environ- ment pulls the trigger” and suggested they imply the need for a simple FLOURIDE (For Lowering Universal Obesity Rates Implement ideas that Don’t demand Efort) solution. he International Obesity Task Force expanded on the con- cept of environmental agents by introducing its “causal web” (2). In the causal web, environmental factors are illustrated as “black boxes” such as school food and activity, public trans- port and urbanization. hese factors are organized in columns according to their proximity to the individual, i.e., factors asso- ciated with work/school/home, community/locality, national/ regional, and international levels. Distal contextual factors such as globalization of markets, and media and culture are shown to act on more proximal factors which in turn act on energy expenditure and food intake. he connections are sim- ple one way arrows and biological factors are not included. he causal web helps to illustrate the diversity of factors afecting individuals and suggests that we will need to implement many ideas that “don’t demand efort” on the part of the individual. Although the causal web suggests the challenge of addressing obesity is complicated, it does not explicitly illustrate the prob- lem as “complex”. Absent from the causal web is consideration of the feedback loops which are a hallmark of complex adap- tive systems. More recently the Foresight Programme of the UK Government Oice for Science published an obesity sys- tem map, developed through a multistakeholder process (3). his qualitative, conceptual model has 108 variables, some of which are measureable (e.g., the ambient temperature of the indoor environment), and other variables that are more dii- cult to quantify (e.g., desire to diferentiate food oferings). he relationships between the variables are illustrated with >300 solid or dashed lines to indicate positive and negative inlu- ences. All the variables are interconnected, some with large numbers of inputs and others with large numbers of outputs. he connections give rise to feedback loops with as few as two variables (e.g., a afects b which in turn afects a) or involving as many as 16 variables. At the core of the map is “energy bal- ance” (energy intake vs. energy expenditure). he core (also referred to as the engine) is surrounded by variables that dir- ectly or indirectly inluence energy balance. hese variables are clustered in seven themes ranging from Food Production to Physiology. Apart from the physiological cluster, most of the variables can be considered on an individual, family, group, or societal scale. For example, the “level of physical activity” can be considered for a particular individual or as an average for the whole population. he Foresight obesity project articulated the ambitious goal of deining the obesity system as “the sum of all the relevant factors and their interdependencies that determine the con- dition of obesity for an individual or a group of people” (3). Although the notion that the process could give rise to a map of “all” relevant factors was perhaps over ambitious, the map efectively illustrates the complexity of obesity by highlight- ing the interdependencies among variables as diverse as the pressure on the food industry to cater for acquired tastes and conscious control of an individual’s accumulation of energy. he map is dominated by its illustration of the connections and feedback loops between variables. Although the map cannot be considered comprehensive, its construction engaged a broad range of stakeholders, including scientists, the private sector and government departments in a dialogue about how to tackle this wicked problem (4). he dia- logue helped to forge multisector, multidisciplinary relation- ships that support future government decision making based on evidence (4). An enduring value of the map is its use as a heuristic. It illustrates the complex multifactoral nature of the systems that give rise to obesity and it can be used to stimulate an even broader discussion among relevant actors ranging from multiple government departments to school age children (5,6). In this way the map helps the development of a more sophisti- cated and integrated policy approach. he Foresight program on obesity gave rise to the work of organizations such as the English National Obesity Observatory (NOO) (http://www. Implications of the Foresight Obesity System Map for Solutions to Childhood Obesity Diane T. Finegood 1 , Thomas D.N. Merth 1 and Harry Rutter 2