Using Social Simulation to Understand the Obesity Epidemic in the United States

Despite a growing concern for the obesity epidemic in the United States, data constraints have limited social science analyses to correlative studies. This limits our capacity to make causal statements about which factors contribute to weight gain. This is further compounded by the fact that the nature of the obesity problem is plagued with several endogeneity problems. Currently, no national database within the United States concurrently collects longitudinal data on individuals’ weight outcomes, dietary intake and economic and geographic indicators. However, this form of data is necessitated by traditional econometric approaches in order to treat endogeneity and thus has thwarted the advancement of the study of obesity as a social problem. For this reason, I approach the obesity epidemic as a complex system. Wherein by, endogeneity is not only integrated into the model, but is regarded as an autonomous factor contributing to micro and macroscopic outcomes of the system. In this sense I have characterized the obesity problem as an adaptive system where people’s actions and preferences are governed by their local environments, history of food choices and consequently, their changed weight status as a result of those choices over time. I am particularly interested in the consumptive behavior of individuals by income class. I theorize that the lowest income individuals will tend to be the most obese because they are relegated to food choices that are calorically dense, but nutrionally lax and thus will tend to over-consume. Results show that in fact the lowest income individuals do not tend to be the most overweight. Rather, it is the middle class that exhibits the highest preponderance of obesity. This suggests that poor individuals are still dominated by a large negative income effect and simply do not possess enough purchasing power to consume a sufficient number of calories. While, middle class individuals—despite the ability to purchase an abundance of calories— may still be out priced by health and may over consume to compensate for nutritional deficiencies. When a tax is applied there is a shift of burden of obesity to the upper middle class since real income is deflated and as such middle class individuals lose some purchasing power which would otherwise enable them to increase their obesity status.