What Causes Obesity? And Why Has It Grown So Much?

In recent years, economists have attempted to explain the rising levels of obesity not only in the United States during the last three decades, but also in many developed countries. For the most part, these economists’ models have utilized neoclassical economic tools and relied on the conventional wisdom of health science practitioners. The results of this theorizing have been disappointing at best. The main purpose of this chapter is to develop an alternative socioeconomic model of obesity based more on behavioral economics concepts and on an alternative to the conventional health science wisdom. The development of this model is important because it involves an attempt at a novel synthesis of all the key factors contributing to the obesity problem. Instead of fully rational economic decision makers, this chapter assumes decision makers are partly or limitedly rational. Instead of weight gain and obesity being strictly determined by the amount of calories consumed minus the calories expended, weight gain is determined much more by what people eat. Also, the weight-obesity outcome is determined by how different people respond to the growing infrastructure of obesity (notably the suppliers of fast food and processed foods). In general, obesity in the present model is the result of individual decisions to choose poor diets and poor life behavior patterns (including exercise). Unlike in the rational obesity model, these are not decisions of rational economic men or women.