FAST FOOD DEBATE

Fast food debate

Fast food debate

Introduction

The prevalence of obesity and obesity related diseases has increased rapidly in the U.S. since the mid 1970s. At the same time, the number of fast food restaurants more than doubled over the same time period, while the number of other restaurants grew at a much slower pace according to the Census of Retail Trade (Chou, Grossman, and Saffer, 2004). In the public debate over obesity it is often assumed that the widespread availability of fast food restaurants is an important determinant of the dramatic increases in obesity rates. Policy makers in several cities have responded by restricting the availability or content of fast food, or by requiring posting of the caloric content of the meals (Mcbride, 2008; Mair et al. 2005).

But the evidence linking fast food and obesity is not strong. Much of it is based on correlational studies in small data sets. In this paper we seek to identify the causal effect of increases in the supply of fast food restaurants on obesity rates. Specifically, using a detailed dataset on the exact geographical location restaurant establishments, we ask how proximity to fast food affects the obesity rates of 3 million school children and the weight gain of over 1 million pregnant women. For school children, we observe obesity rates for 9th graders in California over several years, and we are therefore able to estimate cross-sectional as well fixed effects models that control for characteristics of schools and neighborhoods. For mothers, we employ the information on weight gain during pregnancy reported in the Vital Statistics data for Michigan, New Jersey, and Texas covering fifteen years.1 We focus on women who have at least two children so that we can follow a given woman across two pregnancies and estimate models that include mother fixed effects.

Discussion While it is clear that fast food is generally unhealthy, it is not obvious a priori that change in the availability of fast food should be expected to have an impact on health. On the one hand, it is possible that proximity to a fast food restaurant simply leads local consumers to substitute away from unhealthy food prepared at home or consumed in existing restaurants, without significant changes in the overall amount of unhealthy food consumed. On the other hand, proximity to a fast food restaurant could lower the monetary and non-monetary costs of accessing unhealthy food. In addition, proximity to fast food may increase consumption of unhealthy food even in the absence of any decrease in cost if individuals have self-control problems. Ultimately, the effect of changes in the supply of fast food on obesity is an empirical question. We find that among 9th grade children, the presence of a fast-food restaurant within a tenth of a mile of a school is associated with an increase of about 1.7 percentage points in the fraction of students in a class who are obese relative to the presence at .25 ...