TY - JOUR AU - Bhattacharya,Jay AU - Bundorf,Kate AU - Pace,Noemi AU - Sood,Neeraj TI - Does Health Insurance Make You Fat? JF - National Bureau of Economic Research Working Paper Series VL - No. 15163 PY - 2009 Y2 - July 2009 UR - http://www.nber.org/papers/w15163 L1 - http://www.nber.org/papers/w15163.pdf N1 - Author contact info: Jay Bhattacharya 117 Encina Commons Center for Primary Care and Outcomes Research Stanford University Stanford, CA 94305-6019 Tel: 650/736-0404 Fax: 650/723-1919 E-Mail: jay@stanford.edu Kate Bundorf Health Research and Policy Stanford University HRP T108 Stanford, CA 94305-5405 Tel: 650/725-0067 Fax: 650/725-6951 E-Mail: bundorf@stanford.edu Noemi Pace University College London Centre for International Health and Development 30 Guilford Street London WC1N 1EH E-Mail: n.pace@ucl.ac.uk Neeraj Sood Department of Clinical Pharmacy USC School of Pharmacy 1985 Zonal Avenue Los Angeles, CA 90033 Tel: 310/393-0411 Fax: 310/260-8156 E-Mail: nsood@usc.edu M1 - published as Jay Bhattacharya, M. Kate Bundorf, Noemi Pace, Neeraj Sood. "Does Health Insurance Make You Fat?," in Michael Grossman and Naci H. Mocan, editors, "Economic Aspects of Obesity" University of Chicago Press (2011) AB - The prevalence of obesity has been rising dramatically in the U.S., leading to poor health and rising health care expenditures. The role of policy in addressing rising rates of obesity, however, is controversial. Policy recommendations for interventions intended to influence body weight decisions often assume the obesity creates negative externalities for the non-obese. We build on earlier work demonstrating that this argument depends on two important assumptions: 1) that the obese do not pay for their higher medical expenditures through differential payments for health care and health insurance, and 2) that body weight decisions are responsive to the incidence of medical care costs associated with obesity. In this paper, we test the latter proposition – that body weight is influenced by insurance coverage - using two approaches. First, we use data from the Rand Health Insurance Experiment, in which people were randomly assigned to varying levels of health insurance, to examine the effect of generosity of insurance coverage on body weight along the intensive coverage margin. Second, we use instrumental variables methods to estimate the effect of type of insurance coverage (private, public and none) on body weight along the extensive margin. We explicitly address the discrete nature of the endogenous indicator of health insurance coverage by estimating a nonlinear instrumental variables model. We find weak evidence that more generous insurance coverage increases body mass index. We find stronger evidence that being insured increases body mass index and obesity. ER -