Food Prices and Body Fatness among Youths
In this paper, we examine the effect of food prices on clinical measures of obesity, including body mass index (BMI) and percentage body fat (PBF) measures derived from bioelectrical impedance analysis (BIA) and dual energy x-ray absorptiometry (DXA), among youths ages 12 through 18. The empirical analyses employ data from various waves of the National Health and Nutrition Examination Survey (NHANES) merged with several food prices measured by county and year. This is the first study to consider clinically measured levels of body composition rather than BMI to investigate the effects of food prices on obesity among youths. We also examine whether the effects of food prices on body composition differ by gender and race/ethnicity. Our findings suggest that increases in the real price of one calorie in food for home consumption and the real price of fast-food restaurant food lead to improvements in obesity outcomes among youths. We also find that an increase in the real price of fruits and vegetables has negative consequences for these outcomes. Finally, our results indicate that measures of PBF derived from BIA and DXA are no less sensitive and in some cases more sensitive to the prices just mentioned than BMI.
Research for this paper was supported by grant #65068 from the Robert Wood Johnson Foundation to the National Bureau of Economic Research. This paper was presented at the Eighth World Congress of the International Health Economics Association and at the Sixth Annual Meeting of the Robert Wood Johnson Foundation Healthy Eating Research Program. We are grateful to John Cawley who discussed our paper at the first forum just mentioned, to the other participants in both forums, and to Jesse Margolis for helpful comments and suggestions. We also wish to thank Jesse, Ryan Conrad, and Ben Padd for research assistance. We are indebted to Karen Davis, formerly a health scientist at the National Center for Health Statistics Research Data Center (RDC); Stephanie Robinson, a health scientist at the NCHS RDC; Frances McCarty, a senior service research fellow at the NCHS RDC; and Frank Limehouse, RDC Administrator at the Chicago Bureau of the Census RDC, for their assistance in helping us to gain access to and work with restricted files from the National Health and Nutrition Examination Survey at the Chicago RDC. The views expressed herein are those of the authors and do not necessarily reflect the views of the National Bureau of Economic Research.