Has Overweight Become the New Normal? Evidence of a Generational Shift in Body Weight Norms

We test for differences across the two most recent NHANES survey periods (1988–1994 and 1999– 2004) in self-perception of weight status. We find that the probability of self-classifying as overweight is significantly lower on average in the more recent survey, for both men and women, controlling for objective weight status and other factors. Among women, the decline in the tendency to self-classify as overweight is concentrated in the 17–35 age range, and, within this range, is more pronounced among women with normal BMI than among those with overweight BMI. Among men, the shift away from feeling overweight is roughly equal across age groups, except that the oldest group (56–74) exhibits no difference between surveys. In addition, overweight men exhibit a sharper decline in feeling overweight than normal-weight men. Despite the declines in feeling overweight between surveys, weight misperception did not increase significantly for men and decreased by a sizable margin among women. The shifts in selfclassification are not explained by differences between surveys in body fatness or waist circumference, nor by shifting demographics. We interpret the findings as evidence of a generational shift in social norms related to body weight, and propose various mechanisms to explain such a shift, including: (1) higher average adult BMI and adult obesity rates in the later survey cohort, (2) higher childhood obesity rates in the later survey cohort, and (3) public education campaigns promoting healthy body image. The welfare implications of the observed trends in self-classification are mixed. JEL Classifications: I10, J11, Z13 Mary A. Burke is a senior economist at the Federal Reserve Bank of Boston, Frank Heiland is an assistant professor of economics at Florida State University, and Carl Nadler is a senior research assistant at the Federal Reserve Bank of Boston. Their email addresses are [email protected], [email protected], and [email protected], respectively. This paper, which may be revised, is available on the web site of the Federal Reserve Bank of Boston at http://www.bos.frb.org/economic/wp/index.htm. The views expressed in this paper are those of the authors and do not necessarily represent those of the Federal Reserve Bank of Boston or the Federal Reserve System. The authors would like to acknowledge the helpful feedback of Rusty Tchernis, Gerhard Glomm, and other participants at the Indiana University conference, “Cognitive, Behavioral, and Economic Approaches to Adolescent and Childhood Obesity,” September 4–5, 2008. This version: April 8, 2009