"Rational overeating" in a feast-or-famine world: Economic insecurity and the obesity epidemic

Obesity has risen dramatically in the United States since the 1980s, but incidence varies across demographic groups. We investigate the potential role of economic insecurity-defined, roughly, as the extent to which a household faces the threat of catastrophic income loss-in explaining these changes. We construct a synthetic panel of demographic groups for 1988-2016 by combining the Economic Security Index (which measures the probability of a year-on-year drop in adjusted household income of 25% or more) with data from the NHANES surveys. This gives us a plausibly exogenous group-level measure of economic insecurity while allowing us to control for both individual characteristics and various interactions of group and year fixed effects. We find robust evidence of a link between economic insecurity and obesity, suggesting a nearly one-to-one correspondence in percentage point changes in ESI and obesity, for both men and women. We further show that if we instead measure economic insecurity based on the changing occupational exposure of each demographic group to trade with China over time, we find similar qualitative results for men, but not for women. Taken together, these results are supportive of a causal interpretation of our findings.