Deprivation or Discrimination? Comparing Theories of the Reverse Income-Obesity Gradient in the U.S. and South Korea
In high-income countries, poverty is often associated with higher average body mass index (BMI). To account for this reverse gradient, deprivation theories posit that declining economic resources make it more difficult to maintain a healthy weight. By contrast, discrimination theories argue that anti-fat discrimination in hiring and marriage sorts heavier individuals into lower-income households. We assess competing predictions of these theories by examining how household income in representative samples from South Korea (2007–2014, N=20,823) and the U.S. (1999–2014, N=6,395) is related to BMI in two key contrasting groups: (1) currently married and (2) never married individuals. Naïve analyses that aggregate these two groups reveal the well-established reverse gradient. Stratified analyses, on the other hand, reveal that the gradient only appears among currently married women, but not never-married women or men. Further analyses indicated that these differences in the gradient by marital status cannot be accounted for a number of alternative hypothesis based on differential employment or motivation to lose weight. Though consistent with predictions of anti-fat discrimination in marriage, these findings raise important challenges to deprivation theories of the reverse gradient.