Is there an obesity externality? In the late 1990s and early 2000s, many state governments began requiring health insurance plans to cover treatments for diabetes. Using difference-in-difference analysis of restricted geocode data from the 1979 National Longitudinal Survey of Youth to compare wages across states with and without diabetes mandates, I find that obese people pay for all of their own increased health costs in the form of lower wages, rather than passing them on to employers, insurers, and co-workers.