Discussion of a "Goldman Tax" on banks often includes mention of "moral hazard," the idea that banks will take more reckless risks if they know they can count on a bailout. A new paper from the National Bureau of Economic Research, provocatively headlined "Does Health Insurance Make You Fat?" demonstrates how moral hazard operates on an individual level. Economists find "stronger evidence" that having health insurance increases obesity. If you know that your insurance will pay for that bypass operation or diabetes medicine, why skip that second dessert? It'd be interesting to see research on how having health insurance (or life insurance) affects other behavior that poses health risks -- say, smoking, or riding a motorcycle without a helmet.