In the latest podcast EconTalk, Darius Lakdawalla and I discuss just how much fatter Americans are than they once were and why. Turns out, it’s not McDonald’s fault. We also discuss the role of norms, the changing nature of the workforce, the technology of barbecue potato chips. He has a very nice insight that in the past, we were paid to exercise on the job and now we pay for the opportunity to exercise. Listen to it here.