People are getting fat. The rise in obesity rate has been particularly pronounced in the United States since the middle of the 1970s, but has by now extended into many other areas of the world. Several sources of technological change have been singled out as potential explanations for why people have been gaining so much weight. Increased productivity in agriculture has lowered the relative price of food (Darius Lakdwalla, Tomas Philipson, and Jayanta Bhattacharya 2005) while innovations in food processing have reduced the time cost of preparing food (David M. Cutler, Edward L. Glaeser, and Jesse M. Shapiro 2003). Technological change has also affected how people spend their time, in a way that may systematically have reduced calories expended. First, physically less demanding jobs in the service sector have replaced physically more demanding jobs in agriculture and manu facturing. Second, the allocation of time across different activities has changed dramatically over the last few decades: people are spending less time working (decline in labor market work for men, decline in home production work for women) and more time in mainly sedentary forms of leisure, such as watching TV (Mark Aguiar and Erik Hurst 2007). While the focus so far has been on the rela tionship between how people spend their time and how many calories they expend, we argue in this piece that there might also be an inter esting relationship between how people spend their time and how many calories they consume. Motivating this question is a (at first glance) rather counterintuitive finding from the time use surveys: the fact that people, in the United States