Since the mid-1970s, obesity has rapidly increased among people in the U.S. Secondary eating is one factor blamed for obesity. Secondary eating is defined as eating while doing something else such as reading or watching TV. We hypothesize that lifestyle is an important moderator of the effect of secondary eating on obesity. Using data from the 2006-8 American Time Use Survey (ATUS), the results indicate that a sedentary lifestyle increases the odds of mindless secondary eating, leading to overeating and obesity.