This article assesses the nature of the connection between restaurants and obesity by exploiting variation in the supply of restaurants and examining the impact on consumers’ body mass. To serve the large market of highway travelers, a disproportionate number of restaurants locate immediately adjacent to highways. For residents of highway communities, the highway boosts the supply of restaurants in a manner that is plausibly uncorrelated with demand or general health practices. To uncover the causal effect of restaurants on obesity, this article compares the prevalence of obesity in communities located immediately adjacent to interstate highways with the prevalence of obesity in communities located slightly farther away. This article finds that restaurant access and restaurant consumption have no significant effects on obesity. Detailed analyses of food intake data reveal that, although restaurant meals are associated with greater caloric intake, many of these additional calories are offset by reductions in eating throughout the rest of the day. This article also finds evidence of selection - individuals that frequent restaurants also eat more when they eat at home.