Are Restaurants Really Supersizing America?
利用州际公路在农村地区的布局作为工具变量，研究发现餐馆消费与肥胖之间没有因果关系，消费者会通过在其他时间少吃来抵消餐馆摄入的卡路里，因此针对餐馆的监管不太可能减少肥胖，反而可能损害消费者福利。
While many researchers and policymakers infer from correlations between eating out and body weight that restaurants are a leading cause of obesity, a basic identification problem challenges these conclusions. We exploit the placement of Interstate Highways in rural areas to obtain exogenous variation in the effective price of restaurants and examine the impact on body mass. We find no causal link between restaurant consumption and obesity. Analysis of food-intake micro-data suggests that consumers offset calories from restaurant meals by eating less at other times. We conclude that regulation targeting restaurants is unlikely to reduce obesity but could decrease consumer welfare.