Restaurant foods are typically higher in calories than meals consumed at home. A goal of the 2010 Patient Protection and Affordable Care Act is to encourage healthier food choices at restaurants by providing consumers with information about the calorie content of menu items. However, doesn't a well-informed consumer already know that a 12-piece bucket of chicken has more calories than a salad? Following research in marketing science and behavioral economics, we evaluate a representative consumer's ability to discriminate between low-calorie and high-calorie menu items using only some basic "rules of thumb" nutrition knowledge. Results reveal the extent to which menu labeling may increase consumers' knowledge about the calories in restaurant foods. © 2015 by Wiley Periodicals, Inc.