This paper examines the assumptions that consumers know how many calories they should consume throughout the course of a day and customers improperly estimate the number of calories in their fast food order. It then examines whether mandatory menu labeling influences either of these assumptions. Based on receipt and survey data collected from consumers outside fast food restaurants in lower-income communities in New York City, researchers found that one-third of consumers properly estimated the number of calories an adult should consume in a day; menu labeling did not change these findings. Menu labeling did increase the number of consumers who correctly estimated the number of calories in their fast food meal, from 15% before menu labeling to 24% after menu labeling.