In the first part of the study, a trained research assistant asked the diners to estimate the number of calories in the meal that they had just consumed. While the diner was answering the questions, the researcher counted the number of each type of food container and wrapper on the person's tray. The restaurant provides the calorie content of each food item on its Web site, so the researcher could calculate the actual calorie content of the meal. In the second part of the study, the researchers displayed 15 different meals purchased at a fast-food restaurant and asked the participants to guess the number of calories in each meal. The actual calorie content varied from 445 to 1780 calories. In both studies, the researchers asked the participants to give their height and weight.