People eating at fast-food restaurants underestimate the calorie content of meals. This was particularly true with large meals, according to a survey of diners at six restaurant chains. The cross-sectional survey included 1,877 adults, 1,178 adolescents, and 330 school-age children in four New England cities. The restaurants didn't include calorie counts on their menus but provided nutrition information on posters and elsewhere. At least two-thirds of all participants underestimated the calories of their meals, a quarter by 500 calories or more. The larger the meal, the greater the underestimation. Noticing the posted calorie information did not affect the accuracy of calorie estimations. The report appeared online May 23 in BMJ.