OBJECTIVE: Food packaging often pictures supplementary extras, such as toppings or frosting, that are not listed on the nutritional labelling. The present study aimed to assess if these extras might exaggerate how many calories are pictured and if they lead consumers to overserve.DESIGN: Four studies were conducted in the context of fifty-one different cake mixes. For these cake mixes, Study 1 compared the calories stated on the nutrition label with the calories of the cake (and frosting) pictured on the box. In Studies 2, 3 and 4, undergraduates (Studies 2 and 3) or food-service professionals (Study 4) were given one of these typical cake mix boxes, with some being told that cake frosting was not included on the nutritional labelling whereas others were provided with no additional information. They were then asked to indicate what they believed to be a reasonable serving size of cake. Settings Laboratory setting.SUBJECTS: Undergraduate students and food-service professionals.RESULTS: Study 1 showed that the average calories of cake and frosting pictured on the package of fifty-one different cake mixes exceed the calories on the nutritional label by 134 %. Studies 2 and 3 showed that informing consumers that the nutritional information does not include frosting reduces how much people serve. Study 4 showed that even food-service professionals overserve if not told that frosting is not included on the nutritional labelling.CONCLUSIONS: To be less misleading, packaging should either not depict extras in its pictures or it should more boldly and clearly state that extras are not included in calorie counts.