Effects of social interaction, physical environment and food choice freedom on consumption in a meal-testing environment.

Consumption of pizza, salad and iced tea was assessed in four separate tests at a central location. Three aspects of context were added in successive tests-social interaction during consumption, the physical environment in which the food was consumed and choice among foods-so that the fourth test had all effects present. The proportion consumed averaged from 79 to 82% of the food presented and increased significantly in the presence of one or more of the context manipulations. Salad consumption was higher when there was a choice of dressings in an enhanced environment. Pizza and tea consumption were higher in an enhanced restaurant-like environment. Social interaction alone has no detectable impact on food consumption. It is concluded that people eat more in enhanced contexts and careful consideration should be given to the environment in studies of food consumption.