The effect of ingredient-specific calorie information on calories ordered

Providing calorie labeling is a widely used strategy to combat obesity. However, there is little evidence that the availability of calorie information at food-away-from-home establishments has an effect on food choices. Listing calorie information for each ingredient, though, may allow customers to avoid high-calorie items that add little to their enjoyment. Data from a natural experiment were used to compare total calories ordered before and after the provision of per-ingredient versus for build-your-own sandwiches, and per-sandwich for pre-defined sandwiches, at a supermarket sandwich counter. Sandwich order slips from a Lincoln, Neb. supermarket were collected from December 15, 2016 to February 4, 2018. In June 2017, calorie information was introduced. A total of 1134 build-your-own orders and 559 pre-defined orders were collected. Calories ordered before and after the provision of calorie information were examined for build-your-own and pre-defined sandwiches using two-sample t-tests. Orders post-calorie information were split into three periods to examine whether responses to information changed over time. Ingredients ordered were also examined before and after information was provided. Customers decrease calories ordered by 7.8% for build-your-own sandwiches when per-ingredient calorie information is introduced. There is no significant change in calories ordered for pre-defined sandwiches. Calorie reduction appears to result from substitution away from some higher calorie items, e.g., mayonnaise, towards lower calorie ingredients, like mustard. Despite low calorie content, customers did not increase the number of vegetables ordered. Finally, there is no attenuation of the effect of calorie information over time.