A Natural Experiment to Evaluate the Nutritional Content of Restaurant Meal Purchases After Calorie Labeling

Abstract

Background: Calorie labeling is mandated in restaurant chains with ≥20 locations nationwide, but the effect of labeling on the nutritional quality of purchased meals in fast-food settings is unclear, especially for adolescents and children.

Objective: To estimate the effect of calorie menu labeling on the nutrient content and composition of fast-food meal purchases in McDonald's restaurants vs control restaurants.

Design: From 2010 to 2014, customers were sampled during repeated visits to McDonald's restaurants, which voluntarily labeled menus with calorie information in 2012, and 5 control fast-food restaurant chains that had not labeled their menus over the study period.

Participants/setting: Restaurant receipts and questionnaires were collected from 2883 adults, 2131 adolescents, and 433 children in 4 New England cities.

Main outcome measures: Saturated fat, sugar, sodium, and fiber content of purchased meals, as well as nutrient densities (ie, nutrient content adjusted for total calories), were calculated after linking purchases to nutrition data from restaurant websites.

Statistical analyses: Difference-in-differences analyses and linear mixed models were used to examine whether calorie labeling in McDonald's was associated with changes in nutrient content and nutrient density of purchased meals separately in adults, adolescents, and children.

Results: After implementation of calorie labeling at McDonald's, adult meals contained on average 4.0% fewer calories from sugar (95% confidence interval: -7.5 to -0.5), but 1.8% more calories from saturated fat (95% confidence interval: 0.7 to 2.9) compared with control chains. The fiber content of children's purchased meals was lower at McDonald's after calorie labeling (change = -1.4 g, 95% confidence interval: -2.5 to -0.3). Calorie labeling was not associated with changes in nutrient quality of adolescent meals.

Conclusions: Calorie labeling at McDonald's was associated with a possibly small positive change in the nutritional quality of meals in adults but not in adolescents or children. Efforts are needed to improve the nutritional quality of restaurant meals.

Keywords: Calorie labeling; Diet quality; Natural experiment; Nutrients; Obesity prevention.