Effect of calories-only vs physical activity calorie expenditure labeling on lunch calories purchased in worksite cafeterias

Background Calorie labeling on restaurant menus is a public health strategy to guide consumer ordering behaviors, but effects on calories purchased have been minimal. Displaying labels communicating the physical activity required to burn calories may be a more effective approach, but real-world comparisons are needed. Methods In a quasi-experimental study, we examined the effect of physical activity calorie expenditure (PACE) food labels compared to calorie-only labels on point-of-decision food purchasing in three worksite cafeterias in North Carolina. After a year of quarterly baseline data collection, one cafeteria prominently displayed PACE labels, and two cafeterias prominently displayed calorie-only labels. Calories from foods purchased in the cafeteria during lunch were assessed over 2 weeks every 3 months for 2 years by photographs of meals. We compared differences in purchased calorie estimates before and after the labeling intervention was introduced using longitudinal generalized linear mixed model regressions that included a random intercept for each participant. Results In unadjusted models comparing average meal calories after vs before labeling, participants exposed to PACE labels purchased 40.4 fewer calories ( P = 0.002), and participants exposed to calorie-only labels purchased 38.2 fewer calories ( P = 0.0002). The small difference of 2 fewer calories purchased among participants exposed to PACE labeling vs calorie-only labeling was not significant ( P = 0.90). Models adjusting for age, sex, race, occupation, numeracy level, and health literacy level did not change estimates appreciably. Conclusion In this workplace cafeteria setting, PACE labeling was no more effective than calorie-only labeling in reducing lunchtime calories purchased.