Evaluating the effect of mandatory kilocalorie labelling on energy consumed in the out-of-home food sector: a pre vs. post-implementation observational study in England

Objectives: In April 2022, mandatory kilocalorie (kcal) labelling in the out-of-home food sector (OHFS) was introduced as a policy to reduce obesity in England. The legislation required food outlets belonging to large (>250 employees) businesses in England selling food for immediate consumption to provide kcal labelling on all unpackaged food and non-alcoholic drinks. We examined whether the implementation of this policy was associated with a change in consumer behaviour in the OHFS. Design: Observational study.Setting: OHFS outlets subject to the policy in four areas of England. Participants: From August-December 2021 (pre-implementation) and August-December 2022 (post-implementation), researchers visited the same large OHFS outlets subject to kcal labelling legislation and conducted customer exit surveys. 6578 customers (3308 pre-implementation and 3270 post-implementation) from 330 outlets were surveyed. Main outcome measures: The number of kcals purchased and consumed by customers, customers' knowledge of the kcal content of their purchases, and the extent to which customers noticed and used kcal labelling. Results: At baseline, mean energy purchased (mean, M=1007 kcals, SD = 630) and consumed (M=909 kcals, SD = 548) per customer was high compared to national guidance. There were no changes in energy purchased pre vs. post-implementation (difference pre vs. post, B = 11.31, [95% CI: -27.15 to 49.77], p= 0.564) or consumed (B=18.51, [95% CI: -15.01 to 52.03], p= 0.279) for adjusted findings. Post-implementation, participants underestimated the energy content of their purchased meal less (B = 61.21, [95% CI: 21.57 to 100.86], p<0.001), were more likely to report noticing (odds ratio, OR post vs. pre = 2.25 [95% CI: 1.84 to 2.73], p<0.001) and using of kcal labelling (OR = 2.15 [95% CI: 1.62 to 2.85], p <0.001) compared to pre-implementation. Conclusions: The introduction of the mandatory kcal labelling policy in England was not associated with a significant decrease in the number of kcals purchased or consumed in OHFS outlets. Although a lack of compliance with labelling legislation found in previous research may have contributed to the lack of change in energy purchased and consumed observed in the present study. Improved accuracy of meal energy estimations and increased reporting of noticing and use of kcal labelling were observed and this may have wider public health implications. Registration: Study protocol and analysis strategy pre-registered on Open Science Framework (https://osf.io/pfnm6/).