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Estimating the effect of calorie menu labeling on calories purchased in a large restaurant franchise in the southern United States: quasi-experimental study

BMJ 2019; 367 doi: https://doi.org/10.1136/bmj.l5837 (Published 30 October 2019) Cite this as: BMJ 2019;367:l5837

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Calorie labelling to reduce obesity

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Fostering academic-retail partnerships to evaluate nutrition policies

  1. Joshua Petimar, postdoctoral research fellow12,
  2. Fang Zhang, assistant professor3,
  3. Lauren P Cleveland, research associate2,
  4. Denise Simon, project manager2,
  5. Steven L Gortmaker, professor4,
  6. Michele Polacsek, professor5,
  7. Sara N Bleich, professor6,
  8. Eric B Rimm, professor17,
  9. Christina A Roberto, assistant professor8,
  10. Jason P Block, associate professor2
  1. 1Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
  2. 2Division of Chronic Disease Research Across the Lifecourse, Department of Population Medicine, Harvard Pilgrim Health Care Institute and Harvard Medical School, Boston, MA, USA
  3. 3Division of Health Policy and Insurance Research, Department of Population Medicine, Harvard Pilgrim Health Care Institute and Harvard Medical School, Boston, MA, USA
  4. 4Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health, Boston, MA, USA
  5. 5Westbrook College of Health Professions, University of New England, Portland, ME, USA
  6. 6Department of Health Policy and Management, Harvard T.H. Chan School of Public Health, Boston, MA, USA
  7. 7Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, USA
  8. 8Department of Medical Ethics and Health Policy, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
  1. Correspondence to: J Petimar jsp778{at}mail.harvard.edu
  • Accepted 24 September 2019

Abstract

Objective To evaluate whether calorie labeling of menus in large restaurant chains was associated with a change in mean calories purchased per transaction.

Design Quasi-experimental longitudinal study.

Setting Large franchise of a national fast food company with three different restaurant chains located in the southern United States (Louisiana, Texas, and Mississippi) from April 2015 until April 2018.

Participants 104 restaurants with calorie information added to in-store and drive-thru menus in April 2017 and with weekly aggregated sales data during the pre-labeling (April 2015 to April 2017) and post-labeling (April 2017 to April 2018) implementation period.

Main outcome measures Primary outcome was the overall level and trend changes in mean purchased calories per transaction after implementation of calorie labeling compared with the counterfactual (ie, assumption that the pre-intervention trend would have persisted had the intervention not occurred) using interrupted time series analyses with linear mixed models. Secondary outcomes were by item category (entrees, sides, and sugar sweetened beverages). Subgroup analyses estimated the effect of calorie labeling in stratums defined by the sociodemographic characteristics of restaurant census tracts (defined region for taking census).

Results The analytic sample comprised 14 352 restaurant weeks. Over three years and among 104 restaurants, 49 062 440 transactions took place and 242 726 953 items were purchased. After labeling implementation, a level decrease was observed of 60 calories/transaction (95% confidence interval 48 to 72; about 4%), followed by an increasing trend of 0.71 calories/transaction/week (95% confidence interval 0.51 to 0.92) independent of the baseline trend over the year after implementation. These results were generally robust to different analytic assumptions in sensitivity analyses. The level decrease and post-implementation trend change were stronger for sides than for entrees or sugar sweetened beverages. The level decrease was similar between census tracts with higher and lower median income, but the post-implementation trend in calories per transaction was higher in low income (change in calories/transaction/week 0.94, 95% confidence interval 0.67 to 1.21) than in high income census tracts (0.50, 0.19 to 0.81).

Conclusions A small decrease in mean calories purchased per transaction was observed after implementation of calorie labeling in a large franchise of fast food restaurants. This reduction diminished over one year of follow-up.

Footnotes

  • Contributors: JP curated and analyzed the data and wrote the manuscript. JPB conceptualized and designed the study and acquired the data. FZ provided statistical expertise. LPC and DS assisted in data management. All authors aided in interpretation of results and read and approved the final version for submission. JP and JPB have full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis; they are the guarantors. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

  • Funding: This study was funded by R01DK115492 from the National Institutes of Health awarded to JPB. JP is supported by T32HL098048 from the National Heart, Lung, and Blood Institute. The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; or the decision to submit the manuscript for publication. We confirm the independence of researchers from funders and that all authors, external and internal, had full access to all of the data (including statistical reports and tables) in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis. Dissemination of the results to study participants and patient organizations is not possible.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: funding from the National Institutes of Health (R01DK115492 to JPB) and the National Heart, Lung, and Blood Institute (T32HL098048 to JP); no financial relationships with any organizations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: This study was approved by the institutional review board of Harvard Pilgrim Health Care (protocol No 1172690-2).

  • Data sharing: No additional data available

  • The lead authors (JP and JPB) affirm that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.

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