In response to increasing rates of obesity, many dining establishments have focused on promoting the health properties and benefits of nutritious foods to encourage people to choose healthier options.1 Ironically however, health-focused labeling of food may be counter-effective, as people rate foods that they perceive to be healthier as less tasty.2 Healthy labeling is even associated with higher hunger hormone levels after consuming a meal compared with when the same meal is labeled indulgently.3 How can we make healthy foods just as appealing as more classically indulgent and unhealthy foods? Because healthy foods are routinely labeled with fewer appealing descriptors than standard foods,1 this study tested whether labeling vegetables with the flavorful, exciting, and indulgent descriptors typically reserved for less healthy foods could increase vegetable consumption.
The study was conducted in a large university cafeteria serving a mean (SD) 607 (52) diners per weekday lunch (52.5% undergraduate students, 32.5% graduate students, 15.1% staff/other). The Stanford University institutional review board approved this study and waived informed consent. Data were collected each weekday for the 2016 autumn academic quarter (n = 46 days). Each day, one featured vegetable was randomly labeled in 1 of 4 ways: basic, healthy restrictive, healthy positive, or indulgent (Table). No changes were made to how the vegetables were prepared or served. Each day research assistants discretely recorded the number of diners selecting the vegetable and weighed the mass of vegetables taken from the serving bowl. We predicted that vegetables labeled with indulgent descriptors would be chosen more than the same vegetables labeled with basic or healthy descriptors. Means were compared using analysis of variance.
During the study period, 8279 of 27 933 total diners selected the vegetable (29.6%). Labeling had a significant effect on both the number of diners selecting the vegetable (F3,42 = 2.83; P = .05) and the mass of vegetables consumed (F3,42 = 4.29; P = .01). Pairwise comparisons (Figure) revealed that labeling vegetables indulgently resulted in 25% more people selecting the vegetable than in the basic condition (95% CI, 1%-49%; P = .04), 41% more people than in the healthy restrictive condition (95% CI, 18%-64%; P = .001), and 35% more people than in the healthy positive condition (95% CI, 10%-60%; P = .01). Similarly, labeling vegetables indulgently resulted in a 23% increase in mass of vegetables consumed compared with the basic condition (95% CI, 3%-43%; P = .03) and a 33% increase in mass of vegetables consumed compared with the healthy restrictive condition (95% CI, 11%-53%; P = .004), but a nonsignificant 16% increase in mass consumed compared with the healthy positive condition (95% CI, −5% to 36%; P = .14). There were no significant differences among the basic, healthy restrictive, and healthy positive conditions for either outcome (P > .25 for all).
Labeling vegetables with indulgent descriptors significantly increased the number of people choosing vegetables and the total mass of vegetables consumed compared with basic or healthy descriptions, despite no changes in vegetable preparation. These results challenge existing solutions that aim to promote healthy eating by highlighting health properties or benefits and extend previous research that used other creative labeling strategies, such as using superhero characters, to promote vegetable consumption in children.4,5 Our results represent a robust, applicable strategy for increasing vegetable consumption in adults: using the same indulgent, exciting, and delicious descriptors as more popular, albeit less healthy, foods. This novel, low-cost intervention could easily be implemented in cafeterias, restaurants, and consumer products to increase selection of healthier options. Though we were unable to measure how much food was eaten by patrons individually, people generally eat 92% of self-served food, regardless of portion size and food type.6 Further research should assess how well the effects generalize to other settings and explore the potential of indulgent labeling to help alleviate the pervasive cultural mindset that healthy foods are not tasty.1-3
Corresponding Author: Bradley P. Turnwald, MS, Stanford University, Bldg 420, Jordan Hall, Rm 384, Stanford, CA 94305-2130 (firstname.lastname@example.org).
Accepted for Publication: March 27, 2017.
Correction: This article was corrected on July 24, 2017, to correct 2 P values that were switched in the Results section.
Published Online: June 12, 2017. doi:10.1001/jamainternmed.2017.1637
Author Contributions: Mr Turnwald had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: All authors.
Acquisition, analysis, or interpretation of data: Turnwald, Boles.
Drafting of the manuscript: Turnwald.
Critical revision of the manuscript for important intellectual content: All authors.
Statistical analysis: Turnwald.
Administrative, technical, or material support: Boles.
Study supervision: Crum.
Conflict of Interest Disclosures: None reported.
Funding/Support: This material is based upon work supported by the Robert Wood Johnson Foundation and the National Science Foundation Graduate Research Fellowship Program (grant No. DGE-114747).
Role of the Funder/Sponsor: 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; and decision to submit the manuscript for publication.
Additional Contributions: We wish to acknowledge the Stanford Residential & Dining Enterprises team at Stanford University for assisting study design and implementation, particularly Jackie Bertoldo, MPH, RDN; Eric Montell, Executive Director; and Shirley J. Everett, EdD, MBA. We also thank research assistants Rina Horii, Katie Wolfteich, Inbar Kodesh, Felicia Schuessler, Cole Fiers, and Meg McNulty for assisting with data collection. None of the contributors received compensation for their work.
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