• Sophia V Hua, Erica L Kenney, Jeffrey M Miller, Aviva A Musicus, Christina A Roberto, Anne N Thorndike, and Eric B Rimm.
• Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, Massachusetts. Electronic address: sophiahua@fas.harvard.edu.
• Am J Prev Med. 2023 Jun 1; 64 (6): 805813805-813.

IntroductionLarge portions, which can lead people to eat more, are becoming increasingly common in U.S. restaurants. This study tested whether portion-size descriptions on menus and different pricing strategies influence the selection of smaller portion sizes.Study DesignThis was a 4 × 2 between-subjects online randomized controlled experiment.Setting/ParticipantsThis was an online simulated menu-ordering study conducted in 2021 among 2,205 U.S. adults.InterventionAdults viewed a fast-casual and full-service menu with entrées available in 2 sizes and ordered an entrée from each. Participants were randomized to view 1 of 4 portion-size descriptors (smaller/larger portion): (1) no descriptor/large (control), (2) standard/large, (3) just right/large, and (4) no descriptor/hearty. Participants were also randomized to either linear (i.e., reduced price=50% larger portion's price) or nonlinear pricing (i.e., reduced price=70% larger portion's price) (4 × 2 factorial design).Main Outcome MeasuresIn 2022, logistic regression models were used to analyze whether the interventions increased the likelihood of choosing a reduced portion.ResultsRegardless of pricing scheme, participants in the standard/large condition selected reduced portions by 10 (95% CI=0.04, 0.16) and 13 (95% CI=0.07, 0.18) percentage points more than those in the control condition (fast-casual and full-service menus, respectively). Selection of reduced portions in the just right/large condition increased by 9 (95% CI=0.04, 0.15) and 8 (95% CI=0.02, 0.14) percentage points. For the fast-casual menu, keeping portion-size descriptors constant, participants ordered a reduced portion by 5 percentage points more with nonlinear pricing than with linear pricing.ConclusionsPortion-size descriptions on restaurant menus, even with nonlinear pricing, are a low-cost strategy to promote the selection of lower-calorie, smaller portions without restricting choice.Copyright © 2023 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

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