Environmental Menu Labels and Food Selection Among US Adults: A Randomized Clinical Trial.

Abstract

Food systems account for approximately one-third of global greenhouse gas emissions (GHGE), and many foods with high GHGE pose risks to human health. Environmental impact (eg, climate) labels on restaurant menus may promote lower GHGE and higher nutritional quality food choices. To compare the efficacy of climate labels on the GHGE and nutritional quality of food choices. This online randomized clinical trial was conducted using a menu based on a US fast food chain between December 2024 and February 2025. Participants included US adults aged 18 years or older. Analyses were conducted between February and April 2025. Participants were randomized to 1 of 6 label conditions: (1) control, (2) environmental cost (GHGE represented as a monetary cost), (3) climate grade (GHGE represented as a grade [eg, A to F, with A representing the lowest GHGE]), (4) climate grade plus scale (GHGE represented as a grade accompanied by a scale showing all possible grades), (5) high climate impact on items with high GHGE, and (6) warning high climate impact on items with high GHGE. Participants ordered from a fast food menu displaying their assigned label next to applicable items. Primary outcomes include the selection of an item with high climate impact and GHGE of menu orders. Secondary outcomes include Nutrient Profile Index (NPI) score and nutrients of menu orders and participant perceptions. This study included 10 342 participants (mean [SD] age: 46.4 [16.9] years; 53% women). Participants in the climate grade (825 of 1721 [48%]; P = .02), climate grade plus scale (787 of 1719 [46%]; P < .001), high climate impact (777 of 1724 [45%]; P < .001), and warning high climate impact (817 of 1725 [47%]; P = .01) conditions were significantly less likely to select an item with a high climate impact than those in the control condition (920 of 1728 [53%]). Participants in the climate grade plus scale (mean GHGE, 16.3 [95% CI, 15.5-17.2] kg CO2 equivalent, adjusted P < .001) and high climate impact (mean GHGE, 16.9 [95% CI, 16.0-17.8] kg CO2 equivalent, adjusted P = .04) conditions selected items with lower GHGE than those in the control condition (mean GHGE, 18.8 [95% CI, 17.9-19.6] kg CO2 equivalent). NPI scores did not differ among label conditions, but participants in the climate grade plus scale condition selected items with less saturated fat than those in the control condition (11.8 g vs 12.6 g; adjusted P = .04). Although there were no significant differences between the environmental cost and control labels for primary or secondary nutrition outcomes, when viewing labels in isolation, participants perceived the environmental cost label as the most discouraging of selecting high climate impact items (mean score, 3.0 [95% CI, 2.9-3.1]; P < .001). This randomized clinical trial's findings suggest that using climate labels on restaurant menus, particularly climate grade plus scale designs, may decrease climate impact and improve nutrition of restaurant orders. Future research is needed on environmental cost label designs and climate label use in real restaurant settings. ClinicalTrials.gov Identifier: NCT06651060.