Eco-Focused Menu Labels on Full Meal Orders From Fast-Food Restaurants: A Randomized Clinical Trial.

Importance: Promoting environmentally sustainable dietary patterns can benefit both population and planetary health. Ecolabels on restaurant menus could promote healthful and sustainable choices, but evidence is needed on effects in different restaurant types. Objective: To test the effects of different ecolabel designs on menus from 2 fast-food restaurants on the healthfulness of full meal orders, compared to a control label. Design, Setting, and Participants: This randomized clinical trial was conducted online in a nationally representative sample of adults (≥18 years) in the US in April 2025. Participants were recruited from the NORC AmeriSpeak survey panel to participate in this experiment. Intervention: Participants were randomized via an automated process within the survey platform to 1 of 5 label conditions: (1) control: QR code; (2) low-climate-impact labels; (3) traffic-light labels (TLLs); (4) high-climate-impact labels; or (5) grade-scale labels and asked to order lunch from 2 fast-food menus (1 burger-focused and 1 sandwich-focused). Main Outcomes and Measures: The primary outcome was the healthfulness of meals ordered based on a modified Nutrient Profile Index (NPI) score. Other outcomes included the estimated greenhouse gas emissions (GHGE), calorie and nutrient content, and cost of selected meals, as well as perceptions of labels and knowledge about the climate contribution of different foods. Results: Among the 6210 participants (3274 [51.0%] women; mean [SD] age, 48.1 [18.1] years), 1236 participants were randomized to the control group; 1249 to low-climate-impact labels, 1243 to high-climate-impact labels, 1235 to TLLs; and 1247 to grade-scale labels. Demographic characteristics were similar across groups. Only the TLL was effective at promoting more healthful food choices in the burger restaurant compared to the control label (mean [standard error] NPI score: 49.93 [0.18] points vs 49.25 [0.18] points; P < .001). There were no ecolabel effects on NPI score in the sandwich restaurant. Compared to control, the TLL led to 15.2% lower GHGE for meals in the burger restaurant and 29.8% lower GHGE for meals in the sandwich restaurant. The TLL was the most noticeable (78.30% [95% CI, 75.35%-81.26%]; P < .001) and had the highest percentage of participants who correctly reported what the label was about (88.72% [95% CI, 86.04%-91.39%]; P < .001). There were no differences in the overall cost of the meals selected by label condition. Conclusions and Relevance: Findings from this web-based randomized clinical trial showed that TLL-style ecolabels on restaurant menus may be an effective strategy to promote more sustainable and, in some instances, more healthful food choices without increasing consumer costs. Trial Registration: ClinicalTrials.gov Identifier: NCT06909019.