(P23-021-25) The Impact of Sustainability-Focused Nudges on the Healthfulness of Food Selections: A Randomized Trial of Young Adults

Objectives: To examine the impact of sustainability-focused nudges (climate-impact labels, social comparison messages, and swap recommendations) on the healthfulness of food selections.

Methods: Participants were US young adults ages 18-25 who completed an online survey in Qualtrics. Participants were randomized to the experimental (n=1,074) or control (n=1,075) arm and were instructed to select one food they would most like to purchase in three different food categories: proteins, frozen meals, and snacks (17 foods per category). Foods in the experimental arm included front-of-package labels that communicated the climate impact of the food (low/medium/high) based on the food’s carbon footprint (operationalized as the food’s greenhouse gas emissions (kg CO₂-eq/100g)). If a participant selected a food with a high-climate-impact label, they were shown a social comparison message and offered swaps to low- or medium-climate-impact foods. Participants in the control arm did not see any labels, messages, or swaps. The primary outcome was the healthfulness of food selections, operationalized using an inverted continuous Nutri-Score score. The inverted Nutri-Score scale ranged from -12 to 30 for the products shown in the study, with higher scores indicating a higher nutritional value (i.e., healthier product). A secondary outcome was the carbon footprint of food selections. Primary and secondary outcomes were analyzed using linear regression.

Results: Participants in the experimental arm selected foods that were, on average, 3.9 points healthier than participants in the control arm (p < 0.001, d=0.67). Participants in the experimental arm selected foods with a carbon footprint that was 0.76 kg CO₂-eq/100g lower than participants in the control arm (p < 0.001, d=0.93).

Conclusions: Sustainability-focused nudges could encourage young adults to select healthier and more sustainable foods.

Funding Sources: Wellcome Trust; Eunice Kennedy Shriver National Institute of Child Health and Human Development; National Heart, Lung, and Blood Institute