AbstractBackground Young adulthood is an optimal time for intervening in dietary behaviors. Young adults in the United States strongly value environmental sustainability, so appealing to these values could be a promising strategy to improve dietary quality. Objective We examined whether a "stealth" intervention that explicitly appealed to sustainability (climate-impact labels, climate-focused social comparison messages) while also promoting healthier options (through healthy and sustainable swap recommendations) improved the healthfulness of food selections. Methods Participants (US young adults ages 18-25) were randomized in Qualtrics to the experimental (n=1, 074) or control (n=1, 075) arm and selected one protein, frozen meal, and snack they would most like to purchase. All foods varied by healthfulness (Nutri-Score algorithm, range A-E). Participants in the experimental arm received nudges appealing to sustainability, including viewing front-of-package labels showing whether the food had low-, medium-, or high-climate-impact and, if they selected a high-climate-impact food, viewing a climate-focused social comparison message and swap recommendation to low- or medium-climate-impact foods with a healthy Nutri-Score (A or B). Control arm participants did not receive any nudges. Results Experimental arm participants selected foods that were 3. 9 points healthier than participants in the control arm (pd=0. 67). Effects of the nudges on healthfulness did not differ by gender, education, financial situation, red meat consumption, political beliefs, or interest in sustainability (ps for interaction≥0. 13). Experimental arm participants selected foods with a carbon footprint 0. 76 kg CO2-eq/100g lower than control arm participants (pd=0. 93). Compared to the control, experimental arm participants thought more about sustainability (ppp=0. 02), and similar amounts about healthfulness (p=0. 32) when selecting foods. Conclusions "Stealth" nudges appealing to sustainability while also incorporating health considerations could encourage a wide range of young adults to select more healthful and sustainable foods. Trial registration ClinicalTrials. gov (NCT06119165) and AsPredicted. org (https: //aspredicted. org/QXHMR3).
Prestemon et al. (Mon,) studied this question.