Behavioural determinants of healthy and environmentally friendly diets in French university students

Although encouraging the shift toward sustainable diets in young adults is a major challenge to preserve population and planet health, the precursors of sustainable diets in this population remain unknown. This study aimed to identify the behavioural determinants of healthier and more environmentally friendly diets among university students. A sample of 582 French university students reported their food consumption using an online 125-item food frequency questionnaire. The nutritional quality (adherence to French recommendations, sPNNS-GS2) and the greenhouse gas emissions (GHGE) of students' diets were calculated for an isocaloric diet. Behavioural determinants were measured based on a literature review and classified into the Capability, Opportunity, Motivation Behaviour (COM-B) framework. Linear models, adjusted for socioeconomic characteristics, were run to identify the most prominent behavioural predictors of nutritional quality and GHGE of students' diets. Higher cooking skills (β = 0.38, p = 0.01) and health motives (β = 0.91, p < 0.001) were associated with higher nutritional quality. Greater environmental knowledge was linked to lower GHGE (β = -0.07, p = 0.002), while health and weight control motives were associated with higher GHGE (β = 0.26, p = 0.02 and β = 0.39, p < 0.001). Enhancing cooking skills and environmental knowledge could enable healthy and environmentally friendly diets, but health-based motives can act as a lever and as a barrier.