Background: Food systems highly contribute to anthropogenic greenhouse gas emissions and shifting towards more environmentally friendly diets is urgently needed. Enabling consumers to compare the environmental impact of food products at point-of-purchase with front-of-pack labelling could be a promising strategy to trigger more environmentally friendly food choices. This strategy remained to be tested. Methods: The effect of a new traffic-light front-of-pack environmental label on food choices was tested in a 2-arm randomised controlled trial in a virtual reality supermarket. Participants (n = 132) chose food products to compose two main meals for an everyday meal scenario and for an environmentally friendly meal scenario with or without the label. The environmental label (ranging from A: green/lowest impact, to E: red/highest impact) was based on the Environmental Footprint (EF) single score calculation across food categories. The effect of the label on the environmental impact of food choices in each scenario was tested using linear mixed models. Results: In the everyday meal scenario, the environmental impact of meals was lower in the label condition than in the no label condition (-0.17 ± 0.07 mPt/kg, p = 0.012). This reduction was observed at no nutritional, financial nor hedonic cost. The effectiveness of the label can be attributed to a change in the food categories chosen: less meat-based and more vegetarian meals were chosen with the label. In the environmentally friendly meal scenario, we demonstrated that the label provided new information to the participants as they were able to further reduce the environmental impact of their food choices with the label (-0.19 ± 0.07 mPt/kg, p = 0.005). Conclusions: Implementing a front-of-pack environmental label on food products in real supermarkets could increase awareness of the environmental impact of food and contribute to drive more environmentally friendly food choices. Trial registration: The study protocol was pre-registered prior to data collection at Clinicaltrials.gov (NCT04909372).

Background: Food consumed outside of the home is often high in energy and population level interventions that reduce energy intake of people from both lower and higher socioeconomic position (SEP) are needed. There is a lack of evidence on the effectiveness and SEP equity of structural-based (e.g. increasing availability of lower energy options) and information provision (e.g. menu energy labelling) interventions on food choice.Methods: Across two online experiments, participants of lower and higher SEP made meal choices in a novel virtual fast-food restaurant. To be eligible to take part, participants were required to be UK residents, aged 18 or above, fluent in English, have access to a computer with an internet connection and have no dietary restrictions. Participants were randomized to one of four conditions in a 2 × 2 between-subjects design: menu energy labelling present vs. absent and increased availability of lower energy options (75% of menu options lower energy) vs. baseline availability (25% of menu options lower energy). Participants also completed measures of executive function and food choice motives.Results: The analysis of pooled data from both studies (n = 1743) showed that increasing the availability of lower energy options resulted in participants ordering meals with significantly less energy on average (− 71 kcal,p < 0.001, partial η² = 0.024) and this effect was observed irrespective of participant SEP. Menu labelling had no significant effect on energy ordered (− 18 kcal,p = 0.116, partial η² = 0.001) in participants from both higher and lower SEP. Furthermore, we found no evidence that executive function or food choice motives moderated the effect of increasing lower energy menu options or energy labelling on total energy ordered.Conclusions: In a virtual fast-food environment, energy labelling was ineffective in reducing total energy ordered for both higher and lower SEP participants. Increasing the availability of lower energy options had an equitable effect, reducing total energy ordered in participants from higher and lower SEP.Trial registration: Study protocols and analysis plans were pre-registered on the Open Science Framework (https://osf.io/ajcr6/).

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.

Background: Changing the food environment is an important public health lever for encouraging sustainable food choices. Targeting the availability of vegetarian main meals served in cafeterias substantially affects food choice, but acceptability has never been assessed. We examined the effects of an availability intervention at a French university cafeteria on students’ main meal choices, meal offer satisfaction and liking. Methods: A four-week controlled trial was conducted in a university cafeteria in Dijon, France. During the two-week control period, vegetarian main meals constituted 24% of the offer. In the subsequent two-week intervention period, this proportion increased to 48%, while all the other menu items remained unchanged. Students were not informed of the change. Student choices were tracked using production data, and daily paper ballots were used to assess student satisfaction with the meal offer and liking of the main meal they chose (score range [1;5]). Nutritional quality, environmental impact, and cost of production of meal choices were calculated for each lunchtime. Food waste was measured over 4 lunchtimes during control and intervention periods. An online questionnaire collected student feedback at the end of the study. Results: Doubling availability of vegetarian main meals significantly increased the likelihood of choosing vegetarian options (OR = 2.57, 95% CI = [2.41; 2.74]). Responses of the paper ballots (n = 18,342) indicated slight improvements in meal offer satisfaction from 4.05 ± 0.92 to 4.07 ± 0.93 (p = 0.028) and in liking from 4.09 ± 0.90 to 4.13 ± 0.92 (p < 0.001) during control and intervention periods, respectively. The end-of-study questionnaire (n = 510) revealed that only 6% of students noticed a change the availability of vegetarian main meals. The intervention led to a decrease in the environmental impact of the main meals chosen, a slight decrease in nutritional quality, a slight increase in meal costs and no change in food waste. Conclusions: Doubling availability of vegetarian main meals in a university cafeteria resulted in a twofold increase in their selection, with students reporting being more satisfied and liking the main meals more during the intervention period. These results suggest that serving an equal proportion of vegetarian and nonvegetarian main meals could be considered in French university cafeterias to tackle environmental issues. Trial registration: Study protocol and analysis plan were pre-registered on the Open Science Framework (https://osf.io/pf3x7/).