New approaches to develop sensory-hedonic based interventions to promote healthier and more sustainable eating in school canteens.

The promotion of sustainable diets that prioritise plant-based (PB) foods is essential for both human and environmental health. Childhood and adolescence shape lifelong taste preferences and dietary habits, making them ideal periods for promoting healthy and sustainable eating. Schools, where students consume up to half of their daily energy intake, offer a unique opportunity to instill these eating habits. Although sensory strategies have demonstrated significant potential in increasing the acceptance of healthy and sustainable foods, their application in school settings remains largely underexplored. This is particularly true for interventions targeting adolescents—especially those from lower socioeconomic backgrounds—and for efforts promoting legumes, a key component of PB diets. This gap underscores the need for innovative approaches that cater to the specific needs and preferences of this demographic, offering promising avenues for enhancing PB food consumption. One promising approach is the use of co-creation methodologies, which involve collaboration with stakeholders to develop new PB dishes. However, co-creation is not yet identified by a univocal approach. Another promising strategy is the use of hedonic contrast (HC), which involves simultaneously presenting foods with different levels of appeal. Though HC has been shown to influence food liking and consumption, its effect on food-related emotions and its combination with repeated exposure remain unexplored. This PhD research aimed to address these critical gaps by employing sensory-hedonic strategies—including food co-creation and an intervention exploring the HC effects—to promote the acceptance and consumption of PB dishes in school canteens. Initially, this study adopted a multi-methods approach, involving co-creation with adolescents and chefs to develop innovative, healthy, and sustainable legume-based dishes for school canteens. The co-creation process, which involved iterative sessions of focus group discussions, Jobs-to-be-Done, free association tasks, and SCAMPER technique, enabled us to identify innovative dish concepts that catered to adolescents' preferences and needs. The results demonstrate that co-creation and understanding individual differences in liking and emotional responses can lead to the development of well-received legume-based dishes for school canteens. Additionally, this study proposes a methodological framework for co- creation with adolescents and professional chefs that can be adapted to a variety of food service environments. Building on this foundation, a simple methodological approach was developed to create a menu capable of exploring HC effects. To achieve this, various pairs of starter dishes (tasty vs. bland versions) were developed and evaluated, with the goal of identifying a suitable pair to precede the innovative co-created PB main dish. This approach ensured that the selected starter dish pair would create a significant HC, enhancing the ability to effectively explore the HC effect in an intervention study. The intervention study explored the effect of HC on liking, emotions, and consumption of an innovative co-created PB main dish, when it is served as part of a course meal at school, in a repeated exposure experiment. The findings confirmed a HC effect generated by a bland starter on the consumption of the innovative PB main dish and they also revealed that a bland starter determines the increased intensity of positive high-arousal emotions related to food. No HC effect on liking was observed. These effects of HC were not stable over time and they disappeared after five exposures. These findings highlight the significant impact of even minor shifts in liking and emotions on consumption, with important implications for meal planning in settings like school cafeterias, where strategic menu design can influence food choices and consumption behaviours. In conclusion, this PhD study provides a comprehensive understanding of the complex factors shaping PB food choices among adolescents in school canteens and proposes effective strategies to promote healthy and sustainable eating habits among this age group by increasing the acceptance of these foods. The study's findings have far-reaching implications for healthcare professionals, food caterers, and policymakers in schools and beyond, with the potential to inform the development of effective interventions, policies, and practices that can contribute to a healthier, more sustainable, and environmentally conscious food environment.