The FLY-project: study protocol for mixed methods research to explore the complex social dynamics of sustainable food-related lifestyles in youth in practical education.

Background: The present-day food system is a key driver of climate change and biodiversity loss, making it imperative for populations to shift towards more sustainable diets. The involvement of youth in this transition is vital because they are in a formative period where their identities, values, and norms, including their food behaviours, are being shaped. Special attention should be paid to youth in practical education because they are often overlooked in existing studies, yet evidence suggests they may lack the necessary resources to support dietary changes, resulting in lower levels of pro-environmental food-related behaviours. The aim of the FLY (Food-related Lifestyles in Youth) project is to study how sustainable food-related lifestyles and underlying factors develop in early adolescence, particularly in Dutch youth in practical education, how these spread in social networks, and to develop community-level intervention strategies to support youths' transition to sustainable food-related behaviours.

Methods/design: The FLY-project adopts a mixed-method approach. First, two literature reviews are conducted. A systematic review assesses how capabilities, opportunities and motivation are associated with sustainable food behaviours in youth, and how these elements interrelate in determining sustainable food-related lifestyles. A scoping review studies community-level interventions that target sustainable and healthy food-related behaviours. Second, focus groups are conducted to explore the barriers and facilitating factors concerning capabilities, opportunities, and motivations that Dutch youth in practical-level education experience to transition to more sustainable food-related lifestyles. Third, a cohort survey study is conducted to track the dynamic interplay between capabilities, opportunities, motivation, and changes in specific sustainable food behaviours over time, and to assess the diffusion of sustainable food-related lifestyles via social (media) networks. Fourth, an experimental research programme tests promising intervention approaches, some of which are co-created with youth, targeting relevant underlying factors.

Discussion: This paper describes the rationale, conceptual framework, design and methods of the FLY-project. The FLY-project contributes to an understanding of underlying factors of sustainable food-related behaviours in adolescence and results in a multi-component intervention toolkit, with a particular focus on youth in practical education programmes.