LAUSR

Abstract Objective: To identify the prevalence of unhealthy dietary behaviours and their social-ecological influences in adolescents. Design: The study used a sequential explanatory mixed-methods design, which begins with the collection of quantitative data, followed by the collection of qualitative data to explain and enrich the quantitative findings. Quantitative data were collected via a global school-based student health survey and were analysed using quantitative approaches. Qualitative data were obtained via focus group discussions and were analysed thematically. Setting: Middle and high secondary schools in Taza city, Morocco. Participants: Our quantitative analyses included 764 students (14–19 years). For the qualitative part, seventeen focus group discussions were conducted with 100 participants (fifty-six adolescents, twenty-six parents and eighteen teachers). Results: Of total student participants, 46·1 % skipped breakfast, 60·6 % had inadequate intake of fruits and vegetables (F&V), 39·4 % consumed soft drinks and 28·0 % consumed fast foods. All of these dietary behaviours could coexist in the same person except for inadequate intake of F&V. Gender, academic performance, age, perceived family income and education level of mother were associated with unhealthy dietary behaviours. Qualitative findings identified seven themes regarding social-ecological influences on adolescents’ dietary behaviours: cognitive, affective/biological, lifestyle, outcome expectation, social network, accessibility/availability and macro-level influences. Conclusions: The prevalence of unhealthy dietary behaviours in our study group is a concern. Dietary behaviours are the result of inseparable interactions among social-ecological influences. Modifiable factors identified may be useful when designing a future intervention aimed at improving breakfast and F&V consumption and reducing fast/snack-food consumption among adolescents.