Improving adolescents’ knowledge of healthy and sustainable nutrition through school-based educational interventions: a pilot study in a rural Hungarian secondary school

Abstract Background Adolescents’ knowledge of healthy nutrition and sustainability is important for both public health and environmental sustainability. This pilot study aimed to assess knowledge of healthy nutrition and sustainability among 15–16-year-old students in a rural Hungarian secondary school and to compare the short-term effects of two educational intervention formats. Methods Three intact classes were assigned to the long intervention, short intervention, or control condition. Knowledge was assessed at baseline and two weeks after the intervention. The long intervention group received four 45-min educational sessions, the short intervention group received one 45-min session, and the control group received no intervention. Scores were calculated for healthy nutrition, sustainability, and their combination. Non-parametric statistical tests were applied, including the Kruskal–Wallis test and Dunn’s post hoc test with Bonferroni correction. Results The final analytical sample included 69 students. At baseline, the short intervention group had significantly lower healthy nutrition scores than the control group (12.00 vs. 15.00; p = 0.006), indicating that initial knowledge was not uniform. After the intervention, the long intervention group achieved significantly higher healthy nutrition scores (16.00) than both the short intervention group (13.00) and the control group (13.00). No significant between-group differences were found for sustainability scores at baseline or post-intervention. Change-score analyses showed that both intervention groups improved significantly more than the control group in healthy nutrition, sustainability, and combined knowledge scores. No significant differences in change scores were observed between the long and short intervention groups. Conclusions The findings indicate that students were not fully familiar with several aspects of healthy nutrition and sustainability, highlighting the need for education in this field. School-based education may improve adolescents’ knowledge in the short term, and even a single structured session may produce measurable improvement. However, the additional benefit of a longer, more practice-oriented format was not confirmed. Given the close relationship between healthy nutrition and sustainability, future educational programmes may benefit from addressing these topics in an integrated manner. Future studies should include larger samples, longer follow-up, and assessment of attitudes, practices, and behavioural change.