Multi-strategy instructional intervention for healthy eating intention among school going adolescents: A quasi-experimental study

Background Adolescence is a unique stage of life characterized by significant physical, psychological, and cognitive development. Maintaining healthy eating behaviors during this period is crucial for preventing various forms of malnutrition and non-communicable diseases (NCDs) such as diabetes, heart disease, stroke, and cancer. This study aimed to assess the effect of educational interventions based on the Theory of Planned Behavior (TPB) on improving healthy eating intention of adolescents in selected schools in Bardiya District. Methods A quasi-experimental study was conducted among eighth and ninth grade aged between 12–18 years from two selected public schools in Badhaiyatal Rural Municipality of Nepal, intone as an intervention (IG) and another as a control group (CG), randomly. Data were collected through self-administered questionnaires at baseline and 3 weeks after the intervention. The intervention package consisted interactive lecture, group discussion, poster, educational video, and a song, whereas the students in the control group did not receive any intervention. The educational intervention for the IG consisted of 6 sessions, each of 60 min. Data were entered and analyzed in SPSS V22, using chi-square test, paired t-test, and linear regression. Results The educational intervention led to significant improvements in knowledge and TPB constructs with these changes being statistically significant (p < 0.001). The adjusted mean score increase in TPB constructs due to the interaction of time and intervention increased from 0.47 to 5.49. The highest gain (β = 5.49; p = 0.001) was seen in the perceived behavioural control score, while a minor improvement was seen in behaviour (β = 0.47; p = 0.112). After the intervention, the net increase in healthy eating intention score was 14.8% compared to the control group. Conclusions The study concluded that educational interventions effectively improved adolescents' healthy eating intentions. Moreover, these interventions successfully encouraged positive changes in their healthy eating attitudes. Model-based and construct-oriented programs can be used in schools to promote healthy eating intentions.