Design and implementation of a theory of planned behavior-based nutrition education intervention for adolescent girls in rural Nepal: a school-based cluster-randomized controlled trial.

Adolescence is a pivotal period of physical, psychological, and cognitive development during which individuals are highly vulnerable to nutritional deficiency. Undernutrition, overweight/obesity, and anemia are prominent public health concerns in low- and middle-income countries, including Nepal. Anemia affects nearly one-quarter of individuals aged 10-24 years globally, with a disproportionately high burden in resource-constrained settings. This study primarily aims to evaluate the effectiveness of a theory-driven school-based nutrition education intervention in improving dietary behaviors, health literacy, and nutritional status among adolescent girls in rural Nepal. This two-arm randomized controlled trial (RCT) evaluated the effectiveness of the Nutrition Education Intervention for Promoting Health (NEIPH) program for improving the nutritional status of adolescent girls in rural Nepal. Adolescent girls (200) with low serum ferritin levels (40.7-75.7 ng/mL), enrolled in grades 7-9 across 19 public schools in Annapurna Rural Municipality, were randomly assigned to either an intervention (103 girls from nine schools) or a control (97 girls from 10 schools) group. The intervention group received two 60-min interactive education sessions over 1 month, school-based monitoring, and a standardized educational booklet. The sessions incorporated multimedia presentations, role-play activities, group discussions, and teach-back exercises to reinforce key concepts. The control group received booklets approved by the National Health Education, Information, and Communication Center. The educational content covered balanced nutrition, dietary sources, anemia prevention, adolescent health, and menstrual hygiene and was delivered using multimedia tools and participatory techniques. The NEIPH intervention is expected to be a viable approach for improving the nutritional status and reducing anemia by influencing the behaviors of adolescent girls. The combined use of the theory of planned behavior and the teach-back method represents a novel and structured approach to enhance comprehension, promote self-efficacy, and foster sustained behavioral change. The trial is currently ongoing, and no outcome data have been analyzed. This paper provides a detailed account of the theoretical framework, intervention development, and implementation procedures to promote methodological transparency and reproducibility.