Process Evaluation of a School-Based Program Aimed at Preventing Obesity in Adolescents from Lima and Callao, Peru

The study aims to describe process evaluation measures of the three-year Health Promoting Schools' obesity prevention program in Lima and Callao, Peru, and to assess factors that influenced the implementation of the intervention leading to the mentioned process outcomes results. The program was implemented in four public high schools located in low-income areas of Lima and Callao. Embedded in a Health Promoting School Intervention, the program consisted of two main components-an education program and several environmental activities. Quantitative data were collected and analyzed based on dose delivered and reach for each specific activity. Dose received was analyzed by satisfaction scores related to six specific activities. Furthermore, qualitative data including documentation of activities and transcriptions from individual in-depth interviews were qualitatively analyzed to identify factors influencing the implementation. The education component of the Health Promoting Schools' program achieved a 78.4% average nutrition sessions delivery in 2015 and 88.0% in 2017; while for PA sessions, the average delivery in 2015 was of 79.7% and 93.8% in 2017. In the case of reach, at least 75% of total students participated in all sessions per year. Nevertheless, there were differences in terms of delivery and participation in a number of environmental activities within and between schools during the program period. Differences in delivery included education sessions for parents, teachers, Junior Health Promoters, and school food kiosk staff, besides execution of physical activity events every year. Impeding factors included the complexity of the overall intervention, limited strategies to facilitate program implementation and those to maintain the participation of subjects, and related contextual factors.