Introduction: The Póngale Vida ® model for the prevention of childhood obesity recognizes schoolteachers as key actors in this work, but this requires strengthening their knowledge and practices to promote healthy eating and physical activity for school children. Objective: To evaluate an educational intervention to increase teacher's self-efficacy for fruit and vegetable consumption and physical activity, within three public schools in Costa Rica. Methods: Jara and Rivera's educational proposal for intervention (2011) was implemented and evaluated with 70 teachers. There were evaluations before and after the intervention, it had demographic characteristics, lifestyle variables, self-efficacy measurements for physical activity and fruit and vegetables consumption; also, biochemical and anthropometric measures. Focus groups were used to identify facilitators and barriers at personal, family and work levels. Results: After the intervention, almost 25% of teachers increased their physical activity practices, as well as self efficacy for physical activity practice and fruits and vegetables consumption. The main barriers were a double work burden linked with feminine gender roles, limiting beliefs, and, lack of urgency in preventing diseases. Conclusions: The educational intervention contributed in increasing self-efficacy regarding eating fruit and vegetables and the practice of physical activity of participating teachers. 

Keywords: Barriers and facilitators, educational intervention, physical activity, school environment, socio-ecological model