High Five! - School-based Prevention of Overweight and Obesity Among 6 to 9 Year Olds

The goal of this interventional study is to assess the effectiveness of the school-based "High Five!" program in reducing overweight, obesity and high blood pressure in children aged 7-9 years old. The main questions it aims to answer are: * Does participation in the "High Five!" program reduce the proportion of child participants with elevated body mass index (BMI), waist and hip circumference, and blood pressure? * Does participation in the "High Five!" program increase adherence to recommended health behaviors (healthy eating, physical activity, screen time management, and sleep hygiene) among participating children? Researchers compare "High Five!" to the school practice as usual to see if this program works to prevent overweight and related health problems in children. Students participate in 6 sessions. Sessions 1-5 are dedicated to five health-related topics such as mental health, nutrition, physical activity, screen time and sleep while session 6 serves as a summarizing and reinforcing lesson. Sessions are based on active methods (play, individual / small group work) and carried out in accordance with detailed scenarios by trained specialists: the class teacher and the school nurse. Parents/guardians of participating students are engaged in promoting healthy behaviors and creating a supportive home environment via self-reading of the "portions of knowledge" on the topics covered by the program and completion of home tasks with their children.