Introduction Healthy living is a lifestyle based on the individual adopting behaviour aimed at maintaining, ensuring and developing well-being, while also helping to make the right decisions regarding their own health. Individuals need to take responsibility regarding healthy eating habits, getting adequate physical activity, effective communication and stress management in order to live a healthy life. 1,2 Rapid growth, and physiological, emotional and social development and changes are the most important characteristics of adolescence. These factors can have an effect on eating habits and well-being. Behaviours like bad eating habits, inadequate physical activity, poor coping can not only affect mental activities like learning, understanding and comprehension, they can also trigger obesity and other medical problems. 2 The problem affects many low- and middle-income countries on a global scale, particularly in urban environments. Between 1980 and 2014, global prevalence of obesity more than doubled. 3 A review of international literature on studies conducted in different countries reveals the following: according to Gunter et al.'s 4 study carried out in the United States on students aged 5-12 years, 17.8% of girls and 20.8% of boys were found to be obese, whereas in Shih et al's 5 study carried out in Taiwan on students aged 11-12 years, the percentage was 15.2% among both boys and girls, and in Ha et al's 6 study carried out in Korea on students aged 12- 14 years, 8.5% of girls and 16.8% of boys were identified to be obese. According to the National Health and Nutrition Examination Survey (NHANES) survey carried out in the United States, 16.9% of children and adolescents in the 2- 19 age group in 2009-2010 were reported to be obese. 7 Recent studies carried out in various parts of Turkey suggest that obesity is a growing medical problem that has come to affect school-age children. According to Karayagiz-Muslu et al's 8 study, 17.8% of children aged 7- 15 years in Aydin were obese and 13.3% of children aged 7-15 years were overweight. Savashan et al's 9 study carried out in Ankara reported that 7.5% of children in the 6-11 age group were obese and 11.1% of children in the 6-11 age group were overweight. Obesity prevalence in Turkey was found to be 8.5% (boys 10.1%; girls 6.8%) in the 0-5 age group and 8.2% (boys 9.1%; girls 7.3%) in the 6-18 age group. 10 Factors contributing to obesity risk include poor health behaviours, irregular and incorrect eating habits and a sedentary lifestyle. This is why it was thought that this group should be given priority in scope of school health nursing practices and adolescents with obesity risk were included in the study. It is possible to control obesity in adolescents linked with malnutrition or irregular eating patterns and sedentary lifestyles with positive and effective interventions to J Pak Med Assoc 1698 RESEARCH ARTICLE The impact of health behaviours development training on healthy lifestyle behaviours amongst adolescents with obesity risk: A school example in a city in western Turkey Duygu Yesilfidan, Filiz Adana Abstract Objective: To determine the impact of health behaviours development training on healthy lifestyle. Methods: This pre-experiment research was conducted at a junior high school governed by Aydin Provincial Directorate of National Education in Aydin, Turkey, from November 2014 to December 2015, and comprised students. All the students with obesity risk were included. Participants were asked to complete the questionnaire, and Healthy Lifestyle Behaviours Scale II.SPSS 18 was used for data analysis. Results: Of the 1,042 students, 78(7.48%) were included in the study. Of them, 38(48.7%) were girls and 40(51.3%) were boys. The overall mean age was 11.77±0.92 years. It was found that healthy lifestyle behaviour improved after the training (p<0.05). Conclusion: Adolescents assessed with the Healthy Lifestyle Behaviour Scale II had higher post-training scores. Keywords: Obesity, Adolescent, Health, Teaching. (JPMA 67: 1698; 2017) Adnan Menderes University, Faculty of Nursing, Public Health Nursing, Aydin, Turkey. Correspondence: Filiz Adana. Email: filizadana@yahoo.com