Background:
Few lifestyle factors have been simultaneously studied and reported for Saudi adolescents. Therefore, the purpose of the present study was to report on the prevalence of physical activity, sedentary behaviors and dietary habits among Saudi adolescents and to examine the interrelationships among these factors, using representative samples drawn from three major cities in Saudi Arabia. Methods: This school-based cross-sectional study was conducted during the years 2009/2010 in three cities; Al-Khobar, Jeddah and Riyadh. Participants were 2908 secondary-school males (1410) and females (1507) aged 14-19 years, randomly selected using a multistage stratified sampling technique. Measurements included weight, height, sedentary behaviors (TV viewing, video games and computer use), physical activity using validated questionnaire, and dietary habits. Results: Very high proportion (84% for males and 91.2% for females) of Saudi adolescents spent more than 2 hours of screen time daily and almost half of the males and three quarter of females were not meeting the daily physical activity guidelines. The majority of adolescents did not consume daily intakes of breakfast, fruits, vegetables and milk. Females were significantly (p < 0.05) more sedentary, much less physically active, especially vigorously and consume fewer days per week of breakfast, fruits, milk and diary products, sugar-sweetened drinks, fast foods and energy drinks compared with males. However, females’ intakes of French fries/potato chips, cakes/donuts and sweets and chocolates were significantly (p < 0.05) higher than the males. Screen time significantly (p < 0.05) correlated inversely with the intakes of breakfast, vegetables and fruits. Physical activity had significant (p < 0.05) positive relationships with fruits and vegetables intakes but not with sedentary behaviors. Conclusion: The high prevalence of sedentary behaviors, physical inactivity and unhealthy dietary habits among Saudi adolescents is of major public health concern. There is an urgent need for national policy promoting active living and healthy eating and reducing sedentary behaviors among children and adolescents in Saudi Arabia.