association of dietary behaviors with physical activity in a nationally representative sample of children and adolescents: the caspian- iv study

background: nutritional health and adequate physical activity (pa), especially in childhood and grow periods, have a substantial role in health. this study assessed the association of dietary behaviors (main courses and snacks intake) with pa in children and adolescents. materials and methods: using multistage random cluster sampling method, a representative sample of 14,880 school students were selected from urban and rural areas of 30 provinces of iran. through a validated questionnaire, daily consumption of main course ( breakfast, lunch, and dinner) as well as daily consumption of different snacks and health foods ( fast foods, milk, vegetables, dry fruits, fresh fruits, sweetened beverages, salty snacks and sweets) were recorded for every participants. information of past week weekly frequency of leisure time pa was collected. results: overall, 13,486 out of 14,880 students (response rate: 90.6%) participated in this survey. participants consisted of 6,640 (49.2%) girls and 75.6% urban residents; their mean and standard deviation (sd) age was 12.47 (3.36) years. daily consumption of fresh fruits (odds ratio [or]: 1.35, 95%confidence interval [ci]: 1.20-1.52), dried fruits (or: 1.21; 95%ci: 1.06-1.40), vegetable (or: 1.39; 95% ci: 1.24-1.56), and milk (or: 1.35; 95% ci: 1.21-1.52) increased the odds of high pa compare to low pa in adjusted model.  skipping the breakfast, lunch and dinner decreased the odds of moderate and high pa compare to low pa (p<0.05).  conclusion: present study showed that dietary behaviors are associated with pa level in iranian adolescents. findings should be used for better evidence based planning of health promotional programs in these age groups.