Background & Aim: Overweight and obesity is one of the major health problems among children and adolescents. 13-19 year olds are at higher risk of obesity in adulthood and physiological and internal problems. This study was done to determine the effect of habits and nutritional education on the knowledge of obese high school students and their parents in Khorramabad.
Material and Methods: In this quasi - experimental study, 152 obese students and their parents were selected from 12 high schools of Khorram Abad in 2006 which had been identified in the previous study, and they were randomly assigned to either the intervention or the control groups. The educational program consisted of nutritional education and modifying dietary habits were implemented by a skilled nurse through face-to-face method and an educational booklet. Students and parents' nutritional knowledge were evaluated with twelve 4-item   questions (with 1.5 points given to each correct answer) before and after implementing the educational program. Knowledge scores of <7, 7-12, and 13-18 were considered poor, fair and good, respectively. The collected data were analyzed by T-test and Chi-square test.     
Results: Difference in adolescents' dietary habits and nutritional knowledge between the two groups at the baseline was not statistically significant, but the difference in scores was statistically significant between the intervention and control group after the intervention (p = 0.003), so that good knowledge level was found to be more frequent in the case group (47.4%). Parents' dietary habits and nutritional knowledge was not statistically significant different between two groups at the baseline, but this difference was statistically significant after intervention (p = 0.046), so that good knowledge level was found to be more frequent in the case group (46.1%).
Conclusion: The dietary habits and nutritional education is effective in enhancement of obese students and their parents Knowledge, and could change the condition of obese students and affect the view and behavior of them and their parents in the program of controlling the obesity.