The purpose of this study was to evaluate the body mass index (BMI), physical activity (PA) and dietary habits of students living in a province of North Greece, who exercised or not exercised regularly and compare the findings to the international guidelines for health. A total of 575 male and female students participated in the study and were divided into sub-groups according to their age (9-13 yrs, n=240 & 14-17 yrs, n=335) and their athletic experience (athletes, n=243 & non-athletes, n=332). The data were collected by the Physical Activity & Lifestyle Questionnaire (PALQ) and the 24 hour Dietary Recall Questionnaire (24hDRQ). Data analysis showed that 85% of male and female athletes met international guidelines of PA for health, accumulating >60′ minutes/day of moderate-vigorous PA (MVPA), as compared to 37% of non-athletes. Moreover, the athletes accumulated significantly more MVPA as compared to their peers who did not participate in organized sports. Eating habits did not differ between athletes and non-athletes, and a percentage of 83% did not meet the international recommendations for a healthy diet. However, no statistically significant differences were found in BMI between athletes and non-athletes. These finding revealed that a significant proportion of the participants did not meet the recommended dietary and PA guidelines of international health organizations, and it seems that regular exercise did not protect young people from the problem of overweight. Thus, it is necessary to implement prevention programs that aim to improve food choices and increase PA.