The literature recognizes differences in the prevalence, eating disorders (ED) symptoms and eating habits/behaviours by sex, but few studies in Portugal considered this subject.

To explore associations between sex, Body Mass Index (BMI), Eating Attitudes Test-25 (EAT-25) dimensions and items, the EAT-25 score dichotomized by the cutoff of 19 (a score equal/above 19 indicates “possible” ED) and, finally, some items about eating habits/behaviors; to verify possible associations between sociodemographic variables and items assessing eating habits/behaviours.

308 adolescents (M = 14,5 years; DP = 1,67; girls, n = 184, 59,7%) answered a sociodemographic questionnaire and the EAT-25.

There were no significant associations between sex, categorized and dimensional BMI, EAT-25 dimensions, categorized EAT-25 (cutoff of 19) and items assessing eating habits/behaviors. However, some items of the EAT-25 revealed a significant association with sex. Most adolescents from both sexes presented a score below the cutoff of 19. The frequency with which young people drink sodas and eat vegetables is associated with father's educational level. The frequency with which adolescents eat vegetables and fast food is associated with the school area they attend.

Eating habits/behaviours are not as much negative as documented in some literature. There does not seem to exist significant sex differences regarding eating attitudes, “possible” ED, BMI and eating habits/behaviours. However, there are sex differences regarding some of the specific symptoms of EAT-25. It is good to verify that both sexes reveal a low prevalence of “possible” eating behaviour disorder, although girls reveal a higher value.