The study presented has as main aims to detect tendencies and markers of abnormal and risky eating behavior, as well as the distribution between groups of young people from different cultures. A random sample of 770 pupils has been used, male and female, 384 of which are Spanish and 386 Mexicans. The age ranges from 15 to 18 with a mean of 16.23 and SD= 1.06. The analysis of results revealed that there are statistically significant differences between nationalities and genders; Mexicans presenting higher restrictive eating behavior rates with a mean of 1.51 against Spanish with a mean of 1.43. Comparing between genders, female of both nationalities practise dieting behaviour more frequently. According to ideal weight, the higher percentage of the total men wished to weigh the same or even more; being 71.80% for Spanish and 68.50% for Mexican. Regarding women, it is the other way round; they wished to weigh less and much less, being lower between Spanish women with a 60.30% against Mexican women with an 84.20%. The analysis confirms that being a woman (gender effect), represents the higher significant differences. Therefore, they have higher rate of risky dieting than me