Dieting, a behavioral phenomenon which is becoming more frequent among adolescents, is certainly involved in the pathogenesis of eating disorders, especially anorexia nervosa (AN), and may result in an unbalanced nutrition. Our study aimed at identifying girls with symptoms of AN and describing their diets. We assessed girls with symptoms by using the Eating Attitudes Test and considered girls with a score > or = 20 as having symptoms of AN. To evaluate their diets, a "modified" 24-hour recall was applied on three alternate days. Twenty-one percent of the 279 girls studied showed symptoms of AN. Analysis of the food intake showed that calories, calcium and iron were below the recommendations of the Standing Committee on the Specific Evaluation of Dietary Reference Intakes (DRI Committee) and the National Research Council, while protein and carbohydrate were within the recommended range and fat was above the percentage of recommended total energy intake. Compared to girls without symptoms, they had a significantly smaller intake of calories and iron, and a higher intake of protein. Findings shown in this paper point out the need for intervention in adolescents because their dieting behavior can predispose to an eating disorder.