Despite a dramatic increase in research on eating-related pathologies, gaps remain in our understanding of the factors responsible for the development and maintenance of dysfunctional attitudes and behaviour related to weight and eating among adolescents. A study was therefore conducted to compare eating and weight concerns among underweight, normal-weight and obese affluent adolescent girls in New Delhi. The sample comprised fifty underweight, fifty normal-weight and thirty obese girls, 16–18 years of age. Information was collected about their body image perception, weight concerns and eating attitudes by a well-structured questionnaire. Dietary intake was determined by 24 h recall and a food-frequency questionnaire. Body size was adjudged by measurements of weight, height, waist, hip and mid upper arm circumferences, and the BMI and waist : hip ratio were determined. Of the subjects, 99·2 % had a gynoid pattern of fat distribution. Concerns about excess weight were prevalent among the adolescent girls, even among those who were normal-weight and underweight. The level of satisfaction with body size decreased with increase in weight. Dieting behaviour was reported in a higher number of obese (76·6 %) compared with normal-weight (38 %) and underweight (14 %) girls. Of the obese girls, 43·3 % were found to be at a significantly (P=0·00109) greater risk of developing anorexia in the future. Characteristic dietary features of adolescence, such as missing meals, snacking and eating out, were observed. While the diets of most of the subjects were adequate in Ca, thiamin, riboflavin and vitamin C, they were found to be deficient in energy, protein, Fe, niacin, vitamin A and fibre. Thus, it is important to recognize that weight concerns and dissatisfaction with body size may pose a threat to a healthy nutritional state, and may develop into precursors of a later eating disturbance.