Résumé : [en] Many studies have analysed psychopathological dimensions of relationship that adolescent have with food and body. But few researches have focused attention on links between psychosocial dimensions such as social representations (Moscovici, S. 1961; Lalhou, S.1995) and adolescent typical practices of eating (with family and peers) and body (diet and sport).This research is aimed to describe and to analyse representations and practices of eating and body of 60 adolescents (30 females, 30 males) equally distributed on high and low social class aged from 14 to 16 years. Hypothesis supposes changes of eating and body representations and practices according to sexe and social class of subjects.A multimethodogical approach was adopted. Data were collected in Avril 1999 in two roman colleges. Qualitative and quantitative instruments were administered in this order: a) associative network (words association), b) semi-structured interviews (18 questions about eating and body ideas and practices), c) body drawing, d) eating family drawing, e) questionnaires (Eating Attitudes Test, Eating Disorders Inventory 2). A preliminary interviews content analysis with ALCESTE (Reinert, M.1993) draw out 8 discourse classes. Four classes are linked to eating representations and practices: a) Eating Family Practice (16,85 %); b) Eating with Friends (8, 61%); c) Eating quantity and preferences (15, 97%); d) Daily meals organisation (7,40%).Others four classes are linked to body representations and practices: e) Eating Problems (20, 13%); f) Body Health and beauty (8,07%); g) Diets and Sports ( 10,86%); h) Food quality (12, 10%). Results show a general picture of eating and body representations and practices. Eating with family is a very important social situation: a script characterised by social actors, rules, actions and contexts is outlined. Food intake control and food preferences seem pregnant dimensions in identity construction process face to family and peers.Naive theories about eating disorders are constructed. Finally diet, sport and food quality seem central in shaping and modelling body.