Time since menarche, weight gain and body image awareness among adolescent girls: Onset of eating disorders?

Background. Eating, body weight and shape feelings and behaviours of female adolescents in relation to the time since their first menstrual period were studied. Method. Three hundred sixty three female school students, aged 12-17 years participated in a cross-sectional computer survey. Results. There was a significant increase in body weight following menarche including a rapid rise from 7-12 months after menarche (47.4kg, 95% CI 45.2-49.7, 56.9kg 95% CI 54.0-59.8). Students did not immediately adjust their perception of body weight to incorporate this rapid rise. The discrepancy between actual and desired weight was greatest 7-12 and 13-24 months after menarche. Weight losing behaviours and associated feelings around body image increased significantly following menarche in adolescents of all body weights. Increases were related to body weight and time since menarche, but not to age. Binge eating commenced more than 6 months after menarche and purging behaviour after 12 months. Conclusion. Both time since menarche and increase in body weight following menarche are associated with increasing concerns about eating, body image and weight losing behaviour. Some young women develop eating disorders. Menarche and subsequent weight gain appear as a risk factor for the onset of eating disorders.