The aims of this study were to investigate the number of sessions and time required for a clinical meaningful symptomatic change with a guided self‐help treatment and to assess the predictive value of early response and other potential predictors of end‐of‐treatment clinical status. Participants were 42 patients with a diagnosis of bulimia nervosa or ED not otherwise specified. Survival analyses (Kaplan–Meier) were performed to estimate the median time required to attain a 51% reduction in bulimic symptoms. Logistic regression was used to assess predictors of symptom remission. Results showed that the median time to achieve a 51% reduction in binge and purge frequencies was 3.68 and 3.77, respectively. This change occurred at session 3 for 50% of the participants. Early response was the most significant predictor of binge eating remission. No pretreatment predictors of time to achieve early response were found. These results have implications for allocating treatment resources in a stepped‐care intervention model. Copyright © 2013 John Wiley & Sons, Ltd and Eating Disorders Association.