The current study aimed to determine if subjective bulimic episodes (SBEs) and objective bulimic episodes (OBEs) have different reactive effects to self-monitoring. Fourteen women with bulimia nervosa (57%) or binge eating disorder (43%) were diagnosed using the Eating Disorder Examination (EDE; version 12.0). During the 7-days post-interview, participants filled out daily self-monitoring records indicating the food consumed and any episodes of loss of control over eating. These records were reviewed and coded for OBEs and SBEs using the EDE coding scheme. Paired samples t-tests indicated that participants' average number of daily OBEs significantly decreased from baseline to the period of self-monitoring (t = 2.41, p < 0.05, Cohen's d = 0.90), whereas there was a significant increase from baseline to self-monitoring in their average number of SBEs (t = −2.41, p < 0.05, Cohen's d = 0.86). Of the 12 participants who showed a decrease in OBEs, 75% showed a concurrent increase in SBEs. The data suggest that the reactivity of OBEs to minimal or brief interventions may in part be due to binge drift, or the reduction of OBEs at the expense of increasing SBEs. Copyright © 2006 John Wiley & Sons, Ltd and Eating Disorders Association.