Cognitive behaviour therapy for eating disorders (CBT-ED) outperforms other treatments for non-underweight eating disorders in adults, but we have limited ability to match CBT-ED to individual profiles. We examined if we could identify who benefits most from two forms of 10-session CBT-ED; one emphasizing early behaviour change with substantial content on improving body image (CBT-T), and the other including motivational work and no content on body image using chapters from self-help books (CBTm). Participants were 98 consecutive referrals to the Flinders University Services for Eating Disorders. Fourteen clinical psychology postgraduates delivered the treatment under expert supervision. Outcome measures were completed on five occasions: baseline, 4-, 10-, 14- and 22-weeks post-randomisation. Our primary outcome was global eating psychopathology. Moderators included motivation (readiness and confidence to change) and body avoidance and body checking. Intent-to-treat analyses showed no difference between the groups with a significant main effect of time associated with large effect size improvements, commensurate with longer forms of CBT-ED. Participants with lower readiness to change in CBTm had significantly greater decreases in disordered eating over follow-up compared to those with low motivation in CBT-T. People with lower readiness to change might benefit from the incorporation of motivational work in CBT-ED.