 With an effect size of d.32 between the DBI and the active control condition regarding the main outcome variable eating disorder pathology, with three conditions in total, and at least 3 measurements pre, post and 6-months follow-up the investigators need at least 260 participants with p .05, an expected drop-out of 15, and reliability of measures set between .75 and .95 to attain a power of at least .95. Given the recruitment channels, the investigators expect a much larger number than 260 to participate in the study, and to ensure adequate power for analyses using random effects and to take further drop-out over time into consideration the investigators aim for at least 400 participants. 