<qa>  How many participants are needed to participate in the study?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. 