The Web-based intervention is based on the principles of cognitive-behavioral therapy and motivational interviewing. In part 1, patients analyze their eating attitudes and behaviors. Part 2 focuses on behavioral change. During the program, patients receive messages, assignments, exercises, and psychoeducation from their therapists. The program includes four assignments and at least seven contacts in part 1 and six assignments and at least 14 contacts in part 2. Examples of part 1 assignments are daily registering of eating behavior and related thoughts and feelings, analyzing eating situations, and describing advantages and disadvantages of the disorder. Part 2 assignments include setting goals in regard to eating, exercising, checking weight, and (if applicable) compensation behaviors, changing thoughts, changing behaviors, improving self-image, and writing a relapse prevention plan. The average duration of the program is 15 weeks. After completing the program, patients can participate in an aftercare program consisting of six weekly sessions.