Using calorie-counting and fitness-tracking technologies is concerning in relation to eating disorders. While studies in this area typically assess one aspect of use (e.g., frequency), engagement with a device or application is more complex. Consequently, important relationships between the use of these technologies and the eating disorder symptomatology might remain undetected. The current study therefore used comments from online eating disorder-related forums to generate comprehensive qualitative insights into engagement with a popular calorie-counting and fitness-tracking application, MyFitnessPal.