Background: Good health requires healthy eating. However, individuals with eating disorders, such as anorexia nervosa, require treatment to modify their dietary behaviours and prevent health complications. There is no consensus on the best treatment practices and treatment outcomes are usually poor. While normalising eating behaviour is a cornerstone in treatment, few studies have focused on eating and food-related obstacles to treatment. Objective: The aim of the study was to investigate clinicians’ perceived food-related obstacles to treatment of eating disorders (EDs). Design: Qualitative focus group discussions were conducted with clinicians involved in eating disorder treatment to get an understanding of their perceptions and beliefs regarding food and eating among eating disorder patients. Thematic analysis was used to find common patterns in the collected material. Results: From the thematic analysis the following five themes were identified: (1) ideas about healthy and unhealthy food, (2) calculating with calories, (3) taste, texture, and temperature as an excuse, (4) the problems with hidden ingredients and (5) the challenges of extra food. Discussion: All identified themes showed not only connections to each other but also some overlap. All themes were associated with a requirement of control, where food may be perceived as a threat, with the effects of food consumption resulting in a perceived net loss, rather than a gain. This mindset can greatly influence decision making. Conclusions: The results of this study are based on experience and practical knowledge that could improve future ED treatments by enhancing our understanding the challenges certain foods pose for patients. The results may also help to improve dietary plans by including and explaining challenges for patients at different stages of treatment. Future studies could further investigate the causes and best treatment practices for people suffering from EDs and other eating disturbances.