Patients with severe anorexia nervosa have a high mortality and relapse rate, yet specialist services and practitioners are few. A significant minority need detention with involuntary treatment. Furthermore, the mean age at presentation is 16 years, where detention under the Mental Health Act 1983 or parental consent is unclear and variable. This article addresses the implications of the proposed new Mental Health Act for people with eating disorders. The main issues are those of incapacity, assessment procedures, community detention, detention in 16–18-year-olds, implications for carers and resource implications. We hope to show that eating disorders, just like other illness categories, have special needs that cannot be blanketed under one process and that the Act has positive features, but also presents significant concerns.