The food served in psychiatric institutions may in general be described as a standard diet similar to that served in somatic hospitals, with no or little adjustment made to the special needs of the individual psychiatric patient. The emphasis on physical activity is also generally low. This paper presents results and strategies in a sample of sixteen Norwegian psychiatric institutions that have undertaken a one-year weight management programme with focus on structural changes in dietary and physical activity practices. Prevention and treatment of weight gain in psychiatric patients is difficult, but not impossible. All institutions included in this project have made changes in the dietary practice and the routines for physical activity, with less severe weight problems in the patients as a result. Coordinated approaches are necessary if the efforts are to succeed.