People with a mental illness show a growing incidence of obesity, and higher rates of metabolic syndrome when compared with the general population. This paper reviews research on obesity, cardiovascular disease and type 2 diabetes, with the aim of directing clinical attention towards the improvement of patient physical health. A systematic search of cross-discipline databases and journals provided peer-reviewed research for analysis, and national statistics allowed for the investigation of differences in rates of occurrence between people experiencing a mental illness and the general population. Treatment effects via psychotropic medications and lifestyle factors such as poor diet and low levels of exercise suggest that ongoing monitoring is necessary to prevent major physical disorders in people experiencing a mental illness. To aid clinicians, a comprehensive set of clinical guidelines have been developed for the physical assessment and ongoing monitoring of mental health patients.