The effective management of individuals with severe mental illnesses (SMIs) requires an holistic approach that offers reliable symptom control, but also addresses other clinical, emotional and social needs. The physical health of individuals with an SMI is often poor, with many being overweight or obese, having hypertension, diabetes or dyslipidaemia, and at significant risk of developing cardiovascular disease or other comorbidities. We have recently reviewed current UK and US guidelines for the management of individuals with schizophrenia and bipolar disorder, and found very different approaches to the holistic care of people with SMIs, especially in relation to the management of physical health and cardiovascular risk. UK guidelines acknowledge the high risk of physical morbidity and mortality in individuals with an SMI, but fail to address in detail the specifics of physical health monitoring and lifestyle management. US guidelines are more descriptive in terms of the type and extent of monitoring recommended, but there are inconsistencies between the guidelines produced by different organizations, and studies in the field suggest that none of them is being adequately implemented. Clear and consistent recommendations on how and when to monitor weight, cardiovascular function, and metabolic parameters and, importantly, what to do with the results, would support clinicians wishing to integrate physical and mental healthcare. Publication of specific recommendations on evidence-based physical health interventions that can work for people with SMIs would also help primary care and mental health services improve general well-being in their patients with severe mental illnesses.