Obesity is associated with early mortality and has overtaken smoking as the health problem with the greatest impact on quality of life, mortality, and morbidity. Despite public health initiatives and numerous commercial enterprises focusing on weight loss, obesity rates continue to rise. In part, this is because obesity is a multifaceted, complex illness, impacted by numerous social, psychological, and behavioural factors that are unrecognized in most current initiatives. One significant factor associated with obesity is mental illness. While having a psychiatric illness does not make weight gain inevitable, it does often require that additional tools be added to lifestyle recommendations around diet and exercise. The following article reviews the common approaches to obesity management and addresses how these strategies can be implemented in psychiatric care. It is important that health professionals involved in the care of people with a mental illness become familiar with the interventions available to control and treat the obesity epidemic, as this will improve treatment compliance and ultimately lead to improved physical and psychological outcomes.