Of the roughly 55% of the United States population that is considered overweight, half meet the criteria for obesity. Obesity is associated with serious health risks, but many clinicians graduate from medical school without a clear understanding of the effects of the foods that they and their patients consume. Obesity is more prevalent in people with mental illnesses, which poses an even greater challenge to clinicians. Antipsychotic treatment can cause weight gain, and mentally ill patients generally lack an understanding of nutrition as well as the ability to afford healthier foods. Therefore, clinicians must educate themselves about appropriate measures for preventing weight gain before or immediately after initiating antipsychotic therapy. Strategies for weight gain management that have proven effective in clinical trials include regular check-ups, lifestyle and medication counseling, medication assessments, behavioral control programs, and pharmacologic intervention. These approaches are necessary for clinicians to consider if efforts at reintegration of mentally ill patients are to succeed.