Most patients with severe complex obesity presenting for bariatric-metabolic surgery have nonalcoholic fatty liver disease (NAFLD). NAFLD is associated with central obesity, insulin resistance, type 2 diabetes, hypertension, and obesity-related dyslipidemia. Weight loss should be a primary therapy for NAFLD. However, evidence supporting intentional weight loss as a therapy for NAFLD is limited. Bariatric-metabolic surgery provides the most reliable method of achieving substantial sustained weight loss and the most commonly used procedures are associated with reduced steatosis and lobular inflammatory changes, but there are mixed reports regarding fibrosis. Surgery should complement treatment of obesity-related comorbidity, but not replace established therapy.