Nonalcoholic fatty liver disease is defined as an excess accumulation of fat in the liver in patients with little or no history of alcohol consumption. It is considered difficult to identify and treat in this early, reversible stage and is strongly associated with obesity, insulin resistance (including type 2 diabetes mellitus), metabolic syndrome, and dyslipidemia. The prevalence in both adults and children is increasing. Treatment guidelines from around the world agree that weight loss is the first line of treatment. We discuss diet-related therapies including weight loss and with a special focus on the Mediterranean diet. We present a case from our family medicine practice to demonstrate how evidence-based medical nutrition therapy, along with prescription medication to assist in weight management, can be used to help adult patients with nonalcoholic fatty liver disease. We also comment on recommended treatment for pediatric patients.