Patients suffering from alcohol use disorder (AUD) are at risk for malnutrition. The mechanisms are presented in this article. Nutrition disorders in the patient with AUD can include malnutrition, micronutrient deficiencies, overweight and obesity. They may contribute to tissue damage and to oncological and cognitive disorders encountered among patients with AUD. Refeeding syndrome can appear during the withdrawal period. A nutrition evaluation should be included in the evaluation of all patients with AUD.