Metabolic and gastrointestinal alterations associated with trauma can rapidly lead to malnutrition and its accom-panying complications. Malnutrition is harmful to the pa-tient because it is associated with impaired wound heal-ing, muscle weakness, immune dysfunction, and infec-tious complication, and is an independent risk factor for morbidity and mortality. Thus, adequate nutrition support is essential in management of trauma patients. The pur-pose of this paper is to expound on the metabolic alter-ations and to provide a rationale for nutrition support in trauma patients. (J Korean Soc Parenter Enter Nutr 2013;5(3):90-95)