Nutritional support in surgical patients has evolved from simple provision of adequate calories to retard loss of lean body mass to the provision of specific nutrients in an attempt to manipulate metabolic and immune responses. Although still limited, the current understanding of this complex subject indicates that the type, route, amount, and composition of nutritional support provided to patients can affect their outcome. Further studies are, however, needed to better characterize the exact nutritional support that is most beneficial for a specific disease state and a specific patient.