Nutritional supplementation in postoperative recovery is still debated. Functional impairment is known to develop both secondary to inflammatory processes or secondary to reduced nutritional intake (e.g. disease induced anorexia). Since major surgery represents a traumatic event, surgical patients are at increased risk of malnutrition due to starvation, activation of neuroendocrine stress axis, inflammation and the subsequent increase in metabolic rate. Gastrointestinal surgery in particular can create additional problems as it often directly affects and limits dietary intake postoperatively and these effects frequently continue after discharge. Whereas manifest malnutrition occurs in about 15% of general surgical patients and in about 40% of oncology patients, postoperative weight loss of 5 to 9% occur in all surgical patients during the first two months. Moreover studies have shown that the nutritional status generally declines in hospital and both functional and nutritional status deteriorate for two months after discharge in malnourished surgical patients.