Effects of 3 Day Preoperative Immunonutrition in Well-nourished Patients With Gastrointestinal (GI) Cancer Undergoing Surgery

Inclusion Criteria: * Patients with GI cancer (stomach, pancreas, small and large bowel and rectum) histologically proven * Well nourished patients as defined by a total score of \<3 on the nutritional screening tool NRS-2002 (46) (Appendix III) * Patients who are \>= 18 years of age; * Patients who have signed a written Informed Consent (Appendix I) prior to admission to the study; * Patients who have an ECOG performance status of 0, 1 or 2 (Appendix II). * Patients able to orally consume 750 mL or more of liquid a day prior to surgery Exclusion Criteria: * Patients who have co-morbid conditions, uncontrolled metabolic conditions or psychiatric conditions that might make tolerance or evaluation of the feeding formula difficult; * Patients who are pregnant; * Patients with cardiac failure as defined by the Goldman classification class\>3 * Patients with respiratory failure (FEV\<0.8l/sec) * Patients with renal failure (Cr \>= 3mg/dl or dialysis patients) * Patients with hepatic dysfunction (Child \>A) * Patients suffering from an intestinal obstruction or ileum * Patients with an Hb level of \<=8 g/dL experiencing gastrointestinal hemorrhaging * Patients with HIV, HCV, HBV * Patients requiring immunosuppression treatments * Patients undergoing emergency surgery * Other patients determined by a study investigator to be inappropriate for enrolment in this study