A prospective, randomized controlled study, using stable isotope methodology, is proposed to determine whether an oral nutrition support regimen, containing pressurized whey protein and glucose, is more effective at normalizing the metabolic response to surgery than a standard peripheral parenteral nutrition (PPN) support regimen, containing amino acids and glucose, in colorectal surgical patients studied before and after surgery. The effectiveness of the nutrition support regimens will be determined by: whole body protein balance, synthesis rates of hepatic secretory proteins, resting energy expenditure and substrate utilization, as well as circulating metabolites concentrations.

Inclusion Criteria:

1. The American Society of Anesthesiologists' (ASA) class 1 to 3
2. Colorectal surgery for non-metastatic disease (including right, transverse, left, sigmoid, subtotal, total, and hemicolectomy)
3. Nutrition status: 18.5 < body mass index < 30 kg/m2, stable weight over the preceding three months (< 10% body weight loss), serum albumin > 35g/l

Exclusion Criteria:

1. History of hepatic failure (Child-Pugh score A-C and transaminases outside the normal range)
2. Renal impairment (Serum Creatinine outside normal range)
3. Cardiac failure (New York Heart Association (NYHA) classes I-IV)
4. Hepatic, Renal, Cardiac transplant
5. Endocrine disorders: diabetes type I & II, hyper and hypothyroidism
6. Active inflammatory bowel or diverticular disease (Crohn's Disease, Ulcerative Colitis)
7. Musculoskeletal or neuromuscular disease
8. Anemia defined as hematocrit < 30, hemoglobin < 10 g/dl, albumin < 25 mg/dl
9. Previous spine surgery or scoliosis limiting use of epidural
10. Pregnancy
11. Use of Steroids
12. Milk protein allergy or intolerance