Preoperative Nutrition for Crohn's Disease Patients

Mulnourished patients will drink an enteral polymeric formula suited to their energy expenditure calculated by 25-30 kcal/kg and at least 1 gr/kg of protein, a minimum of 1500 ml (1500 kcal, 54 gr of protein). The amount of formula to achieve nutritional requirements are based on body weight, but the average intake is of 6-8 cups of formula (36-48 scoops of formula mixed with 1260-1680 ml of water to achieve a concentration of 1 kcal per ml). During this period patients will be guided to avoid eating and drinking anything but the enteral formula. The formula will be supplied to the patients by the investigators. The formula used for this study will be VITAL - suitable for people with disease-related malnutrition and malabsorption. Vital 1.5kcal is peptide-based, nutritionally complete formulation for the dietary management of active phase of Crohn's disease. VITAL includes all the nutritional macro and micronutrients and can serve as a sole source of nutrition.

Mulnourished patients will receive a high energy / protein diet.

Well nurished patients will receive a standard nutrition