Multicenter study of the effect of Elemental diet for Perioperative nutrition in Laparoscopic colorectal Surgery.

Interventions: Elemental diet group: 900mL intake of Elental is performed on the day before surgery. 300mL intake is performed by two and a half hour before the operation as far as possible. 300mL of Elental is taken when the seated position is possible after five hours of operation. 900 mL/day intake of Elental is performed one or two days after surgery as far as possible. Three days after surgery, dietary intake (rice porridge in half degree) is started and Elental is taken in 300-900 mL/day. Four days after surgery, rice porridge in full degree is started and medication of Elental is discontinued.
Control group: Fasting is performed on the day before surgery and the operation day. Intake of fluid is only allowed for two days after surgery. Rice porridge in half degree is started three days after a surgery. Rice porridge in full degree is started four days after a surgery.
Primary outcome(s): The ratio of patients which fulfilled all the items of the criteria for discharge less than postoperative 7 day.
Study Design: Parallel Randomized