There are enough clinical evidence showing that early enteral/oral nutrition reduced both the risk of infection and length of hospital stay.

Look at Enhanced Recovery After Surgery (ERAS) Group Recommendations published in Archives of Surgery 2009;144(10):961-969.

This is just part of a package of measures to minimise the disturbance to physiology through either open or laparoscopic surgery and calorific nutrition may be given either as food or nutritional supplements that are absorbed in the upper small bowel.