As initial nutritional support, patients randomised to the 'EN only' group will receive glucose 5% at 40 ml/hr. EN will be initiated on the evening of the second ICU day. From the morning of the third ICU hospitalisation day on, the amount of glucose 5% to be given will be the same as the volume of PN the patient theoretically would require to receive 100% of presumed caloric needs based on the amount of EN delivered the previous 24 hours. When the patient is able to eat, the parenteral regimen (glucose 5%) will be reduced to 50% and eventually stopped. Whenever oral (+ enteral) intake is below 50% of calculated caloric needs, the PN (glucose 5%) will be (re)-started. If these patients would need to stay for more than seven days on the ICU and enteral feeding of at least 80% of the calculated calories is not possible, they will be switched to EN and PN on day eight.