This is the second tutorial in the nutrition series. Previously I looked at metabolism in critical illness. In this tutorial I start to answer many of the questions that arise on rounds principally: how many calories does the patient need? How much protein? What are the routes of food administration? Is there a benefit to post pyloric feeding tubes? Should I feed the stomach continuously or by bolus? Should I check gastric residual volumes? I provide you with the answers to these questions using the best available evidence.