We hypothesize that the combination of these components will safely improve the provision of energy and protein compared to usual care. We postulate that this increased provision of calories and protein may translate into improved clinical outcomes, particularly for the patients at the extremes of weight, but the current study is not powered to demonstrate such a difference. The purpose of this pilot study is to assess the feasibility, acceptability, and safety of this new feeding protocol, "The Enhanced Protein-Energy Provision via the Enteral Route in Critically Ill Patients: The PEP uP protocol."