Patients treated in the ICU already have a premorbid condition. Nutritional therapy needs to focus on energy and protein amount, micro and macronutrients, antioxidants and the route of nutrition. ICU acquired weakness persists for years and needs to be addressed. More protein intake is associated with lower in-hospital mortality. Timing of protein dosage is of great importance. A gradual increase from low protein during the first 2 days of ICU stay to intermediate on day 3-5 and high protein intake from day 6 is associated with lower 6-month mortality. A very high protein enteral formula (8g/100 ml) is suitable as first-line nutritional treatment for critically ill patients as it offers a solution for adequate protein provision according to nutritional guidelines without overfeeding risk.