Overfeeding of the critically ill patient, in particular, in the post-traumatic phase is associated with worsened outcome. Overfeeding increases hyperglycemia and hyperlipidemia, hypercapnia, eventually resulting in liver dysfunction, electrolyte disturbances, and immune dysfunction. Reaching energy and protein target of nutritional therapy in critically ill patients should only be achieved after about a week after admission to the intensive care unit. For many critically ill patients, the target of 70% of the protein and energy target in the first week in the intensive care unit after slow adjustment is sufficient as hepatic gluconeogenesis usually contributes to a major amount of energy needed. Examples of individual adjustment of calories and protein according to the phases of stress metabolism and the individual metabolic tolerance are discussed.