Patients with severe traumatic brain injury often require long-term stay in the ICU with significant stress metabolism and consecutive hypermetabolism and catabolism. Optimized energy and protein supply with early enteral support when feasible prevents malnutrition and improves clinical outcome. Adjustment of nutritional support using gastrointestinal and metabolic monitoring prevents overfeeding in the acute phase of critical illness. While vitamins and trace elements should be substituted on a daily base, high-dose supplementation of micronutrients cannot be generally recommended.