The provision of adequate nutrition support for patients with traumatic brain injury (TBI) has been a clinical challenge for decades. The primary and secondary injuries create unique metabolic derangements along with accompanying issues such as optimal timing and route of nutrition, appropriate fluid and electrolytes, drug administration, rehabilitation, and dysphagia. Enteral nutrition is clearly established as the preferential route of nutrition support for this population vs parenteral nutrition. There appears to be a consensus on early initiation of enteral nutrition, but less definitive are recommendations on advancement timing and formula components. Nutrition therapies should include exact fluid resuscitation goals specific for TBI and strict electrolyte monitoring to avoid extreme fluid, electrolyte, or glucose shifts that could be detrimental to the patient. While the critical care patient often tolerates small bowel feeding, the long-term rehabilitation patient should transition to and tolerate gastric feeding. Drug-nutrient and adverse drug reactions such as diarrhea should be routinely evaluated in patients receiving enteral nutrition. Monitoring for dysphagia is critical to avoid the costly negative aspects associated with aspiration and to capitalize on quality of life and appropriate oral nutrition. Emphasizing the priority of early nutrition support within a multi-disciplinary team may be the critical key for successful provision and tolerance of nutrition support in the TBI population.

The provision of nutrition has traditionally been driven by the desire to provide adequate calories. However, over the past decade it has become evident that provision of excess calories can be detrimental to patients' outcomes in both critical care and long-term care settings. This review examines patient populations for whom hypocaloric nutrition can be both appropriate and beneficial. In specific situations, critically ill patients, such as those with obesity, stroke, and spinal cord injury, may have decreased energy requirements. In patients with spinal cord injury, the level of injury significantly correlates with the extent of reduced caloric energy expenditure. Ventilator-dependent patients with amyotrophic lateral sclerosis (ALS) have decreased energy needs; energy expenditure for ALS patients is lower than the predictive equation value. Aging patients will have decreased energy needs relative to a reduction in lean body mass. Patients with cerebral palsy (CP) have significantly lower caloric requirements than anticipated using predictive equations. Patients with CP pose a particular challenge in nutrition assessment. Several studies demonstrate that patients with CP have significantly lower caloric requirements than anticipated using predictive equations; thus, patients with CP benefit from indirect calorimetry. Provision of nutrition for obese patients is briefly addressed, as this is an increasingly important consideration for nutrition support in both the critical care and long-term care settings. When indirect calorimetry is not available, clinicians should remember that most patients will have low resting energy expenditure regardless of functional status and require frequent evaluation during institution of nutrition recommendations to guard against overfeeding and obesity.