Alterations in metabolism occur after acute SCI, but the marked hypermetabolic response seen after acute traumatic brain injury appears to be blunted in SCI patients by the flaccidity of denervated musculature after spinal cord transection/injury. As a result, REE is lower than predicted after acute SCI. Equation estimates of REE in these patients have proven to be inaccurate. Comparative Class II medical evidence supports the use of indirect calorimetry as the recommended technique to assess energy expenditure in both the acute and chronic settings among patients with SCI. Protein catabolism does occur after acute, severe SCI, and marked losses in lean body mass due to muscle atrophy result in huge nitrogen losses, prolonged negative nitrogen balance, and rapid weight loss. Nutritional support of the SCI patient to meet caloric and nitrogen needs, not to achieve nitrogen balance, is safe and may reduce the deleterious effects of the catabolic, nitrogen wasting process that occurs after acute spinal cord injury. It appears that early enteral nutrition (initiated within 72 hours) is safe, but has not been shown to affect neurological outcome, the length of stay, or the incidence of complications in patients with acute SCI. © 2013 by the Congress of Neurological Surgeons.