Ketogenic Diet & Functional Recovery in Moderate to Severe Traumatic Brain Injury

Inclusion Criteria: * complicated mild (GCS 13-15), moderate (GCS 9 - 12) to severe (GCS ≤ 8) traumatic brain injury (TBI) between 2-30 days post injury * Admitted to Loma Linda University surgical intensive care unit (SICU) Exclusion Criteria: * history of comorbid ischemic stroke following qualifying TBI * history of premorbid brain injury with associated loss of consciousness * history of psychiatric disorder * history of premorbid neurological disorder or neurosurgical intervention * pregnancy * depressed GCS score due to acute intoxication * liver dysfunction as defined by liver enzymes 5 times the upper limit of normal or chronic cirrhosis * acute renal failure according to the Risk, Injury, Failure, Loss of kidney function, and End-stage kidenty disease (RIFLE) classification * abdominal surgery during the same admission * type 1 diabetes * gastroparesis * dyslipidemia * severe asphasia * known history of metabolic disorders that are a contradiction for ketogenic diet (KD) such as primary carnitine deficient, carnitine palmitoyltransferase (CPT) I or II deficiency, carnitine translocase deficiency, beta-oxidation defects, pyruvate carboxylase deficiency, or porphyria * prealbumin (transthyretin) levels of \<10 mg/dL within 3 days of admission * Metal, implanted device (ICP monitor), pregnancy, claustrophobia, or other contraindication to MRI