Safety and Tolerability of the Ketogenic Diet in Amyotrophic Lateral Sclerosis (ALS)

Inclusion Criteria: 1. Familial or sporadic ALS diagnosed as probable, laboratory-supported probable or definite according to the World Federation of Neurology El Escorial criteria 2. Age 18 or older 3. Capable of providing informed consent and complying with trial procedures 4. Gastrostomy tube in place for the prior month 5. Appel ALS score less than 100 6. Able to stand on a scale with assistance 7. For patients with Appel ALS scores greater than 80, availability of caregiver who is willing and able to: * Prepare, administer and log tube feeds * Check and log gastric residuals * Assist with weighing subject at home if necessary 8. Willing to chart food intake during the six-month study 9. Patients either not taking Riluzole (Rilutek) or Minocycline or on a stable dose of these for 30 days 10. Not taking Coenzyme Q10 or on a stable dose and brand for 30 days 11. Absence of exclusion criteria Exclusion Criteria: 1. Forced vital capacity \<50% of predicted 2. Dependence on mechanical ventilation for more than 12 hours per day 3. Exposure to any experimental agent within 30 days of onset of this protocol 4. Women who are pregnant or planning to become pregnant 5. Women of childbearing potential not practicing contraception 6. Enrollment in another research study within 30 days of or during this trial 7. Mini-Mental State Exam (MMSE) score \<20 8. Patients with symptomatic cardiac disease or hypercholesterolemia 9. Patients with myocardial infarction within 6 months of this trial 10. Renal dysfunction defined as BUN and creatinine \>2XULN 11. Known mitochondrial disease 12. BMI\<18.5 13. Prior use of a 4:1 ketogenic diet or Atkins diet within 1 month of this trial 14. Impaired liver function, defined as AST or ALT of 3 X ULN 15. Patients who have a pacemaker or other internal electronic medical device