8. Patients must have recovered from the toxic effects of prior therapy and/or at least 2 weeks from vincristine, 6 weeks from nitrosoureas, and 3 weeks from procarbazine administration. Patients must have recovered from the toxic effects of any other cytotoxic drugs which they may have received and must be 1 week from the completion of any non-cytotoxic drug therapy (e.g. 13-cis-retinoic acid, thalidomide, tamoxifen, etc.). For those patients previously treated with temozolomide, they may enroll and start the diet even 1 day after their last temozolomide dose.