Inclusion Criteria:

1. Histologically proven glioblastoma multiforme (GBM).

2. Unequivocal evidence of tumor recurrence or progression by MRI (or CT brain if a
patient can not undergo MRI). Radiotherapy (with or without radiosensitizing drugs)
must have been completed in the past. The earliest a patient can be enrolled in this
study after radiotherapy is 14 days. The scan done prior to study entry documenting
progression will be reviewed by the primary investigator to document tumor volume
changes to provide a gross assessment of growth rate.

3. Patients may have had: a) no prior chemotherapy, b) 1 prior adjuvant chemotherapy, c)
1 prior adjuvant chemotherapy followed by 1 regimen for recurrent disease, or d) 1 or
2 prior chemotherapy regimens for recurrent or progressive tumor.

4. All patients must sign an informed consent indicating that they are aware of the
investigational nature of this study in keeping with the policies of this hospital.

5. Enrollment MRI or CT scan of the brain must be performed within 14 days of
registration. Patients having undergone recent resection of recurrent or progressive
tumor will be eligible for assessment of response as long as there is residual
enhancing evaluable disease that is documented by appropriate neuroimaging and
patients have recovered from the effects of surgery. Patients who after surgery have
no residual enhancing disease will still be eligible for enrollment, but only
assessable for time to progression, and not for response.

6. Patients must have a life expectancy > 8 weeks.

7. Patients must have a Karnofsky performance status of > or = 60 (Karnofsky Performance
Scale).

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.

9. Patients must have adequate bone marrow function (ANC> or = 1,500/mm3 and platelet
count of > or = 100,000/mm3), adequate liver function (SGPT and alkaline phosphatase
= or <2 times normal, bilirubin = or <1.5 mg%), and adequate renal function (BUN or
creatinine = or <1.5 times institutional normal) prior to starting therapy.

10. All acute toxic effects (excluding neurotoxicity or alopecia) of any prior therapy
must have resolved to Common Toxicity Criteria (CTC) grade = or < 1.

11. Patients who are eligible for the trial and who require resection of their tumor may
begin the dietary restriction component of the therapy prior to their surgery
providing the time to surgery is greater than 6 days. In these patients, tissue
collected at surgery will be analysed for the effects of treatment. After surgery,
patients will resume an ad lib diet for anywhere from 5-14 days prior to the
re-initiation of the dietary methionine restriction at the same dose level and
continuance with the trial.

Exclusion Criteria:

1. Patients with a history of any other cancer (except non-melanoma skin cancer or
carcinoma in-situ of the cervix), unless in complete remission and off of all therapy
for that disease for a minimum of 3 years.

2. Patients have one or more of the following conditions may not participate in this
study: a) active infection; b) pregnancy and/or disagree to practice adequate
contraception; c) disease that will obscure toxicity or dangerously alter drug
metabolism; d) serious intercurrent medical illness.