Gliomas are invasive and aggressive tumors, which derive from glial or stem cells, and after neoplastic transformation, acquire glial cell characteristics. Treatment of high-grade gliomas includes measures to relieve symptoms and eliminate or control the tumor. Surgery, radiation, and chemotherapy are the most common options. Recent findings revealed that dietary interventions to reduce glucose and glycolytic pathways could have a therapeutic effect. CKD is a restrictive therapeutic diet consisting of a 4:1 ratio of fat-to-CHO and protein. Fat provides up to 90% of the caloric intake, while overall CHO intake is less than 50 g/day. CKD reducing blood glucose levels and increasing ketone body levels stimulates biochemical changes to achieve systemic ketosis. Though, evidence for CKD in clinical practice is still limited. This study focuses on the classic ketogenic diet (CKD), adjusted for each patient's energy needs by dieticians to achieve ketosis. The primary outcome is to assess the efficacy of CKD to extend the survival of patients with high-grade gliomas and brain metastases. Historical controls will be used to compare the outcome measurements.
