A Phase 2 Study of the Ketogenic Diet vs Standard Anti-cancer Diet Guidance for Patients With Glioblastoma in Combination With Standard-of-care Treatment

Inclusion Criteria: * Adults 18 years or older * Newly diagnosed glioblastoma (Within 2 months of initial diagnosis by histopathology) * Not started standard of care chemotherapy and/or radiation therapy for glioblastoma * Karnofsky Performance Status (KPS) ≥ 70 * Ability to read, write and understand either English OR Spanish * Written informed consent obtained from subject and ability for subject to comply with the requirements of the study. Exclusion Criteria: * Patients with recurrent glioblastoma * Genetic disorders that affect lipid metabolism. Including but not limited to pyruvate carboxylase deficiency, porphyria, primary carnitine deficiency, carnitine palmitoyltransferase I or II deficiency, carnitine translocase deficiency, beta-oxidation defects * Inability to wean steroids below 8mg dexamethasone / day or equivalent * Body Mass Index (BMI) \< 21kg/m2, unless the site Principal Investigator deems safe * Currently pregnant or nursing * Patients receiving other experimental therapy Note: Off-label therapy use is permitted * Comorbidities that in the opinion of the investigator limit the patient's ability to complete the study * Food preferences incompatible with keto diet * Using a pacemaker, implantable cardiac defibrillator, neurostimulator, cochlear implants (removable hearing aids permitted), or other electronic medical equipment, unless the site Principal Investigator deems safe * Inability to participant in standard of care MRIs