Managing Glioblastoma Multiforme with Fasting and a Ketogenic Diet

This is a prospective observational study. Patients diagnosed with stage 4 glioblastoma will be informed of the potential benefits and risks of using fasting and a ketogenic diet in glioblastoma. If the patient opts to incorporate this approach into their lifestyle, they will be supported with information and guidance prior to commencing the regimen via a clinical visit at Waikato hospital, followed by weekly emails and, if requested by the patient, video (Zoom) sessions as needed. The recommended regimen will consist of 5-7 days of fasting, alternated with 3 weeks of a ketogenic diet, for a period of up to 2 years post-diagnosis (or more if the patient remains alive, well, and wishes to continue). Observational data (such as MRI scans) will be collected as per the patient's routine care by their treating oncologist, who will be informed of the fasting and ketogenic diet regimen. There will be no further study visits at the hospital other than routine oncology care, unless the situation warrants (such as an unexpected admission for a medical complication of any description). (1) Materials. - Fasting materials will include a CareSens blood glucose and ketone monitor (patients will buy). - Ketogenic diet materials include a diet plan with recipes (on average, per 1,750 kcal per day, the recipes will be composed of 152 g of fat (67 g saturated), 75 g of protein, 16 g net carbohydrate, and 11 g of fiber). This plan is designed by the lead investigator. Patients will also be able to source their own ketogenic diet recipes, although these will be checked by the lead investigator to ensure the fat/carbohydrate/protein ratio conforms to the ratio above. (2) Procedures. - Fasting procedure will be a fluid-only fast (water, salt supplementation, black coffee, tea, or bone broth) for 5-7 days in a row. Lemon and lime juice, apple cider vinegar, 1 tsp chia or flax seeds, or a slice of fruit (not to be eaten) may be added to each glass of water. Up to 1 tsp of unsweetened almond milk, cream, coconut oil, butter, MCT oil, or a pinch of cinnamon or nutmeg may be added to coffee, which will be limited to 2-4 cups per day. There will be regular weekly email contact and occasional video sessions (one on the initial fast, more as required later, anticipated to be 20-60 minutes long) to maintain contact with patients and help them surmount any difficulties. - Ketogenic diet will be as per the diet plan, no limit on the amount of food that may be eaten (ad libitum). - It is anticipated there will be approximately one fast per month, with all remaining time spent on the ketogenic diet. (3) Delivery. - The patient (and partner, if present) will deliver the fasting and ketogenic diet interventions to themselves. The study investigators will only provide guidance and aid in troubleshooting via video throughout. The conversations will be part educational, part question and answer sessions, part support (as any routine clinic visit would be, albeit via video) so as to maximize the chances of success with the diet and fasts. It is anticipated that the sessions will be anywhere from 20-60 minutes in duration. Patients will also be contacted regularly via email to provide encouragement and review any potential problems, email frequency will vary depending on patient need (anticipated to be 1-2 emails a week during the ketogenic diet phase and 3-4 emails a week during the fasts). (4) Location. - Fasting and ketogenic diet therapy will largely take place in the patient's own home. (5) Adherence. - This will be assessed by monitoring of blood glucose and ketone (beta-hydroxybutyrate) levels, daily during the fasts and three times per week for the ketogenic diet (aiming for a mean glucose to ketone ratio of < 6).