# One definitive ketogenic diet trial in glioblastoma, then stop

Source: https://onco.cc/ideas/idea-nl-ketogenic-gbm-definitive-trial/  
OnCo record `idea-nl-ketogenic-gbm-definitive-trial` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Patients with brain tumours are sold ketogenic diets on the strength of mouse data and small feasibility studies. A single adequately powered trial with dietitian support would either prove it or let clinicians say clearly that it does not work.

## Summary

Fifteen years of feasibility studies have shown ketogenic diets are tolerable for a few months in glioblastoma and have not shown efficacy. Because the diet is marketed directly to patients and is a common reason for conflict with treating teams, the cost of not knowing is high. No company will fund a diet trial; a philanthropic or cooperative-group trial with adherence biomarkers (blood ketones), a pre-registered stopping rule and a commitment to publish either way is the appropriate instrument.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: A supervised ketogenic diet maintained for six months alongside standard chemoradiation and temozolomide does not improve overall survival in newly diagnosed glioblastoma compared with a standard healthy diet (null hypothesis to be tested with power to detect a 3-month median difference).
- Rationale: The Warburg rationale is plausible but tumours adapt to use ketones and lactate; steroids undermine ketosis; ERGO2 was null but brief. A definitive answer protects patients from an intervention with real costs (weight loss, quality of life, expense) if it fails, and mobilises adoption if it works.
- Proposed test: Randomised phase 2/3 (about 300 patients) in newly diagnosed IDH-wildtype glioblastoma, stratified by MGMT status and steroid use, with dietitian-delivered ketogenic diet vs Mediterranean-style diet, ketone-verified adherence, OS primary endpoint, quality of life and body composition secondary, and pre-registered publication regardless of result.
- Maturity: early-clinical
- Actor: philanthropy

## Sources

- Bottleneck evidence (Misinformation and unproven therapies): Johnson et al., Cancer misinformation and harmful information on Facebook and other social media (JNCI 2022): https://doi.org/10.1093/jnci/djab141

## Connected records

- cancers: [Glioma & glioblastoma](https://onco.cc/cancers/glioblastoma/)
- fronts: [Diet, Exercise & Lifestyle](https://onco.cc/fronts/nutrition-lifestyle/)
- technologies: [Ketogenic diets in glioblastoma](https://onco.cc/technologies/ketogenic-diet-glioblastoma/), [Metabolic therapy: starving the tumour of a nutrient](https://onco.cc/technologies/metabolic-therapy/), [Oncology nutrition assessment and medical nutrition therapy](https://onco.cc/technologies/nutrition-screening-mnt/)
- drugs: [Temozolomide](https://onco.cc/drugs/temozolomide/)
- terms: [Unproven diet claims (alkaline, juice, 'anti-cancer' diets)](https://onco.cc/terms/unproven-diet-claims/), [Warburg effect](https://onco.cc/terms/warburg-effect/), [Warburg-effect diet claims ('sugar feeds cancer')](https://onco.cc/terms/warburg-effect-diet-claims/)
- trials: [ERGO2: ketogenic diet and fasting during re-irradiation of recurrent glioma](https://onco.cc/trials/ergo2/)
- bottlenecks: [Failures are hidden](https://onco.cc/bottlenecks/b-negative-results/), [Funding follows fashion, not burden](https://onco.cc/bottlenecks/b-funding-allocation/), [Misinformation and unproven therapies](https://onco.cc/bottlenecks/b-misinformation/)
- key papers: [Cancer Misinformation and Harmful Information on Facebook and Other Social Media: A Brief Report](https://onco.cc/key-papers/paper-johnson-j-natl-cancer-inst/)

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