Meta-analysisindependent cross-checkabstract checked I-CAN-103 standard review
Ketogenic diets in cancer patients: some metabolic benefits
Impact of ketogenic diets on cancer patient outcomes: a systematic review and meta-analysis.
Overview
Zhang M et al.. Front Nutr 2025 · PMID 40756563 · DOI 10.3389/fnut.2025.1535921
Ketogenic diets lowered body fat, insulin and glucose and improved some symptoms; survival was not shown to improve.
Does the study support the specific claim? Partly · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Effect of ketogenic diets in cancer patients.
- How was the study done?
Systematic review and meta-analysis.
- How many people, animals or samples were studied?
Cancer patients in controlled studies.
- What was actually found?
Better metabolic and some quality-of-life measures.
- How large was the observed effect?
Not quantified in abstract.
- What do the results mean in everyday life?
A diet can affect how patients feel and some blood values.
- What are the study's limitations?
Surrogate outcomes; small studies.
- What does it say about Elawady's specific claim?
Does not show that a diet treats cancer.
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
That any diet cures or controls cancer.
Scientific in-depth review
1. Full reference
- Authors
- Zhang M et al.
- Journal
- Front Nutr
- Year
- 2025
- Identifier
- PMID 40756563 DOI 10.3389/fnut.2025.1535921
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Authors declare no conflict of interest
2. Research question
Effect of ketogenic diets vs non-ketogenic diets on outcomes in cancer patients
3. Study design and population
- Study design
- Meta-analysis – Systematic review and meta-analysis of controlled studies (PROSPERO CRD42024553878)
- Population
Cancer patients assigned to ketogenic or standard diet
- Country
International
- Period
not stated in abstract
- Sample size
number of studies not stated in abstract
- Inclusion and exclusion criteria
Studies comparing ketogenic diet with standard diet control in cancer patients
4. Methods and endpoints
- Exposure / intervention
Ketogenic diet (in included studies generally alongside standard cancer care)
- Comparator
Non-ketogenic diet
- Endpoints
Body composition, insulin, glucose, lipids, fatigue, quality-of-life domains, CRP
- Statistical methods
Meta-analysis
5. Actual results
- Results
Ketogenic diet reduced fat mass, visceral fat, insulin, blood glucose, fatigue and insomnia and improved some lipid, TSH and quality-of-life domains compared with non-ketogenic diets. No survival or tumour-control outcomes are reported in the abstract.
- Absolute risks
not reported in abstract
- Authors' conclusion
Ketogenic diet improved cancer patients' outcomes more effectively than non-ketogenic diets.
6. Strengths
- Registered protocol
- Two independent reviewers
7. Weaknesses
- Outcomes are surrogate/metabolic, not survival
- Abstract does not give number of studies or certainty
- Interventions were adjuncts, not replacements of treatment
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Abstract-level judgement; heterogeneity and small trials likely.
9. Assessment of the statistical interpretation
Positive conclusion rests on metabolic and symptom outcomes; it does not show tumour regression or longer survival.
10. Relevance to the specific claim
Best available 'supporting' evidence that a diet can change outcomes in cancer patients; it concerns a ketogenic diet used alongside standard care, not the Tayebat system and not replacement of treatment.
11. Independent contrary findings
I-CAN-104 (RCT-only meta-analysis) found insufficient evidence; ASCO (I-CAN-105) judged diet evidence very limited.
12. Transferability to Germany and Europe
Moderate.
13. Overall methodological judgement
Indirect, low-certainty support for diet as supportive care; no support for diet as cancer treatment.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | indirect |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Survival and tumour outcomes in adequately powered RCTs.
15. Linked fact checks
- Cancer will respond to the Tayebat system; a patient with a malignant tumour should start the system now (diet as cancer treatment). – Studies with mixed or unclear results
- The idea that 'sugar feeds cancer' should be dropped: sugar feeds every cell (and microbe), so cancer patients need not fear sugar. – Studies with mixed or unclear results