Could a keto diet help you during cancer treatment?
In order to show you the benefits of a keto diet, it’s important that you understand the latest theory on the way cancers start. If you haven’t read the first in the series, begin reading here.
The latest research on keto diets and cancer
The first research on keto diets for cancer focused on glioblastoma, a type of brain cancer. A recent analysis of 41 studies found that the median survival time of patients on a keto diet more than doubled. After 3 years, 2/3 of them were still alive (1). To put that in perspective, with regular treatment alone, median survival time for glioblastoma is 14.6 months, and the 2-year survival rate is 26.5%, so the results on keto were a significant improvement.
An earlier animal study on neuroblastoma, another type of brain cancer, similarly showed that a keto diet and/or calorie restriction significantly reduced tumour size and prolonged survival (2).
A trial on later stage breast cancer patients undergoing chemo, found the keto diet to be safe. The participants lost some weight, which helps with survival in breast cancer. The weight was mostly fat loss rather than muscle. Muscle loss can be a sign of cachexia, which can be dangerous in cancer patients. They also discovered that the patients’ response to radiotherapy and chemo improved (3).
A later trial by the same researchers was a 12-week study on a similar group of later stage breast cancer patients receiving chemo. Their tumour size halved, and their insulin and insulin-like growth factor levels dropped. Higher levels of insulin and insulin-like growth factor stimulate cancer growth. And in patients with locally advanced disease, their cancer stage dropped significantly. Their inflammatory markers also decreased. The effects on metastatic disease were inconclusive, and the researchers suggested they needed to conduct larger trials to establish whether the diet helped (4).
A review of trials on breast cancer patients using a keto diet confirmed the diet reduced tumour size, improved the effects of chemo and quality of life, and was safe and tolerable for participants. As part of their research, they also discovered that in animal models, it reduced drug resistance and improved chemo effectiveness in cancers of the bladder, pancreas, and endometrium, as well as breast cancer and acute myeloid leukaemia (4).
There is promising evidence that a keto diet may help in endometrial and ovarian cancer in humans. Both types are highly sensitive to high insulin levels, so it makes sense that reducing them will help curb the cancer (5). However, another study found that in endothelial ovarian cancer, a particular type of ovarian cancer, a keto diet without calorie restriction encourages tumour growth (6). So, if you have endothelial ovarian cancer and decide to go on a keto diet, make sure you’re comfortable reducing your calories and losing some weight.
There is also emerging evidence that a keto diet could be useful for colorectal cancer (7), head and neck cancer (8), prostate cancer (9) and lung cancer (10). These were laboratory and animal trials, which may not translate to humans, so they are promising, but we can’t be sure that they’re helpful yet.
Safety considerations for cancer patients considering a keto diet
Although there is some evidence that a keto diet could stop liver cancer growth, the liver produces ketone bodies, which you generate to get energy from high-fat foods. So, if cancer has damaged your liver, you may not produce them, which would leave you with severe fatigue. That also applies if you have liver metastases.
If you have cachexia, a condition that causes loss of muscle weight that is common in advanced disease, it may be unwise to follow the keto regime. It could increase weight loss if you reduce your calorie intake.
You should discuss your diet plans with your treating team. They can advise you on how to plan it, as well as whether it’s suitable for you.
This article covers some myths around eating the keto way. It may answer your questions, with ideas on how to plan your meals, track your macros (calories/kJ, carbohydrates, protein and fat), and even some helpful websites where you can find good articles and wonderfully tasty recipes.
Conclusion
A keto diet may be helpful for you. Or you might prefer something more traditional, like the Mediterranean diet, which is also helpful for cancer patients and a good choice if keto is not appropriate for you.
Diet is not the only way to support yourself during cancer treatment. There are also lifestyle changes that can help a great deal, as well as supplements and herbs. You can find out all about those in my book, Naturally Supporting Cancer Treatment. Learn more here.
If you have enjoyed this article, you can sign up for my Treatment Support newsletter to get an article sent to you each month. As a thank you gift, I’ll send you a free booklet on soothing side effects. Learn more here.
If you’re more interested in articles about cancer prevention, I have another newsletter that goes out each month covering that. The thank you gift for that is a collection of recipes aimed at cancer patients (not keto). Click this link to find out more.
References
Firdous J, Asif AE, Haris HM, et al. Efficacy and safety of ketogenic diet in glioblastoma: An updated systematic review and meta-analysis. Neurological Sciences. 2026;47(5). doi:10.1007/s10072-026-09035-y
Morscher RJ, Aminzadeh-Gohari S, Feichtinger RG, et al. Inhibition of neuroblastoma tumor growth by ketogenic diet and/or calorie restriction in a CD1-nu mouse model. PLOS ONE. 2015;10(6):e0129802. doi:10.1371/journal.pone.0129802
Khodabakhshi A, Akbari ME, Mirzaei HR, Mehrad-Majd H, Kalamian M, Davoodi SH. Feasibility, safety, and beneficial effects of MCT-based ketogenic diet for breast cancer treatment: A randomized controlled trial study. Nutrition and Cancer. 2019;72(4):1-8. doi:10.1080/01635581.2019.1650942
Jemal M, Molla TS, Asmamaw Dejenie T. Ketogenic diets and their therapeutic potential on breast cancer: A systemic review. Cancer Management and Research. 2021;Volume 13:9147-9155. doi:10.2147/cmar.s339970
Cohen CW, Fontaine KR, Arend RC, et al. A ketogenic diet reduces central obesity and serum insulin in women with ovarian or endometrial cancer. The Journal of Nutrition. 2018;148(8):1253-1260. doi:10.1093/jn/nxy119
AlHilli MM, Rhoades EE, Chau D, et al. Unrestricted ketogenic diet feeding enhances epithelial ovarian cancer growth in vivo. Nutrients. 2023;15(12):2730. doi:10.3390/nu15122730
Tamraz M, Al Ghossaini N, Temraz S. The ketogenic diet in colorectal cancer: A means to an end. International Journal of Molecular Sciences. 2023;24(4):3683. doi:10.3390/ijms24043683
Klement RJ, Sweeney RA. Impact of a ketogenic diet intervention during radiotherapy on body composition: V. final results of the KETOCOMP study for head and Neck Cancer patients. Strahlentherapie und Onkologie. 2022;198(11):981-993. doi:10.1007/s00066-022-01941-2
Murphy S, Rahmy S, Gan D, et al. Ketogenic diet alters the epigenetic and immune landscape of prostate cancer to overcome resistance to immune checkpoint blockade therapy. Cancer Research. 2024;84(10):1597-1612. doi:10.1158/0008-5472.can-23-2742 Zahra A, Fath MA, Opat E, et al.
Consuming a ketogenic diet while receiving radiation and chemotherapy for locally advanced lung cancer and pancreatic cancer: The University of Iowa experience of two phase 1 clinical trials. Radiation Research. 2017;187(6):743-754. doi:10.1667/rr14668.1
