Keto and Cancer: Where Do We Stand?

The ketogenic diet has exploded in popularity over the last few years. Hordes of people are using it to lose body fat, overcome metabolic diseases, improve their endurance performance, attain steady energy levels, make their brain work better, and control seizures. And increasing numbers of researchers and personal experimenters are even exploring the utility of ketogenic diets in preventing and/or treating cancer. After all, back in the early part of the 20th century, Warburg discovered an important characteristic of most cancer cells: they generate their energy by burning glucose. If a particular cancer loves glucose, what happens if you reduce its presence in your body and start burning fat and ketones instead?

It’s taken a while, but the research community is finally beginning to take a few swings at this and similar questions.

So, what do we know?

First, let’s just go through a few recent human studies and case studies.

Keto and Cancer Treatment

Women with endometrial or ovarian cancer improved energy levels, appetite, and physical function on a ketogenic diet.

A Bayesian approach to studying the effects of ketogenic diets in humans and animals with high grade glioma (a brain cancer) found an “overall survival-prolonging effect.”

In gliomas, an analysis of available case studies using ketogenic diets found increased overall or progression-free survival. These were not randomized controlled trials, however, so they say nothing definitive.

A recent review paper gives a good overview of the current state of ketogenic diet and cancer research, finding that:

  • Ketosis targets tumor metabolism.
  • Ketosis improves effectiveness of conventional therapies.
  • Ketosis has favorable effects of anti-cancer gene expression.

One thing you might notice is that there are no studies showing that standalone ketogenic diets cure cancer. There aren’t very many randomized controlled trials in general.

What there are are studies showing that ketogenic diets are safe and potentially effective adjuvant treatments—treatments that supplement conventional cancer treatments. You don’t see keto “defeating” cancer alone. You see keto enhancing the effect of chemotherapy. You see keto enhancing the effect of radiation. You see keto protecting normal cells and increasing the vulnerability of cancer cells to conventional treatment.

That’s not to say that keto can’t beat cancer. Maybe it can. But the clinical research simply isn’t there to say one way or the other.

Where keto seems even more promising is in prevention of cancer.

Keto and Cancer Prevention

Diabetes is a disease of carbohydrate intolerance. It’s a disease in which carbohydrate consumption results in elevated blood sugar, exaggerated insulin response. The way most people with diabetes eat leads to chronically high levels of insulin and blood sugar. Yeah, yeah, I know about all the badass Primal eaters who are “technically” diabetic but keep their blood sugar pristine and insulin minimized by watching what they eat, exercising regularly, and just generally leading a healthy lifestyle—but those people aren’t a large enough a group to have an effect on the category known as (and studied as) “diabetics.” Most people with diabetes unfortunately keep eating the same junk that got them there.

What does research say about the cancer rate of most people with diabetes? It’s usually higher.

One of the most consistent risk factors for many types of cancer is having diabetes and experiencing all the metabolic fallout that entails—high fasting insulin, insulin resistance, elevated blood glucose. Cancers of the liver, pancreas, breast, endometrium, bladder, and kidney all have strong associations with type 2 diabetes. This should come as no surprise. Not only do many cancers thrive on glucose as fuel, the high insulin levels typical of people with diabetes and insulin resistance increase the availability of growth factors that promote cancer growth.

Meanwhile, therapies that are known to reduce the symptoms of diabetes—lower fasting insulin, increase insulin sensitivity, normalize blood sugar, etc—tend to lower the risk of cancer. A perfect example is metformin.

Metformin activates AMPK, the same autophagy pathway activated by exercise, fasting, polyphenol consumption, and reduced calorie intake. It lowers blood sugar, increases insulin sensitivity, and extends the lifespan of type 2 diabetics.

Metformin also seems to protect against cancer. It lowers hyperinsulinemia and may protect against insulin-related cancers (breast, colon, etc). Early treatment during adolescence, for example, protects rats against later tumor growth.

What does this have to do with ketogenic diets?

Ketogenic diets have many similar effects. They activate AMPK. They lower blood sugar. They’re great for fat and weight loss, which enhances insulin sensitivity. Recently, researchers have even used ketogenic diets to resolve type 2 diabetes.

Now, not all cancers are linked to diabetes. For example, diabetes doesn’t increase the risk of gastric cancer. That’s because it’s linked to bacterial infection, not elevated blood sugar. And that’s why taking metformin doesn’t reduce the risk of gastric cancer. This actually supports my hypothesis that, when diabetes does not increase the risk of a cancer, neither does metformin reduce it—like gastric cancer. Diabetes doesn’t increase it, so metformin doesn’t reduce it. That’s the mechanism in play.

Nor do all cancers burn glucose exclusively. Some thrive in a ketogenic environment.

There is a mutation called BRAF V600E in certain cancer cells that allows them to utilize ketone bodies to stimulate growth. About 50% of melanoma, 10% of colorectal cancer, 100% of hairy cell leukemia, and 5% of multiple myeloma cases exhibit the ketone-utilizing BRAF V600E mutation. Indeed, a cancer cell’s inability to break down and metabolize ketone bodies is the best predictor of whether a ketogenic diet can even help against a given cancer.

But if we’re talking prevention. If we accept that not developing diabetes—all else being equal— probably reduces the risk of getting cancer, then using ketosis to improve all the same symptoms linked to diabetes should also reduce the risk of getting cancer. And if it doesn’t reduce the risk, it probably won’t hurt. I mean, is there a doctor alive who claims that increasing insulin sensitivity, lowering hyperinsulinemia, and losing body fat will increase the risk of cancer?

A Few Takeaways To Consider

As I see it—and this is not medical advice—the most promising use of ketogenic diets in cancer are as follows.

Adjuvant therapy: Using ketosis to enhance the efficacy of conventional therapies like chemotherapy and radiation, increasing the susceptibility of cancer cells to treatment and increasing survival of healthy host cells.

Prevention: Using ketosis (whether intermittently or long term) to lower fasting blood glucose, reduce diabetes risk (or resolve extant diabetes), and improve your ability to burn fat and not rely on exogenous glucose so much should in theory reduce your risk of most cancers.

Whatever you do, if you’re an actual cancer patient, discuss this with your doctor. Make sure your particular variety of cancer isn’t partial to ketones. Make sure it’s one of the cancers that actually craves glucose. If you end up with a cancer that thrives on ketone bodies, and you go deep into perpetual ketosis, you could be making an enormous mistake.

But the bottom line is that, assuming you don’t already have one of the cancers known to utilize ketones, going into ketosis from time to time isn’t going to hurt—and it will probably help reduce the risk of cancer.

I’m going to close this post with an anecdote from one of my employees. His father passed away a dozen years ago from multiple myeloma, a type of white blood cell cancer. This was before he worked at Primal Nutrition; he was just getting involved in alternative forms of health and nutrition research. What struck him most, particularly in retrospect, was how his father’s appetite changed during his battle with cancer. He began craving candy—Reese’s peanut butter cups, Hershey’s kisses, Now-and-Laters, and all other kinds. As he says it, looking at his dad’s snack drawer was like looking at the archetypal bag of Halloween candy.

I don’t know if this is evidence of anything. Can cancer actually tap into your specific appetites? Can it change how you perceive and desire specific foods? Was his father actually being programmed by his cancer to over-consume sugar?

Who knows.

What I do know is that no one needs garbage candy. A few seconds of momentary gustatory pleasure, followed by regret and the incessant need to repeat—is it worth it? Is it worth the off chance that eating lots of sugar feeds and promotes cancer? Don’t do it, folks. I know my longtime readers are right there with me. I know you guys who’ve been here from the beginning are probably getting egged on Halloween because you’re giving out collagen packets and mini-kettlebells. But if you’re new to this site and way of eating in general—maybe a co-worker passed my info along to you, maybe you’re trying to make a big change in the way you eat and live—avoiding the obviously terrible-for-you stuff like candy and baked goods is the biggest change you can make. And not just for cancer.

So, do I want you to walk away from this post thinking that keto is a cancer cure? No. I’m a fan of ketosis, and I think almost everyone should spend time in that metabolic state, but I don’t consider it to be magical. The jury is definitely still out. Does ketosis look like a strong candidate for improving efficacy of various therapies in certain cancer patients? Yes. Can keto improve health markers shown to reduce a person’s risk of getting cancer in the first place? Yes.

The keys to good health are generally speaking pretty consistent. 

There’s no guarantee against cancer, but I think the advice I just mentioned supports a good fighting chance.

Take care, everyone. Be well.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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39 thoughts on “Keto and Cancer: Where Do We Stand?”

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  1. I know it’s a 1-1 study, but my husband DID beat stage-3 prostate cancer using keto, and without the use of “conventional” therapy.

    He did use alternative treatments such as suppository use of cannabis, CBD, and certain detox protocols. But, no chemo, radiation, or lupron (chemical castration).

    MRI confirmation (same facility) showed that the cancer was completely gone within 6 months. Followup MRI 6 months later show that it is still gone.

    BTW, he did not do “dirty” keto. Only grass-fed meats, organic chicken, wild caught fish, and lots of organic veggies. He used grass-fed ghee, but no other dairy. He also did some juicing, and still drinks a green juice daily.

    Hope this helps someone else. The cancer diagnosis can be very scary. Plus, at least in our case, the urologist did his best to intensify that fear. Thankfully, our insurance company did not approve the lupron treatment right away. And, while waiting for approval, we had time to explore other options (outlined above).

    1. Thank you so much for posting, my husband just got diagnosed too. Your post gives us new hope, I have been doing keto for a year and have seen the health effects first hand will now convince my husband.

    2. Mari Ann – what a great story! I was diagnosed with cancer of the appendix 4 years ago. Had MOAS (Mother of All Surgeries) and a warm chemo wash while in surgery. Started eating keto and lots of exercising. One more year and I will be considered cancer free. I continue keto and intermittent fast and I feel great!

    3. I’m glad your husband beat his cancer. But I know from having worked in a huge seniors program that the results of alternative therapies are almost always failures. I’ve heard more than a person or two express regret that they didn’t listen to their doctors, as they had by then gone too far. Dying.

      My best friend went through a prostate cancer therapy. He used an oncologist, urologists tend to want to do surgery. He was on Lupron, there is nothing wrong with that, despite your emotional tag of chemical castration. He lost some libido for awhile, but it came back.

      Don’t reject conventional medicine out of hand. A short list of how it has made my life longer and more effective includes getting one of the first Salk polio vaccinations in the world, cataract operations, and a knee replacement.

      1. OnTheBayou thank you for your reply. I am a stage 3 breast cancer survivor, newly in remission, and also a longtime Primal/Keto enthusiast. There’s no way in hell I would have ever rejected chemo and radiation — they saved my life and continue to do so. I am also on Lupron. Posts like these that tout “alternative therapies” do patients a huge disservice. It’s like Mari Ann Lisenbe didn’t even read Mark’s post at all. Anyway, thanks.

        1. Did you miss the part that advises one to seek professional advice ??? You can’t hope to think that theSAD diet is good for anyone, least of all cancer victims ?!

      2. What about my grandfather and my mother? They didn’t do anything alternative and died from cancer and their radiation and chemo treatments. The radiation and chemo made their deaths more agonizing than if they had just died from cancer.In truth I meet more people who had a relative die from chemo and radiation than I met people who have relatives who died from not treating their cancer.

      3. Many people were duped by the Salk vaccine. Even Salk admitted it’s failure. Glad you’re still healthy.

    4. People. This is why anecdotes and associations do not constitute reliable data. It’s quite possible your husband beat the cancer despite the keto. Associations are just historical facts. But the main fact that remains is however you want to handle your disease, barring those few cancer types Mark gave, eating right makes you healthier and healthy people generally fare better.

    1. You can just hand out pig knuckles. They also serve as decoration!

  2. Great post Mark. You are so right about the cancer hijacking someone’s tastebuds to crave sugar. My mother died last year from metastatic breast cancer, and was doing really well in the first few years following the diagnosis: and was reading up on all the supplements to take etc and to avoid sugar. In the last year of her life though the cancer literally seemed to have hijacked her brain: causing her to forget all she had learned over the previous 8 years and start craving sugary sweets. She even once called down for me to give her a spoon of sugar. Very frightening – because believe me if it can happen to someone as aware of the dangers of sugar as my mother was, it could happen to me – or to you…

    1. Same thing happened to my mom when she was diagnosed. When she was doing chemo all regular food tasted bad to her, but the docs were on her to keep her weight up, so encouraged her to eat whatever she could tolerate. She once went out to eat with dad and ordered two pieces of pie for lunch. And that trend continued til we lost her.

  3. I was diagnosed with breast cancer in April at 47. I was in the best shape of my life, had none of the risk factors or family history, and have been a huge fan of Mark for over 10 years, experimenting with Keto, intermittent fasting, etc.

    My point is that cancer does not discriminate. You can do everything “right” and still get cancer, however, I’m happy to say that I am kicking cancer’s ass. I’ve been able to continue exercising throughout my treatment and feel as strong and fit as ever. My last chemo treatment is Monday, Oct 14th.

    I have read countless research studies over the last 7 months and in my opinion, there is just not enough research and too much conflicting information for me to dive Into Keto to manage my disease going forward.

    Every cancer is vastly different, and every body responds differently to treatment – conventional or otherwise. It is an extremely complex group of diseases with multiple genetic, metabolic and immunological factors. And like Mark says, you must determine whether your particular cancer would respond positively or negatively to a ketogenic diet.

  4. Thank you for this information. I am currently in chemo and already planned to talk to my doctor. I do have a question for Mark. I had my gall bladder removed, do you have any suggestions for making the Keto diet more agreeable?

    I eat low carb and as primal as I can. Plus I usually fast except for a 2-hour eating window. After trial and error, that just worked best for me.

    And the desire for sweets is overwhelming while on chemo. I’ve resisted mostly but it’s double tough. Thank goodness I’ve got nearly ten years of habits under me. And still, it’s difficult to not eat sweets.

    I wrote a success story about weight loss and general fitness several years ago when I started this battle with cancer. I believe that Mark’s work continues to a huge difference in my quality of life. I’ve just got to put my disease in the rearview mirror.

  5. Sure wish my old friend, Terence McKenna, knew about keto when he was diagnosed with brain cancer.

  6. Cancer uses many metabolic pathways ( think of an elaborate subway system) One of those pathways is glucose but if it cannot find glucose cancer can easily utilize fat (as is the case with prostate cancer) or switch over to glutamine so the article is somewhat simplistic and cancer is anything but.
    I suggest reading Jane McLelland’s book “How To Starve Cancer as a great starting point.

  7. I am a big fan of the Ketogenic Anti-cancer diet.
    I used it to cure my prostate cancer. I have
    testimonials on my web site of people that have
    cured braiñ cancer and breast cancer.

    I have used Essiac to cure leukemia in an ex-wife
    and a cancerous bone cancer in my cat.

    I would NEVER submit to chemo or radiation to
    to support the Cancer Industry which includes
    the pharmaceutical companies that supply
    these dangerous and largely infective
    chemo drugs.

  8. I went to see a xray radiologist to discuss
    that method if treatment I was telling him
    about the Ketogenic diet and he told me
    with a straight face that diet would have no
    impact on cancer curing. The meeting
    did not end well. 🙂

  9. Chemo and radiation are the standard treatments for cancer of any kind. If radiation was good for people, Japanese citizens who were bombarded at Hiroshima would have survived and lived long, healthy lives. Same as the citizens of Chernobyl. Radiation cures no one. It is deadly. Chemo also destroys healthy cells. The numbers of cancer survivors using these standard treatments, are not high enough to herald them as being the ultimate cancer cures. While they may send cancer into remission for a short time, THEY DO NOT CURE IT!!

    1. Elizabeth, that is one of the stupidest comments I’ve ever seen published here. That covers ten years. Radiation treatment works because of exactly what you say: It kills cells. Radiation treatment for cancer focuses the rays to the unwanted cells. Alternatively, and as my friend got, little radioactive rice sized pieces put in his prostate.

      Further, your statement that conventional therapies is “not high enough to herald them,” is just flat outright wrong. Cancer survival rates have gone up and up due to these therapies. Do they always work? No. But what does 100%, other than death itself.

      Please get better informed before you spout lies and claptrap.

      1. It occurs to me that both of you might be plants attempting to start a flame war. However, it’s possible that Elizabeth is a person with an actual cancer diagnosis and you’ve just called her personal medical decision stupid, a decision that is probably life or death, and certainly none of your business. Even in cancer treatment the wishes of the patient must come first. So I think you owe her an apology.

      2. Why are you so nasty? Many of us have watched chemo harm rather than help. All opinions welcome. I do think the bombing comments were unfounded

  10. Keto is good for most cancers but not for all. I don’t have the data handy but I definitely found some studies about some cancers that love ketones. I think this article can be improved by doing that research and listing the cancers that like keto.

  11. I’m a researcher in cancer metabolism (go Otto Warburg!), so I was super curious how this post was going to go. I appreciate all your posts for how you always give the scientific studies (+ links) that support what you say. This one is no different. I am really happy to see you are coming from a standpoint of the general health benefits of a ketogenic diet and it not being a targeted cure. My one comment is that even if the cancer is the type that ‘craves’ glucose, avoiding it is not going to starve it (I know you don’t say this specifically, but just to make sure readers understand that). While an (unhealthy) body may exist with consistently increased blood glucose, as in the case of diabetes, you won’t find consistently decreased blood glucose in any functional person. The body will produce and maintain the necessary concentration of glucose if you aren’t consuming enough of it.

    Keep up the good work – I love reading your stuff 🙂

  12. When I was on chemo (colon and bladder cancer) I lost my sense of taste except for sweet. Everything else was flavorless. It’s hard to eat what you can’t taste. I found I could somewhat taste pickled herring so that was a big part of my diet.

    My cancer included getting a high output loop ileostomy to give my colon time to rest and heal. The high output ileostomy prevented me from getting back to PB, keto, and IF because keeping it happy required a low fiber hi-carb (think crackers, bread, potatoes, and other starchy foods) in order to prevent diarrhea, dehydration, and mineral depletion.

    I had the ileostomy for 7 months before reversal. Between the ileostomy and chemo I ended up with severe side effects and metabolic syndrome. Now I am gaining weight like crazy. I figured I would get back to keto, but it’s just too extreme right now. Like one of Mark’s success stories, portion controlled PB with IF is my plan.

    I believe my cancer was caused by a combination of (1) a family history of cancer and bad genes gave me a 50-50 chance of getting it and (2) high stress. Right before I was diagnosed I sold my old home and moved into my new home and my sister was diagnosed with stage IV pancreatic cancer. Diet wouldn’t have prevented my cancer, but being keto before the diagnosis may have made my recovery faster and easier than most.

    Today I am alive and bag free and, so far, cancer free because I have a great team of doctors. I wouldn’t be here without them.

  13. Great information! I am glad you distinguished between the cancers who thrive in an environment filled with glucose as opposed to an environment filled with ketones.

    1. People interested in metabolism and cancer should read the books and listen to the talks/podcasts by Dr. Nasha Winters. She has the most comprehensive view and wealth of patient experience using metabolic therapies with cancer that I have come across. One of the things she emphasizes (I think this is in her talk with Dave Asprey, as well as possibly Robb Wolf) is that a Ketogenic diet has many anti-cancer methods of action beyond ketones, and that in her experience, a ketogenic diet is good to combat ALL cancers including those that burn ketones. I think Mark and several others here have fallen into the simplistic “starve the cancer” trap when in fact the “starvation” aspect is fairly minor with diet alone, and there are many other mechanisms in play as Dr. Winters details, so saying to avoid ketosis for ketone-burning cancers is probably wrong when done in the context of a holistic metabolic program. Dr. Seyfried’s press/pulse approach is also relevant here.

  14. The kindest thing I can say about oncology is that I eagerly await the day when keto can stand alone in the treatment of cancer. And there’s a moratorium on toxic cancer drugs. That’s my deepest prayer based on experience. No person should ever have to go through the trials of cancer treatment as it stands today.

  15. Hi Mark
    Derek passed away in March from acute myloid leukemia. We had been hiking in the Alps in July of last year and when we returned from holiday, he was diagnosed with leukemia. Within 6 months he was gone. We have been on a ketogenic diet for ten years but in the last two months of life, Derek began craving sweets. I believe that the craving was from the cancer.
    You were an inspiration to him. Derek enjoyed attending two Primalcons in Oxnard and the one in Mexico. I believe that if it hadn’t been for the primal lifestyle, he would have had cancer years earlier. Proper diet and exercise should be the first line of defense for any disease.

    1. Barbara, I’m so sorry to hear about Derek’s passing, but I appreciate you sharing it with me and the MDA community. Life (and the end of it) will always be something of a mystery, but I’m heartened to hear that Derek was able to live a vibrant, active and expansive life–and that his diet helped him extend his time to enjoy it to the fullest. Condolences and gratitude from all of us on the Primal team to you and your family. – M

  16. Will toss this out there … from what I’ve read over the years medicinal mushrooms are one of the best adjuncts to a healthy lifestyle in potentially helping to prevent cancer or as part of a comprehensive approach in treating. To those of you battling cancer, all the best and much positive energy and love your way, and condolences to those who have lost loved ones to this scourge.

  17. The Mari Ann/Marion exchange above kind of made me think there should be a place where people can share and answer questions about the difference Primal and Keto have made in their lives. And then I remembered that place used to be the fora on this site, which were… upgraded… to Facebook. Are you looking at how that change is affecting discourse?

  18. This is unrelated to this post but I am desperate! Mark, do you have any advice for overactive bladder or Nocturia? It seems that following keto makes it so much worse for me and I dont know why. I had to stop following keto due to this because eating more carbs lower the amount I am peeing. I obviously hold more water and look a little swollen (also gained weight) so i am not in a fat burning mode anymore. I thoroughly enjoy eating keto but waking up 6-7 times a night to pee has made it impossible for me to stick to after several years so I stopped keto this year. It just kept worsening. I would love your thoughts or any recommendations.

  19. I found this article so interesting, especially the info on cancers that crave sugars. Great info, as usual. Thank you.

  20. Talking about “starving cancer” is utter foolishness! There is no such thing as “cancer cells”.

    Any cancer tumor is the cellular attempt to encapsulate an aggressive Candida albicans tissue invasion. Nothing stops this except dousing the interior of the tumor with pure sodium bicarbonate.

    Chemo and radio don’t cure cancer because they don’t kill the Candida that causes the tumor. Neither would any diet succeed unless the tumor capsule were first punctured and the Candida destroyed using NaHCO3.

    Cancer is only successfully cured when treated like a parasitic infestation (like tapeworm or liver fluke cysts) because that’s similar to how a Candida infection provokes tumors in organs and deep tissues.

  21. As a Type 1 diabetic, I do find this line pretty offensive as not all diabetics (like Type 1) get it because of eating habits — “Most people with diabetes, unfortunately, keep eating the same junk that got them there.”

    Don’t lump us all together. If you are educating people, be informed.

    1. Oh, come on. Mark’s context makes 100% clear he is talking about Type II’s, and in my experience he is spot on. Why can’t you say or add something constructive or positive when someone is providing free information that doesn’t get enough publicity instead of looking for things to twist the meaning of into something “offensive”.