In a March 2018 Q&A Dr Rhonda Patrick tackled the following question (source):

What are the immediate, most powerful steps we should take upon getting a cancer diagnosis, and, what traditional medicine protocol should we be wary of that may in fact possibly do harm?

Before answering, Rhonda was quick to say that anyone diagnosed with cancer should consult with their oncologist regarding treatment information they get from anyone, anywhere. And thus what follows is not medical advice, rather, its her personal, hypothetical, approach to the question.

Below is a summary of the key things Rhonda would do, and the key things Rhonda would avoid if she got cancer. Under that are more lengthy explanations as to her rationale.

Here are the key things she would do:

  1. Utilize fasting or the fast mimicking diet – which sensitizes cancer cells to death, and increases the stress capability of healthy cells to chemo/radiation
  2. Optimize her gut microbiome – which boosts the immune system in fighting cancer
  3. Supplement lots of broccoli sprouts – sulforaphane in broccoli sprouts has many similar effects to fasting; sensitizing cancer cells to death & increasing stress capability of healthy cells to chemo/radiation
  4. Increase exercise – again, has similar effects to fasting and sulforaphane

These are the key things she would avoid:

  1. Avoid animal meats; going on a more plant based diet – to reduce IGF-1 signalling, which can allow cancer cells to survive under stressors such as chemo/radiation
  2. Avoid high doses of supplemental antioxidants – such as vitamin A or C – which can reduce effects of fasting, exercise and sulforaphane
  3. Avoid all opioids – such as morphine, fentanyl, vicodin, oxycodone etc – These increase cancer metastasis
  4. Avoid the ketogenic diet – risk that ketogenic diets could be harmful depending on the type of cancer

Expanded details on what Rhonda would do if she had cancer

Below I’ve paraphrased and, where useful, elaborated/clarified on Rhonda’s thoughts from her March 2018 Q&A video – where she tackled the question of what to do with a cancer diagnosis:

Utilizing Fasting or the Fast Mimicking Diet

The Prolon Fast Mimicking Diet (FMD) kit, developed by Valter Longo and his colleagues

Fasting and the Fasting Mimicking Diet (Prolon) has been shown in preclinical studies, meaning animal studies, that it can sensitize cancer cells to death. Additionally it can increase the robustness and stress response pathways of normal cells. This has particular relevance for any standard of care treatment like radiation or any type of chemotherapy drug, which is very toxic to not only cancer cells, but to normal cells. See this pre-clinical study by Valter Longo et al. demonstrating fastings effect of sensitising cancer cells to radio and chemotherapy.

So, when you’re able to increase stress response pathways of normal cells, they’re able to take on more toxic dose of stress from, for example, radiation or chemotherapy.

And, amazingly, there were less of the side effects of the neutropenia, which is a common side effect. Neutropenia basically means that there’s a decreased number of white blood cells and also red blood cells and platelets. The reason that happens is because the chemo kills off those blood cells in addition to potentially killing cancer cells, and this was less likely to occur in people that did a 72-hour fast before doing the chemo.

If we think about it, based on the mechanistic studies in animals, because of the increased stress response pathways in the blood cells, those cells had increased antioxidant pathways, anti-inflammatory pathways, preventing them from being stressed, like from chemotherapy.

Illustration of the potential pathways up-regulated and down-regulated when fasting in normal & tumor cells – via Michelson Research Foundation

Its been shown by Dr. Valter Longo and colleagues in a couple of studies: one with a just water fast, a 2-3 day water fast, and also one with the fasting mimicking diet that it was safe for people that were undergoing chemotherapy to do.

That being said, Valter Longo and his colleagues are not saying that they have explored every eventuality when it comes to fasting + cancer + chemotherapy/radiotherapy. It’s entirely possible, unlikely, but possible that fasting actually worsens certain types of cancer. Until fasting has been tested in 100+ types of cancer, we can’t know for sure. Their team are gradually doing these studies, but they are expensive and take time.

For now, Valter discusses this therapy (fasting + chemotherapy/radiotherapy) as something that people could try (under the supervision of their oncologist) for cancers where there is not an existing, successful method of treatment, and the options look slim. But the hope is that as more studies are performed, and its tested in more cancers, they will be able to recommend it for these.

In terms of the details around the fasting regimen they are testing, it’s 3 days pre chemotherapy/radiotherapy and 1 day post. Although, because many people struggle with water only fasts, for various reasons, they are working on a fast mimicking diet specific to this treatment. Their original FMD is called Prolon, and this new one for Cancer will be called Chemolieve.

Optimizing The Gut Microbiome

Multiple preclinical studies have shown that the microbiome plays a huge role in regulating the immune system.

There have been preclinical studies where animals were given large doses of probiotics and then were injected with cancer cells, causing tumors to form, and, in fact, the probiotics were almost as effective as the standard of care chemo treatment in terms of killing and shrinking the tumor. Because these animals were completely changing their immune cell profile, they were making lots and lots of natural killer T cells and also cytotoxic T lymphocytes, which are two very important immune cells that play a role in killing cancer.

There’s been very little evidence looking at the effects of probiotics supplementation in cancer patients. There’s one study in patients that had colorectal cancer. If the cancer is in the gut, Rhonda suggests its probably even more relevant to make sure to optimize the microbiome. There was one study where people with colorectal cancer were taking around 300 billion probiotics a day, and it reduced their colorectal cancer recurrence. Likely because, again, they’re making more of the cytotoxic T lymphocytes and natural killer T cells.

Therefore Rhonda would personally be supplementing with a very strong probiotic, possibly multiple times per day, something like a Visbiome or VSL#3. Which are essentially the same, have the same composition of bacteria and also the same quantity, as they were formulated by the same physician. They come in 2 different versions; capsules, which contain 112bn live bacteria per capsule, and larger sachets, which contain 450bn. They get delivered in ice, as they’re live bacteria, and need to be kept refrigerated.

Supplementing Broccoli Sprouts (Sulforaphane)

Rhonda would be making lots of broccoli sprout smoothies, based evidence showing that sulforaphane, the active component of broccoli sprouts, can:

  • Reduce cancer recurrence
  • Kill cancer cells
  • Sensitize them to death

It actually does a lot of the same things fasting can do, in the sense that it sensitizes cancer cells to death and at the same time it also increases the stress resistance in normal cells.

Increase Exercise

Rhonda would ensure she’s doing good amounts of exerice, based on lots of preclinical studies and also human studies have shown that exercise really can shrink tumor cells.

It works similarly to fasting and sulforaphane, in that it sensitizes cancer cells to death because there’s an acute production of reactive oxygen species, which cancer cells can’t deal with very well due to their composition, and thus causes them to die.

It’s one of the main mechanisms by which chemo drugs kill cancer cells, but at the same time the exercise increases the anti-inflammatory antioxidant pathways in normal cells. This is one of the ways that exercise is so beneficial long term for longevity, because it ramps up these stress resistant pathways. So it’s really good for normal cells and not so good for cancer cells.

Rhonda uses spinning classes as high intensity interval training.

Expanded details on what Rhonda would avoid if she had cancer

Avoid animal meats; going on a more plant based diet

Rhonda would go on a more plant-based diet because of its ability to reduce IGF-1. Essential amino acids, which are more abundantly found in animal protein, can very powerfully activate IGF-1. IGF-1 does not cause cancer, but for someone that already has a tumor it can absolutely allow cancer cells to survive. It allows them to survive in the face of other stress inducing factor like chemo, radiation, sulforaphane, fasting, exercise – all those things.

What this means is, even if you’re doing all the “good stuff” Rhonda highlights above, if you’re consuming large amounts of amino acids (which are abundant in meat), these will increase IGF-1, which leaves a window of opportunity for cancer cells to survive.

Low protein has been shown in associative studies to reduce cancer risk & all cause mortality. However for those 65+ its important to consume moderate amounts of protein to maintain muscle mass – Image Source

Avoid high doses of supplemental antioxidants

On a similar note, Rhonda would also avoid supplemental antioxidants like vitamin E and vitamin C. In the past there have been mixed schools of thought with antioxidants and chemo/radiation. The pro-antioxidant idea was that by supplementing antioxidants alongside chemotherapy, you can help protect normal cells, whilst still killing the cancer cells. However, it appears that concensus is now swinging away from supplemental antioxidants (source).

Chemo/radiation induce a burst of reactive oxygen species to induce apoptosis (cell death). But with antioxidants already present in the cell, these can dampen the therapies effects.

It has been shown in mice that were given vitamin E or acetylcysteine, both of which are supplemental antioxidants, and then they were treated with a dose of chemo. In the animals that were given the supplemental antioxidants, the tumor cells did not die and the tumor even grew, which is concerning with respect to taking a supplemental antioxidant.

Rhonda points out that the antioxidants used in these studies are high dose, so taking like the RDA of vitamin E ( around 24 to 30 IU’s) is not going to do what taking 400 IU’s a day of vitamin E does.

Related to this are the studies of intravenous vitamin C, which appear to sensitise cancer cells to death. This works differently in mechanism to oral doses of antioxidants because much higher circulating blood levels are achieved than oral doses. To quote Rhonda:

“What ends up happening is that the vitamin C goes between being oxidized and reduced, and the oxidized form actually is what can help kill cancer cells because hydrogen peroxide is produced in small doses, in a similar way to fasting, sulforaphane & exercise induce a little bit of stress reactive oxygen species, the intravenous vitamin C does something very similar, which again sensitizes cancer cells to death and also increases stress response pathways in normal cells”

There’s been a hand full of clinical studies from Mark Levine’s lab out of the NIH showing that people that are doing standard of care along with intravenous vitamin C have better outcomes than people just doing standard of care.

Avoid All Opioids

Rhonda suggests that opoid painkillers are avoided, due to their ability to dramatically increase cancer metastasis (see this review).

Instead, she would be taking Meriva, a phospholipid version of curcumin. It’s been shown in a couple of clinical studies to be equivalent to 800 milligrams of Ibuprofen in terms of pain relief, and another study showed it equivalent to 1000 milligrams of Acetaminophen.

Rhonda personally takes it for headaches and menstrual cramps and says it absolutely helps with the pain.

Although she acknowledges that cancer pain can be on a whole other level, so this is an easier recommendation to say than do.

Example of a commonly prescribed opioid.

Avoid the ketogenic diet

The Otto Warburg metabolic theory of cancer, championed by Thomas Seyfried, looks at cancer as a metabolic disorder. With one of the key culprits in driving cancer being insulin. This has led to scientists like Thomas Seyfried and Dom D’Agostino testing the ketogenic to fight cancer.

However, Rhonda points out that cancer is more complicated than just a metabolic disorder. She acknowledges that the ketogenic diet has been shown to be beneficial for certain types of cancer, particularly the work coming out of Thomas Seyfried’s lab. However, she cautions against his particular mouse model of brain cancer, because of how responsive it is to the ketogenic diet. Contrasted with other animal studies that have shown the ketogenic diet can be harmful, as well as helpful.

Rhonda goes on to say that there are certain types of cancer that actually metabolize beta-hydroxybutyrate and use it as fuel. Additionally she notes that cancer cells love fatty acids. Fatty acids are really important to build new cells and so fatty acid metabolism is ramped up in a lot of cancer cells because it’s increasing the molecular biomass of making new cells.

She suggests that fasting, or the fasting mimicking diet may be a safer approach.

Rhonda notes that she is very familiar with the work of Thomas Seyfriend and Dom D’Agostino, and during her graduate study she was really following Thomas Seyfried’s work for a long time. But then she started to do a lot of experiments herself, and she was getting conflicting evidence.

Note from Alex (Blog Author): I was very suprised to hear Dr Rhonda Patrick explain that a ketogenic diet could be harmful in the presence of certain types of cancers. Like many people, I had heard good things about using ketogenic diets to battle cancer. And wanted it to be true that a simple diet modification (ketogenic diet) could defeat cancers.

I would be tempted to question her on this, but it sounds like she has been following the key expert in the field of ketogenic diets and cancer; Thomas Seyfried, who literally wrote the book on Cancer as a Metabolic Disease. Thus her info will be at least as good, and likely better than mine.

So the next logical question is… which cancers could ketones be bad for? Plugging “ketones” + “cancer” into Google Scholar leads to papers that explore beta-hydroxybuterate’s interaction with breast cancer. So there is at least some published work backing up this idea that ketones could be bad for certain types of cancer. Lets take a brief look at 2 of the papers…

Ketones and lactate “fuel” tumor growth and metastasis – Gloria Bonuccell et al. 2010
– The paper touches on how 3-hydroxy-butyrate (aka betahydroxybutyrate the ketone) in cells that model breast cancer.

Ketones and lactate increase cancer cell “stemness,” driving recurrence, metastasis and poor clinical outcome in breast cancer – Ubaldo E. Martinez-Outschoorn et al 2011
– This paper is by the same group as above, and this time looks at at mechanism for which ketones and lactate fuel cancer growth

There are a few things that stick out for me on this. Firstly, there doesn’t seem to be a good body of research on which cancers ketones “fuel”. I’d love to see a more comprehensive, research backed list. Secondly, I’d love a better resource for rating reputation of study authors. The journal the above papers are published in, Cell Cycle, certainly isn’t a major one – so it’s hard to know how to judge their research.

Keto friendly foods – may not be optimal for 100% of cancer types, given that some actively metabolize beta-hydroxybutyrate (a core ketone your body uses for energy whilst in ketosis)

Rhonda on Researching the “Standard of Care”

Rhonda suggests to heavily research the standard of care treatment you are recommended. What she means by that is for example with chemotherapy she would look at the type of cancer and how effective chemo is to treat it. There are a lot of cancers that are very responsive to chemo, particularly leukaemias and lymphomas, they’re very responsive to chemo because they’re blood cancers and chemotherapy works through the bloodstream. So if you have a cancer in the bloodstream, the chemo is going to be more effective at killing those cancer cells just based on the location.It can actually get there and kill the cancer.

However, the majority of cancers that adults get are solid tumors; prostate cancer, breast cancer, kidney cancer, liver cancer, pancreatic cancer, ovarian cancer. These cancers are solid tumors and they occur very far from the bloodstream and in fact a lot of tumors go what’s called hypoxic, meaning they find a way to survive without even the blood. Thus chemo is not very effective at delivering the drug to the cancer cell because it never actually makes its way there. Because the cancer cell has grown so far from blood vessels and you can’t actually get the drug there. Thus she recommends to reasearch and speak to the doctor.

Rhonda on CBD oil & THC

Rhonda notes, in answer to a question around CBD oil and cancer, that she has not researched much into CBD oil or THC (if THC is available to you), but she says they appear to be an up-and-coming modality for the treatment of cancer. In both their ability to modulate the immune system in such a way that its able to kill cancer cells, and also potentially as an alternative to pain medications.

CBD Oil in dropper form.

Support Rhonda

If you enjoyed this content, please support Rhonda at It’s fans like you and me who fund her continued research and content creation. It’s a massively time consuming task that she takes on, and it’s to all our benefit that she continues to source great interviews and brings cutting edge research to the mainstream.


Posted by Alex


  1. Rhonda says that you shouldn’t go on a ketogenic diet if you have cancer, because some cancers metabolize ketones. But then she says you should do fasting, but doesn’t fasting raise your ketones even more than on a ketogenic diet?


    1. Alex

      Hi Sam, thanks for your message.

      So with regards to cancer and fasting, I think Rhonda was specfically talking about using the fast mimicking diet. On this diet participants are consuming food (including carbohydrates) daily – which would limit how high your blood ketones can get. Typically it’s only after 3/4 days on a water only fast where we see super high blood ketone concentrations. With no glucose sources, it gives the blood glucose levels a chance to drop low, which is necessary for the blood ketones to then ramp up.

      The other thing about her fasting suggestion is that it would be sporadic, ie, you might fast for 5 days, but then not do that fasting cycle again for a week or longer. Thus, even if your ketones did increase over the fasting period, once you began eating normally again, they would then drop. Contrast this to a ketogenic diet, where your ketones remain elevated every single day.

      That way, even if you do a 5 day water only fast, you’ll only really have elevated blood ketones for 2-3 days of the fast. A lot less than if you were eating keto daily.


  2. “Avoid animal meats; going on a more plant based diet – to reduce IGF-1 signalling, which can allow cancer cells to survive under stressors such as chemo/radiation”

    A Keto (meat) diet REDUCES IGF-1!! Doesn’t Rhonda have it backwards?

    Understanding IGF-1 (Insulin-Like Growth Factor) in Simple Terms Dr. Berg


    1. Alex

      Hey. I believe the concern Rhonda has with the ketogenic diet isn’t due to IGF-1. With the ketogenic diet she is concerned that it may exacerbate the cancer, depending on which type of cancer one has. She points out that some cancers metabolize ketones (including betahydroxybuterate), and if you had one of those cancers, and went on the ketogenic diet in the hope of weakening it due to deprivation of exogenous glucose sources, you could be shooting yourself in the foot.

      Where we need to go from here is to be able to quickly diagnose whether or not you have one of those cancers. If your cancer thrives on glucose, great, we can limit exogenous glucose (for example through ketosis and/or other means, such as taking metformin). If your cancer however thrives on ketones, then we need to be careful not to increase them.


  3. Its well known in vegan circles that any meat including fish can potentially cause cancer. Meat protien is not the same as animal protien. Check check out and the china study if you dont believe me.


    1. Alex

      “Meat protien is not the same as animal protien.”

      Not sure what you meant by the above.

      In terms of what causes cancer – it’s anything that causes DNA mutations in cells – which is a long list. Including things like sun exposure, breathing car exhaust fumes and not getting enough sleep. Additionally, during cells division, errors can occur by accident. So really, DNA mutations are an ongoing risk to everyone.

      Generally speaking, our cells have built-in mechanisms to mitigate DNA mutations. Including a gene called P53, which fixes or removes mutations when it finds them.

      Getting mutations in the genes responsible for cleaning up mutations (like P53), is particularly bad.

      Long term solutions to cancer will involve advanced systems for gene editing.


  4. Hi Alex

    really helpful to have all this in one place as often views are changing with better understanding.


    1. Alex

      Hey Rick. Yeah, absolutely. Perhaps the two parts that stuck out the most for me were:

      – Cutting out meat -> I hadn’t realized IGF-1 was “strong enough” to keep cancers alive whilst applying stressors to them
      – Rhonda’s caution with regards to the ketogenic diet -> I had previously heard Dom D’Agostino say he would get on a ketogenic diet if he had cancer. So its good to know that there are cancers that can potentially thrive on beta hydroxybuterate. Cancer is so complicated! But perhaps rightly so; given its simply the result of DNA mutations run amuck, and there is so much DNA code vulnerable to mutations. Perhaps the next step would be to get more info on which cancers a ketogenic diet would help, and which it would hinder.


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