Leading Cancer Researcher Professor Thomas Seyfried Argues Cancer Is a Metabolic Disease, Not a Genetic One
Steven Bartlett interviews Professor Thomas Seyfried of Boston College, who argues that cancer originates in damaged mitochondria rather than DNA mutations.
Summary
Steven Bartlett interviews Professor Thomas Seyfried, a biologist at Boston College who has spent decades researching cancer as a mitochondrial metabolic disease. Seyfried argues that the mainstream oncology field's foundational belief — that cancer is caused by genetic mutations — is incorrect, and that cancer instead originates from damage to the mitochondria, the energy-producing organelles in every cell. He contends that this misunderstanding is causing 1,700 Americans to die from cancer every day, a figure he says worsens each year despite billions spent on research and treatment.
Seyfried presents a glucose ketone index (GKI) as a biomarker tool that individuals can use to monitor their metabolic health and reduce cancer risk, and describes a therapeutic strategy combining nutritional ketosis with low-dose chemotherapy that he says is keeping terminal cancer patients alive far longer than standard care. He also reveals an embargoed paper, soon to be published as a lead article in Frontiers in Science, which he describes as a comprehensive strategy to manage cancer effectively based on bioenergetic principles.
A central illustrative case is Pablo Kelly of Devon, England, a glioblastoma patient who declined radiation and chemotherapy and instead pursued metabolic therapy alone, surviving 10 years. His originally inoperable tumour became so well-demarcated that it was surgically debulked four times; he died from a cerebral haemorrhage during the final surgery, not from the tumour itself.
Seyfried also describes a press-pulse therapeutic strategy that pairs nutritional ketosis with repurposed drugs such as mebendazole, designed to simultaneously block both cancer's primary fuels — glucose through glycolysis and glutamine through glutaminolysis — in order to comprehensively suppress tumour growth without the toxicity of standard chemotherapy.
Key Takeaways
FULL TRANSCRIPT
The Embargoed Paper and the Core Claim
Steven Bartlett: You have an envelope in front of you there that says "confidential" on the front of it. What is in that envelope?
Professor Thomas Seyfried: It's a paper that's under embargo because the world thinks it's going to be very important. It's going to be a lead article in Frontiers in Science, because this is a strategy to manage cancer effectively, and we have a lot of evidence to keep these people alive a hell of a lot longer. We have given hope to the hopeless.
Steven Bartlett: And you have a perspective on treating cancer and other metabolic diseases that others don't have.
Professor Thomas Seyfried: Yes. But the problem is the field doesn't understand what I'm saying about the origin of cancer. So everything comes back to mitochondria, and all chronic diseases and cancer are the result of damage to this organelle. The science is telling us this, but the field of cancer has yet to accept it. That is a tragedy.
Steven Bartlett: Are you pissed off about this?
Professor Thomas Seyfried: Well, who wouldn't be? There are 1,700 people a day in this country dying from cancer. That's 70 an hour. And it gets worse every single year. When are people going to wake up?
Who Is Professor Thomas Seyfried?
Steven Bartlett: Professor Thomas Seyfried, what is it that you've committed your life to doing?
Professor Thomas Seyfried: We are committed to managing cancer effectively without toxicity, which is based on the science that I and others have done in this field.
Steven Bartlett: You have a perspective on treating cancer and other metabolic diseases that others don't have — the mainstream, should I say.
Professor Thomas Seyfried: Oh yeah. Mainstream doesn't have it for sure. But it's based on science. My work is based on what Otto Warburg, the famous German scientist, said from the 1920s, '30s, and '40s. He clearly showed that cancer was a mitochondrial metabolic disease.
Steven Bartlett: What does that mean — mitochondrial metabolic disease?
Professor Thomas Seyfried: It means that the origin of the disease resides in the organelle called the mitochondrion. It's in the cytoplasm of the cell. It used to be called — and still is — the powerhouse of the cell. It gives the cell its energy.
What the Mitochondria Actually Does
Steven Bartlett: I think we have a mitochondria model. Could one of my team bring one in?
Professor Thomas Seyfried: Well, you have a mitochondria in here. Oh, here we go.
Steven Bartlett: You've got one each here.
Professor Thomas Seyfried: Yeah. See, this is the little organelle. It looks like a bean shape, but it's actually a tubular network — these are tubes. And they respond dynamically inside the cell to both internal and external activities. You have to realise that at the time of conception, all of the mitochondria for the developing embryo are in the cytoplasm from the mother.
Steven Bartlett: The cytoplasm.
Professor Thomas Seyfried: The mitochondria are not in the nucleus. They're in the cytosol — outside of the nucleus, but in the cell body itself. All of the mitochondria determine our destiny. They will determine how long you will live on the planet, if you don't have an unfortunate accident or something like that. They have an expiration date. Different species die at different times. You don't find people living 400 years. Mice live about two and a half years. Elephants live as long as we do, or thereabouts. But that's all determined by this organelle. So you can see I have wrinkles — this is from living on the planet, from wear and tear on this organelle, which allows us to make energy efficiently.
So when this organelle starts to falter with age, you die from old age. This organelle has to be protected and respected if you would like to live a normal lifespan. But in the diets and lifestyles of today, we damage this organelle, and that damage can then present itself in various ways. It not only controls the internal environment of the cell — it also controls the neighbouring cells. The liver neighbourhood, the lung neighbourhood, the colon neighbourhood, the brain neighbourhood, the neuron neighbourhood. They all come from the same origin in that cytoplasm, and they determine the overall metabolic health of your body. They communicate with each other across cells and across tissues. This organelle controls a lot of what the nucleus does. It tells the cell when to divide. It tells the cell when to slow down.
Steven Bartlett: It's kind of like a brain, but also like an engine room.
Professor Thomas Seyfried: It's kind of like that. Certainly the brain part of it is really mysterious in the sense of how it controls the destiny of the cell in the body.
How Mitochondrial Damage Leads to Disease and Cancer
Steven Bartlett: So sickness, disease, cancer — what do we know about the role that this little thing plays in these chronic diseases and illnesses and cancers that so many people suffer with?
Professor Thomas Seyfried: This is the organelle that becomes damaged. And it can be damaged in many, many different ways. For cancer, which is what we have spent a lot of our time on — and now we've moved into the whole chronic disease issue, because each chronic disease can have different manifestations of ill health to the mitochondria in a particular population of cells — in the case of cancer, which we call the most serious of the chronic diseases, creating the most trauma, the most emotional distress, we have clearly shown based on many works that multiple things from our environment can damage this organelle in a particular population of cells in a particular organ.
For example, when you talk about carcinogens — a chemical that causes cancer — how does that chemical cause cancer? It damages the proteins and the lipids. These little squiggles are delicate internal membranes. They contain the proteins and the lipids that allow us to generate energy when we breathe. You're breathing, I'm breathing. I take in oxygen. Oxygen serves as a final acceptor for electrons that allows ATP to come out of this organelle — and don't forget, it's a tubular network.
Steven Bartlett: And ATP is the energy currency.
Professor Thomas Seyfried: It's the chemical energy currency. It allows enzymes to work, allows all the metabolic machinery inside a cell to work optimally.
Steven Bartlett: So just to play this back — oxygen comes in because I breathe in, I eat food, and in that mitochondria it does a process and spits out ATP as the energy.
Professor Thomas Seyfried: And the waste products of good energy metabolism would be CO2 and water. So when we burn gasoline in the engine of a car, we break down the octane, the carbon-hydrogen bonds, and we have an internal explosion that drives pistons. The exhaust is waste products from breaking down the fuel. We're doing the same thing inside the cell. We're combusting carbon-hydrogen bonds, and that combustion is a graded process — not an immediate explosion. You're breaking down the carbon-hydrogen bonds in a very precise way, producing ATP, which then drives the entire machinery of the neurons and the rest of the body.
It can respond dramatically to energetic stress, emotional stress. A carcinogen, for example, or intermittent hypoxia — like people who have sleep apnea, they stop breathing for 30 seconds or more — creates ROS, reactive oxygen species. These damage those delicate membranes. If it's too acute, too stressful, the whole cell will die — the cell loses its energy and we get apoptosis or necrosis, cell death. But if it's gradual and chronic, over months and years, this organelle loses its ability to produce sufficient energy. The cell compensates by using these ancient pathways — heirlooms of our evolutionary past.
All life on the planet evolved without oxygen, in the dark. These cells grew like crazy. There was no regulation. They were single cells with unbridled proliferation. They didn't have mitochondria. They had bacteria, and the bacteria — which this organelle came from — was a fusion between one cell that had a nucleus and was fermenting through the cytoplasm, and this bacteria, which became the mitochondria, came in. Now you have two different forms of energy: the energy in the cytoplasm, the ancient fermentation, and then this new form which can take in oxygen and generate energy much more efficiently.
One of our big discoveries — you see that space in the middle there?
Steven Bartlett: Yeah.
Professor Thomas Seyfried: That's called the matrix. That's where the Krebs cycle, the TCA cycle, breaks down the food that we eat. But they have an ancient part of a fermentation mechanism inside, because before oxygen came, all life forms were fermentors. They produced energy without oxygen because there was no oxygen. We had to wait for those bacteria to make oxygen through a photosynthetic process. But all organisms were fermentors in the beginning. After this organelle came in and was able to take in oxygen and make energy really efficiently, that ancient fermentation pathway remained in the matrix. So we have it in the cytoplasm of the cell, and this organelle — our big discovery, with the work of Christos Chinopoulos from Semmelweis University, who is the world leader on that little pathway — when this organelle becomes impaired, these ancient pathways of energy through fermentation arise. They try to replace the lost energy from oxidative phosphorylation.
Steven Bartlett: What does that mean?
Professor Thomas Seyfried: Energy through oxygen.
When the damage to oxidative phosphorylation is too acute, the cell will die. Cyanide is a perfect example. You take a mouse, a rat, or a person, and they drink cyanide-laced Kool-Aid — they die, because the cyanide binds to the protein that uses oxygen for energy and the whole system shuts down.
Steven Bartlett: Suffocates you basically.
Professor Thomas Seyfried: Yeah, you die instantly. For chronic diseases, it's usually not an acute stress on this organelle — it's a chronic stress. In cancer, what happens in a particular tissue, whether it's bone, lung, bladder, or brain, is that the cell gradually compensates with these ancient fermentation pathways. This organelle signals to the nucleus — mitochondrial stress response, retrograde signalling. The nucleus acts as a respondent to what this organelle wants. So the nucleus turns on oncogenes, which you've heard a lot about. They open the floodgates to bring in the glucose and glutamine that allow the cell to grow in a disregulated way. They go back to these ancient fermentation pathways where there was no regulation, because this organelle was not part of the regulatory system.
The Oncogenic Paradox
Steven Bartlett: What's the oncogenic paradox?
Professor Thomas Seyfried: That was the paradox first put out by Albert Szent-Györgyi, a Hungarian scientist who received a Nobel Prize for vitamin C. He said there's a paradox. We know multiple things in the environment can elicit cancer — we've identified oncogenic viruses, chronic inflammation, carcinogens, intermittent hypoxia, rare germline mutations. He said we don't understand the common pathophysiological mechanism by which any of those provocative agents would elicit disregulated cell growth, which is cancer.
When you talk about cancer, what do people say it is? It's cell division out of control. It's disregulated cell growth. This organelle determines when cells should divide and when they should not divide. It regulates the destiny of the cell. So what happens when this organelle becomes chronically impaired? It falls back on these ancient pathways that existed before oxygen came into the environment, where all the cells were disregulated in their growth because they didn't have this regulatory system — the mitochondria, coming from a bacterium.
Steven Bartlett: So let me play that back. In this mitochondria here, there is an ancient — because this came from a fusion of bacteria a long, long time ago — the old bacteria used to be very selfish and just think about itself. It used to grow on its own and didn't communicate with anybody. It had its own way of growing and multiplying that was really not in cohesion with anything else. That is still in there somewhere. And although now in its modern form, because there's been that fusion, it grows thinking about the wider organism — when it becomes damaged, it falls back on that old selfish way of growing. And that's kind of what can cause cancers.
Professor Thomas Seyfried: It's close, in the sense that we don't know about the "thinking" — we just know the consequences of what happens when it falls back on those ancient pathways.
Now, people knew from Otto Warburg that cancer is an energy problem in the cell. Why would the cells start to ferment and produce a massive amount of fermentation waste product, which is lactic acid, even in the presence of 100% oxygen? They're still fermenting. Why? That shouldn't happen.
When people have heart attacks, they stop breathing, the heart seizes, and the bloodstream immediately fills with fermentation waste products — lactic acid and succinic acid. If you don't start breathing in a short period of time, you're going to be dead, because the neurons in your brain cannot sustain fermentation energy for very long. As soon as you give cardiac massage and the heart starts beating again, the lactic acid and succinic acid go away. They disappear, because you're breathing now. You don't need to ferment when you have oxygen in the environment.
Cancer cells — Warburg said it's the weirdest thing — continue to ferment even in 100% oxygen. Why are they doing that? He speculated that this organelle was irreversibly damaged. He didn't have an electron microscope at the time. He didn't have the sophisticated tools that we have today. So he projected it all onto biochemistry. He was a biochemist, and he said you should not produce fermentation if you have oxygen — oxygen should shut that off and these cells should return to normal metabolic homeostasis. He said that's because there's something irreversibly damaged in this organelle.
A lot of people attacked him and said, "We don't have any evidence for that." Some cancer cells continue to take in oxygen and make ATP — therefore Warburg must be wrong. We showed that the cancer cell takes in oxygen, but it's not making energy through ATP in any great amount. It's using oxygen for ROS — reactive radicals that further damage and cause the DNA mutations that everybody is chasing. It's all downstream effects of damage.
What This Means in Simple Terms
Steven Bartlett: So what does this mean in simple terms?
Professor Thomas Seyfried: It means we have disregulated cell growth. That's ultimately the problem we're dealing with. We can't control how these cells are dividing. We're throwing all kinds of crazy stuff at them — trying to poison or radiate or surgically remove them. We're trying to do everything to stop this disregulated cell growth.
So when we look at this organelle under the electron microscope, we find the cristae are often missing. You have what they call ghost mitochondria — you've got the shell but nothing inside, or if there's something inside, it's all deformed. We know there's a foundational principle in biology: structure determines function. If the structure is abnormal, the function will be abnormal. This is known to all biologists except oncologists. They don't seem to understand it.
Steven Bartlett: What's an oncologist?
Professor Thomas Seyfried: Those are the people who study cancer.
Steven Bartlett: So what are you then?
Professor Thomas Seyfried: I'm a biologist. When we know that if the organelle is damaged, you're not going to be able to produce energy efficiently by oxidative phosphorylation.
Steven Bartlett: I think you're a bit further down the road, Thomas, than a lot of my viewers are. For me, hearing that there's this energy engine in my cells — and there are trillions of them — and they also communicate with each other, and when this becomes stressed or hurt or damaged because of lifestyle choices, energy production and efficiency will change, and that could cause this to die or malfunction in some way — for me, I go, I've got it.
Professor Thomas Seyfried: Okay, that's a major step forward. Now we build upon that. So here's the situation. We've discussed that cancer cells — all of them that we have ever looked at — have defects in the number, structure, and function of that organelle. I published a big paper where I spent over a year going through the early electron microscopy literature. Warburg didn't have that opportunity because that technology was not there for him. So he speculated based on the biochemistry. But I went back and looked at these electron micrographs of mitochondria in various cancers, and they're all damaged. There are few of them where the cristae are intact. I work with some of the best — like Aris Mardinly, who is a world leader in beautiful electron microscopy of cancer cells — and you can see all the damage under his magnificently beautiful work.
And let me tell you something else, Steven. In the cytoplasm, these organelles are also in contact with other cellular membranes, like the endoplasmic reticulum. There are intimate contacts between some of the other membranes — mitochondria-associated membranes — and they're also abnormal when you look at them under the electron microscope.
Steven Bartlett: The ones it's talking to are abnormal.
Professor Thomas Seyfried: Yeah. The mitochondria are abnormal and the membranes that contact them are abnormal. And that intimate contact — I'll get into the calcium signalling a little bit later, which controls the destiny of the cell. Why is the cell growing out of control? Well, first of all, it's fermenting. That means it's getting energy from sources other than oxidative phosphorylation. You can take a cancer cell and treat it with cyanide or in the absence of oxygen and it's still living, still growing, because it's not using the oxygen pathway. They're falling back on oxygen-independent mechanisms, which are called fermentation.
Steven Bartlett: So I understand that to be that there's a malfunction in the mitochondria, which means it no longer uses its oxygen pathway as sufficiently as it should — there's always some residual level — and it finds another way to make energy, which is how it survives.
Professor Thomas Seyfried: Yes.
Steven Bartlett: And then it stops communicating with the rest of the cell.
Professor Thomas Seyfried: Well, it actually communicates with the nucleus to open up the floodgates to bring in the fuels that drive this fermentation energy. It gets more and more greedy. It has to, because you're taking an organelle that produces energy highly efficiently — like 34 to 36 ATPs with oxygen — and now you're trying to replace that with fuels that give you two moles of energy. So it's very inefficient. You have to take in a tremendous supply of the fuels that will give you energy.
Steven Bartlett: Which are?
Professor Thomas Seyfried: Glucose — the sugar — and the amino acid glutamine. Our bodies are loaded with glutamine. It's the most abundant amino acid in our bloodstream. Evolution provided that for us because if we stop breathing, we use that fuel to keep the cells alive. Our gut is controlled by glutamine. Our immune system uses glutamine.
Steven Bartlett: What is glutamine?
Professor Thomas Seyfried: It's an amino acid, which we can make from food. They call amino acids essential and non-essential. Essentials are ones we must eat — we must have certain foods that provide these. Glutamine is considered a non-essential amino acid because we can make it from sugar. But it's the most abundant amino acid in our body.
Why Modern Populations Have More Cancer
Steven Bartlett: What are the lifestyle factors that are drastically increasing the probability of this happening?
Professor Thomas Seyfried: It's not necessarily what the person did in all cases — it's what the person was exposed to that could have elicited this. That's the oncogenic paradox. We have shown that inflammation produces cytokines. When you have chronic inflammation, they damage the ability of this organelle to make energy efficiently. Chronic inflammation is known to be a risk factor for cancer. Chronic inflammation, intermittent hypoxia, carcinogens.
Steven Bartlett: What's intermittent hypoxia?
Professor Thomas Seyfried: It's like sleep apnea. Warburg had clearly shown that intermittent hypoxia on cells would damage the efficiency of oxidative phosphorylation, leading to compensatory fermentation.
When we look at the populations around the world that have the most prevalence of cancer, it doesn't appear to be countries like Niger, Gambia, or Nepal — they consistently rank at the very bottom for cancer incidence. Conversely, high-income countries like Australia, New Zealand, and the United States have the highest rates of cancer. Why is that?
It's because of our technology. We are still palaeolithic man, and our biology has allowed us to store energy efficiently because of times of famine. We are now in a new environment where we have massive amounts of highly processed carbohydrates, inactivity, emotional stress, poor sleep habits. You pile all those together with exposure to carcinogens, and you chronically damage this organelle. In some organs — if it's the breast, if it's the lung, if it's whatever — that organelle becomes chronically damaged in some population of cells in a particular organ, and you can elicit disregulated cell growth as a result.
You know what I find interesting? If you can keep your mitochondria healthy — because palaeolithic man, our ancestors from 500,000 years ago, or modern people living in these countries according to traditional ways with minimal interference from modern diet and lifestyle — have lower amounts of cancer in general. This is what Albert Schweitzer found. He was specifically looking for cancer in African tribes and said remarkably it's extremely low. What are these people doing where western society has a lot of cancer and these Africans living according to traditional ways do not?
They have a lot of exercise. They're eating all organic foods. They're not under the same kind of stress or exposure to chemicals that modern societies have. And you find very low cancer.
For example, dogs all evolved from the wolf. Wolves in the wild rarely have cancer. The domestic dog — cancer is the number one killer of the domestic dog. What is the dog doing that the wolf isn't? The wolf is out running around eating natural foods. The dog is in an apartment somewhere, gets a dog walker once a day, and the next thing the dog is obese and full of cancer.
So it all comes down to what you do to maintain the health and vitality of the mitochondria. That reduces the risk of damaging them chronically. That can explain in large part why modern societies are struggling with chronic diseases — not only cancer. We have type 2 diabetes, obesity, high blood pressure, even neuropsychiatric problems. If you can protect and keep this organelle healthy, you reduce risk.
Now, people say cancer has to be genetic because we have inherited genes that put us at higher risk, like BRCA1 for breast cancer and Li-Fraumeni for a variety of other cancers. Our paper — done by Bob Kaplan — went through and looked at all the genetic risk. None of these mutations are 100% penetrant, meaning they're secondary risk factors. A primary risk factor would be that every time that mutation is there, 100% of the people get the disease. I work in Tay-Sachs disease, in inborn errors of metabolism — those mutations are 100% responsible for that condition. There's no gene mutation that's 100% penetrant for cancer. Most of them are what they call incompletely penetrant.
So what does that tell us about the nature of the disease? Bob went back and looked at what every one of those gene mutations does — in some way, each one disturbs the efficiency of oxidative phosphorylation in that organelle. We have all the evidence. All the risk factors, all the genetic ones — all of them damage the efficiency of energy through this organelle.
So that's like carcinogens, like viral infections. The viruses like hepatoma and papilloma — their products will go in and damage it, or they will replicate inside this organelle, screwing up the efficiency, causing compensatory fermentation, causing disregulated cell growth through abnormal calcium signalling, causing cells to no longer be responsive to their neighbours.
The Glucose Ketone Index
Steven Bartlett: Give me a prescription of how I should live my life to keep my mitochondria healthy.
Professor Thomas Seyfried: Well, that's why we developed the glucose ketone index calculator — the first biomarker tool that can allow people to know the level of health of their mitochondria. Because when you shift from carbohydrate fuel to lipid fuel —
Steven Bartlett: What's lipid fuel?
Professor Thomas Seyfried: Fat. Ketones are a water-soluble breakdown product of fatty acids. We store fat in adipose tissue — we have fat all over. That was there because as a species we had to survive in the most harsh environments. Food was not always there. We had to survive all kinds of famine, all kinds of absence of food. Our bodies are machines that were honed over millions of years to be super efficient. Glucose is gold — sugar. You either burn it or you can store it as fat. But when you're not bringing in sugar, that stored fat moves into the bloodstream, goes to the liver, and it's like taking a branch and putting it in a chipper — out come these little soluble ketone bodies. They're breakdown products of long-chain fatty acids. They can replace sugar for the brain, for the muscles, for most other cells in the body. They can replace the energy of glucose.
So we evolved that way. But we're now in an environment where we have massive amounts of highly processed carbohydrates, and we don't want to pee them out unless you have diabetes. So we store them as fat. We have an obesity epidemic as the result of our evolutionary ability to store energy — which kept us alive as a species, because if we were unable to store fat 500,000 years ago, we would have all been extinct.
When we lose that ability to manage energy efficiently — when we have so much energy in the environment, stress, no exercise, all of this — we store more and more fat and produce an environment that's very damaging to this organelle.
Steven Bartlett: Say that again. How does stress impact that?
Professor Thomas Seyfried: Stress elevates corticosteroids. When you're under stress — you get into a fight, an argument, or you're stressed out by a business deal going bad — corticosteroids elevate blood sugar, contributing to systemic inflammation. It's okay for a short period of time to be pissed off at something. But it's the chronic stress — the chronic doom scrolling, all this crazy stuff while eating highly processed food and not moving — all of this creates stress on this organelle in some population of cells. It damages the efficiency of this organelle to produce energy effectively, and that either will kill the cell gradually if it can't use compensatory fermentation, or predispose you to cancer.
So either way is unhealthy. We have chronic disease. Cancer is the number one big dog in the chronic disease world. It's the one that people fear the most. Type 2 diabetes, cardiovascular disease, dementia — all of these are part of damage to this organelle in one way or another. For Parkinson's disease, when that organelle gets damaged, the cells of the substantia nigra die. They are incapable of compensating with fermentation, so they die. Cancer is very rare in neurons of the brain — neurons can't compensate with fermentation, so they die. So you either get compensatory ancient fermentation leading to disregulated cell growth, which we call cancer, or you get cell death leading to chronic diseases.
Steven Bartlett: What about sleep? What's going on with sleep that's causing issues?
Professor Thomas Seyfried: Sleep is a way we can restore the energy efficiency of the mitochondria, if we're well slept. Everybody feels good when you have a good night's sleep. Your body feels rejuvenated because you're not stressing out. You're reducing the burden on this organelle to manage the metabolic environment. If you're up all night, stressed out, never giving this organelle a break in a particular cell in a particular part of an organ, you can get neuropsychiatric problems, digestive problems, cancer, type 2 diabetes — we put it all in the paper, all the different things that can chronically or acutely damage oxidative phosphorylation.
So sleep basically gives the mitochondria a little bit of a break.
Steven Bartlett: Yes. It gives your whole body a break, let's be honest. But you pile those things on together — lack of exercise. Our ancestors, how hard is it to run down and kill a big buffalo or a woolly mammoth? You're exhausted after doing something like that. As a matter of fact, you chase these animals, you separate them. This is another thing that was really interesting — it came out of Israel, I think it was last year. They looked at what cavemen were eating. They were eating the strongest members of the herd, leading to the indirect extinction of these animals. They found that if you eat the strongest member of the herd, you get the vitality of that organism, because they knew the marrow and the physiology of that animal at that point in its life could provide you with the strength it had. But when you eat the strongest members of the herd, you leave the old and the young vulnerable to predators, leading to extinction. A big paper came out of Israel looking at what these cavemen were eating like 500,000 years ago. Humans indirectly caused the extinction of other species in part because they were eating the toughest members of the herd.
These guys were chiselled. They weren't dying from type 2 diabetes, cancer, or dementia. They were dying from infections, injuries, and child mortality. When you bring your body back into a low glucose-ketone state, you're actually going back to how you were. This is why we developed the glucose ketone index.
The Story Behind the GKI
Steven Bartlett: What is in that envelope in front of you?
Professor Thomas Seyfried: It's a paper that's under embargo because the world thinks it's going to be very important. It is. It's a way to keep that organelle healthy — a way to manage energy efficiency in the body.
Steven Bartlett: And this hasn't been released yet.
Professor Thomas Seyfried: It hasn't been released. It's coming out. It's going to be a lead article in Frontiers in Science. And not only that — the paper was written for scientists, and then the journal decided to make a second copy for what they call "young minds," so letting kids aged 8 to 14 synthesise it down. One of my colleagues said that's probably what most people will be reading, because they don't want to know about the bioenergetics that actually goes on inside this organelle to explain why this chart means something.
Steven Bartlett: And you've been working on this for some time.
Professor Thomas Seyfried: I built the GKI. Let me tell you the story. There was an American woman, a lawyer — Trudy Dupont — who developed a kind of brain stem tumour. After I wrote my book, Trudy wanted to use this metabolic therapy. She stayed alive much longer — over 10 years. We kept her going. She eventually passed away, unfortunately. So I was measuring — because we knew that the tumour cells needed sugar to grow, as Warburg showed, and many other people showed — and they can't burn ketones, because you need a very efficient mitochondria to burn ketones for energy. Our normal cells can burn ketones for energy, and that gives us tremendous efficiency. We can actually breathe lower oxygen and make more energy if we can burn ketones efficiently in this organelle. But if the organelle is damaged, they can't use the ketones. They can't burn fatty acids or ketone bodies.
Stephen, you can't believe how people misinterpret information. They see droplets of fatty acids in the cytoplasm and say, "You see, the cancer cell needs all that fatty acid." No — they can't use it. It's there to protect them. If they try to burn it, they blow this up and die. So there is a storage of fat, but they can't burn fatty acids or ketone bodies.
So I knew cancer needed glucose, and I knew cancer couldn't burn fatty acids or ketones because this organelle is broken. So I'm measuring glucose and ketones independently in Trudy. She's doing the finger prick thing, sending me the information back — "Here's my glucose, here's my ketones."
Steven Bartlett: Okay, so I have a ketone glucose reader in front of me. If I put my blood on this strip, it tells me my glucose levels. If I put my blood on this strip, it tells me my ketone levels.
Professor Thomas Seyfried: Right. But if you look at them independently, glucose is very volatile, very variable. And this is why I developed the glucose ketone ratio. Trudy had a parking spot for handicapped people because she had a cane — her brain stem glioma was preventing her from walking effectively. Somebody took her parking spot. She was furious. So she ran upstairs and took her blood sugar and it was 186 milligrams per decilitre — very, very high. She was on a ketogenic diet, and she emails me and says, "I'm going to die. My cancer is going to grow fast. What's going on? My blood sugar is like 186, and you told me it was supposed to be 60 or 65 or in that zone." I said, "What's your ketone level?" "Oh, it's still like 0.9 millimolar." I said, "Well, that didn't change, right?" "No, just the sugar changed."
So I said to the students working with Josh Fidenbauer, "Trying to measure these two independently is very hard to figure out." So what we decided to do — because glucose comes out in milligrams per decilitre whereas ketones come out in millimolar — we had to convert glucose to millimolar and divide it by the ketone in millimolar. Then you get a number that's not all over the place. It's very stable. So because of Trudy, that one cancer patient, we developed the ratio. Then later on we realised that this ratio is a statement of how healthy your mitochondria actually are.
When you have a low ratio, you're in palaeolithic man territory. You're back in the zone where we didn't have chronic diseases, because we didn't have damage to the organelle that would cause those diseases. Palaeolithic man was always in some sort of state of ketosis because they wouldn't have food for periods. They were very active. They didn't have chronic diseases, but they had other kinds of diseases.
Then my student Derek Lee, myself, and Christos Chinopoulos started to make a ratio chart. These are the numbers you get when you divide your sugar by your ketones.
Testing the GKI Live
Steven Bartlett: Okay, so my sugar divided by my ketones. So if I did my glucose measure now on this little device —
Professor Thomas Seyfried: Let's see what your GKI is. You had a ketone of 0.4 millimolar. What was your sugar?
Steven Bartlett: 90.
Professor Thomas Seyfried: Okay. So you have to divide. You have to convert. You divide 90 by 18 and you get a number.
Steven Bartlett: Five.
Professor Thomas Seyfried: Five. So divide five by 0.4.
Steven Bartlett: 12.5.
Professor Thomas Seyfried: Okay. So here you are — 12.5. You're down here in the prevention zone. This is where palaeolithic man mostly lived. Palaeolithic man lived in the yellow-green zones because they didn't have access to all the things that would drive up blood sugar. When your blood sugar goes through the roof, your ketones are really low because insulin is now driving it down. So that's good.
Steven Bartlett: I did the carnivore diet for a week — eating big ribeyes, bacon and eggs, lamb. I did it for a week and I was able to get down to 10.
Professor Thomas Seyfried: Okay. And you could get lower, but you were loving the ribeye so much you ate a little too much of it. You have to have some level of discipline.
So this is what we call the zone of prevention. It's very hard to get cancer or chronic diseases when you're in these zones, because you're keeping this organelle quite healthy. When you live in these zones consistently — and you don't have to live there consistently, because humans evolved as a scavenger species. We would engorge ourselves because we knew it wasn't happening every day. Modern man is living in the feast every single day. And that's why we have all the chronic diseases.
This red zone is the zone of risk for chronic diseases and cancer. When you look at the obesity epidemic, these people are living in the red zone. We can visit the red zone. We don't want to live in the red zone.
Steven Bartlett: So if I was to visit the red zone, it would look like eating high carbohydrate diets, lots of sugar.
Professor Thomas Seyfried: Yeah. No exercise. Eating five meals a day, snacking all the time. You can get GKIs of 500. You have people with blood sugars of 400 or 500 milligrams per decilitre and zero ketones. You do the math — it's unbelievable.
Steven Bartlett: You're basically saying I want to keep my blood glucose levels low and my ketone levels somewhat high.
Professor Thomas Seyfried: Well, you don't want to go too high, because people — physicians listening — will go, "Oh, he's going to go with ketoacidosis." Ketoacidosis is when you have ketone levels of 15 to 20 millimolar. What is yours? 0.4. That's called nutritional ketosis. That's how we evolved. When you have type 1 diabetes where you can't control insulin, you're going to get high levels of both sugar and ketones. That's a pathological condition. Most of type 2 diabetes — these are all pathologies based on damaging oxidative phosphorylation.
So what this chart does, for the first time — and we put it together because we did all the bioenergetics work — is show that if you can get into the green zones where your blood sugar is low and your ketones are elevated, you hammer the hell out of these tumour cells, because you're taking away one of their two primary fuels driving disregulated cell growth. And as the ketones go up, the rest of your cells in the body are getting super healthy. The tumour cells can't tap into the value of a ketone because the organelle needed in the tumour cell to do that is corrupted structurally and functionally. So ketones will make your normal cells healthy, but cannot be used to help the cancer cell because you need a good structural and functional organelle to burn them. So they become marginalised, and if the ketones go up, they're actually toxic to that cell to some extent.
But the cancer cells are now incapacitated — they're still there. You get rid of the abnormal inflammation, you get rid of the angiogenesis, the abnormal blood vessels. You're taking an angry tumour and making it much less angry, much less inflamed, more indolent. But it's still there. It's not gone, because the other fuel keeping this cancer cell going is glutamine.
Targeting Glutamine and the Press-Pulse Strategy
Professor Thomas Seyfried: So now when you have the patient in this green zone — this is for management. Prevention is never having to deal with what I'm talking about. If you're living in the yellow zone, the probability of getting cancer or chronic diseases is already reduced. But now you have some poor person out there who's been living in the red zone their whole life. They have to get down into the green zone and try to stay there as long as they can. But the cancer will still grow because it has access to glutamine. Glutamine is always in the bloodstream. You always have a surfeit of glutamine. So you have to come in now with drugs — repurposed drugs — to target the glutaminolysis.
I've looked at one, and that's mebendazole. People knew that mebendazole had some therapeutic benefit against cancer, but they didn't believe it until you show the mechanism. That paper shows the mechanism. It targets glucose and glutamine — the two fuels driving the disregulated growth of the tumour.
So here's the mitochondria. It's getting glucose from the cytoplasm and fermenting it, and also the amino acid glutamine comes in. You have to block the glycolysis and these two pathways. You have to restrict availability of glucose and glutamine together at the same time.
I speak only about things that I have tested in my lab and published papers on. The cancer field doesn't understand that the cancer can't grow without glucose and glutamine and can't switch to fatty acids or ketone bodies.
Steven Bartlett: That's still not going to kill the cancer though, is it? It's just going to —
Professor Thomas Seyfried: Yeah, we don't ever use the term "cure." But some of these tumours — let me tell you. We have people like Pablo Kelly from Devon, England. He had glioblastoma. He didn't take any radiation or chemo. He just did metabolic therapy. He lived for 10 years. He was diagnosed with an inoperable glioblastoma. They wanted to irradiate and poison him with drugs. He said no. He was one of these naturalistic kind of guys. He lived for 10 years and the tumour became operable. He had four debulking surgeries on an originally described inoperable cancer — cut out four times — because once we put the metabolic therapy in, the demarcation of the tumour became so clear that a neurosurgeon said, "I think I can get this out." But he never got rid of it entirely. He lived with it for 10 years, had a couple of kids. He died from a cerebral haemorrhage on the last debulking surgery. He never died from the tumour.
Combining Metabolic Therapy with Chemotherapy
Steven Bartlett: You're saying that the two work together in tandem. You're saying that the chemotherapy works in —
Professor Thomas Seyfried: So if you put the patient in nutritional ketosis, the ketogenic state facilitates the delivery of drugs to the tumour cell. It actually means you can use lower doses of drugs and get a bigger effect. The therapeutic benefit increases with lower dosing.
Steven Bartlett: So you want to be in ketosis when you do chemotherapy, radiation therapy.
Professor Thomas Seyfried: Yeah. And then you use much lower doses. This is what we're doing in Istanbul. We're taking pancreatic cancers — these patients are living four and five years. And advanced breast cancer and all these terminal cancers. We put them into some level of ketosis and then come in with the standard drugs — cisplatin, carboplatin, whatever — but you cut the dosages down big time, and then they have tremendous benefit. The title of the paper is "Ketogenic Diet as a Metabolic Vehicle for Enhancing Therapeutic Efficacy."
The current body of research suggests that being in a state of ketosis can act as a helper therapy, enhancing the cancer-killing effects of chemotherapy while simultaneously protecting healthy cells. Progressive oncologists are currently using ketogenic diets alongside standard chemo to maximise its efficacy. That's what we're doing in Istanbul and also in Greece.
Steven Bartlett: When you enter a fasted or ketogenic state, your healthy cells essentially go into bunker mode. They slow their division, conserve energy, and build up their defences. Cancer cells, however, do not have this evolutionary off switch. They continue trying to rapidly divide. When the toxic chemotherapy hits, your shielded healthy cells survive it much better, while the exposed, rapidly dividing cancer cells take the full hit.
Professor Thomas Seyfried: Yeah. In other words, you make the tools you have work better. The problem in the field of cancer today is they're not using the tools in the correct way.
Now, let me give you another example. If you take immunotherapies — chimeric antigen receptor T-cells, PD-1/PD-L1 inhibitors, they're called precision medicines — they're designed to attack a molecule on the surface or stop that cell from being resistant. Often times, they come at you after you've failed chemo and radiation, and then they come at you with an immunotherapy. The metabolic pressure shrinks down your tumour, makes it very indolent, non-aggressive, and the rest of your body is healthy. You're not going bald. You're not bleeding from your gums. Your microbiome isn't blown to hell. And then you can come in with low-dose chemo and immunotherapy, because whatever is left in that remaining residual mass, they may all have something in common for having survived all this. So now you can come in with a precision medicine and possibly achieve resolution.
Chemotherapy creates massive oxidative stress — damage inside the tumour. To repair the damage and survive, the cancer cell requires massive amounts of glucose. So if the patient is in ketosis, the tumour's glucose supply is essentially cut off. The cancer cell can't repair the DNA damage caused by the chemo, leading to faster tumour death.
Professor Thomas Seyfried: And there's another thing people overlook. What protects the tumour cell from chemo and radiation is the waste products of fermentation — the lactic acid and the succinic acid that are dumped out of this raging beast prevent these other therapies from working. So if you want your therapy to work, you've got to target those two fuels together at the same time. When you do that, this cell's shield is off. These things are super vulnerable to even low doses of chemo and radiation. And the immunotherapies — look, if you have an immunotherapy and you try to attack the beast when it's at its strongest, you're not going to win. And this is what happens — you get only partial response.
In the field of cancer today, they think living an extra six months is a major breakthrough. We're talking about living an extra five and six years. This is what's really important.
Why Mainstream Oncology Doesn't Recommend Ketogenic Diets
Steven Bartlett: I was reading some research to figure out if oncologists — cancer doctors — are currently recommending the ketogenic diet. It says the vast majority of mainstream oncologists do not recommend the ketogenic diet to their newly diagnosed patients. In fact, if a patient brings it up, many doctors will actively advise against it. The reasons for that — number one is the fear of cachexia. Cachexia is a severe wasting syndrome where patients rapidly lose muscle and fat. It is a massive problem and a leading cause of mortality in cancer patients. Because the ketogenic diet suppresses appetite and often leads to weight loss, oncologists are terrified that a strict keto diet will accelerate cachexia and weaken the patient.
Professor Thomas Seyfried: Well, that's because they have not heard what I just said with respect to the biology and biochemistry. Cachexia — there are two ways you can lose weight in cancer patients. Cachexia is the ability of the tumour cell to mobilise energy out of the muscles. It's taking the glutamine out of your muscles and feeding the tumour. This is one of the two fuels driving the beast — glutamine. Where are they getting the glutamine from? Not only from the bloodstream, but they dissolve your muscles as part of that process. So when you put a patient in nutritional ketosis, the weight loss is therapeutic weight loss. Cachexia is pathological weight loss.
Steven Bartlett: I also just wanted to pick up on the point we were talking about earlier, which is about the metabolic approach to cancers. It says here — and this goes to the point about people telling you to just eat whatever you want while you're managing cancer — because the primary goal of the hospital dietitian is to prevent weight loss during brutal chemotherapy regimes, patients are frequently told to eat whatever they can keep down. It is incredibly common for cancer patients to be handed meal replacement shakes which are often packed with corn syrups and refined sugars, ice cream, and high carbohydrate comfort foods just to keep their caloric intake up. From a metabolic perspective, this is a tragedy. While it keeps weight on the patient, it simultaneously floods the bloodstream with glucose and insulin, directly feeding the tumour.
And while keto is not the standard of care, the landscape is beginning to slowly shift. There is a growing minority of integrative oncologists and specialised metabolic clinicians worldwide that actively prescribe therapeutic ketosis alongside conventional treatments. Those doctors use the keto diet and fasting protocols to protect healthy cells and sanitise tumours before administering lower, more targeted doses of chemo.
Professor Thomas Seyfried: That's what we developed. That's our plan. That's what we're doing. We do that because we understand the biology and biochemistry. And that's why we're developing the new society called the MORE Alliance — Metabolic Oncology Research and Education. This is bringing together what you just mentioned in a logical approach to manage cancer. This is a logical approach based on the hard science of decades of research, initiated originally by Otto Warburg and then continued by our group at Boston College.
The Somatic Mutation Theory vs. the Mitochondrial Theory
Steven Bartlett: Some of the background context here is that mainstream oncology operates on the somatic mutation theory — the belief that cancer is fundamentally a genetic disease driven by DNA mutations. Because their training focuses on genetics, their treatments are designed to target DNA and cell division, like radiation and targeted genetic therapies, rather than manipulating cellular metabolism. And mainstream medicine requires massive multicentre double-blind phase 3 clinical trials before a protocol becomes the standard of care. Dietary interventions rarely get the level of funding. So oncologists lack the institutional green light to prescribe them to patients and tend to say, "Eat what you can."
Professor Thomas Seyfried: I don't blame them. Many of them are good people. The problem is the system doesn't train them to understand the biology and biochemistry of the disease they're treating. Some of them become very resistant to this. They get angry because they think, "Why wasn't I told this?" Well, first of all, they're not reading these papers. You ask them about it and they say they've never read it. Well, how are you going to know anything if you don't read the literature?
Listen to this. The National Cancer Institute, on their website, says cancer is a genetic disease — caused by what you just described. I said, "Why don't they put the articles in there showing all the tumours where they can't find any mutations?" The somatic mutation theory says that cancer is caused by random genetic mutations. New sequencing of normal people like you and me is finding mutations in all these driver genes in cells in our body that aren't in disregulated cell growth. So we're calling them wild-type cancers.
Steven Bartlett: You lost me.
Professor Thomas Seyfried: Okay. The nucleus of a tumour cell — a raging tumour cell. What's causing that cell to grow? Is it the mitochondria in the cytoplasm, or is it the mutations in the nucleus? According to the somatic mutation theory, it's the mutations in the nucleus that are causing the disregulated cell growth. You take that nucleus and put it into an enucleated normal cell.
Steven Bartlett: And there's no cancer.
Professor Thomas Seyfried: No cancer, no disregulation. There must be something else. Then you take the nucleus of the normal cell and put it into the cytoplasm of a tumour cell, and you get disregulated cell growth.
Steven Bartlett: So it must be something other than the nucleus.
Professor Thomas Seyfried: Yes. The mitochondria.
With mitochondria controlling our destiny, and the field of cancer having yet to understand it, accept it, and say, "Well, we can't do any of this until we do a double-blind crossover" — what do you mean? The science is telling us this. That's your way of protecting a broken system.
Steven Bartlett: Are you pissed off about this? Because you do seem pissed off about this.
Professor Thomas Seyfried: Well, who wouldn't be, Steven? There are 1,700 people a day in this country dying from cancer. That comes out to 70 an hour. And it gets worse every single year. The American Cancer Society says that this year, in 2026, we will have 626,000 souls leave the planet from cancer. And every year it gets worse. So when you hear all the breakthroughs — we have television ads in Boston for cancer, breakthrough after breakthrough after breakthrough — all we do is get more dead cancer patients. Raise money for cancer. Where's the accountability for all the money you're raising? When are people going to wake up? You don't make someone healthy by irradiating and poisoning them. You've got to understand the biology and the biochemistry of the disease.
I have the concepts and the proofs, but the physician who works with the patient on a clinical basis — they're the ones who must apply this to the clinic. There's the hard science that's the bedrock, and then there's the clinical person who has the practice. Together, you get great success — better than anything that's out there today.
The American Cancer Society recently released its latest projections for 2025 and 2026. New cases — the ACS projects over 2.11 million new cancer diagnoses in 2026. That translates roughly to 5,800 new cases every single day. Approximately 626,000 Americans are expected to die from cancer in 2026 — about 1,700 deaths per day. Lung cancer remains the leading cause of cancer death, projected to cause more fatalities than colorectal and pancreatic cancers combined.
There has been no major advance in managing glioblastoma in 100 years.
Steven Bartlett: What's glioblastoma?
Professor Thomas Seyfried: That's the deadly brain cancer. It killed Teddy Kennedy from Massachusetts, Senator John McCain, President Biden's son Bo Biden. It's killed a lot of various people and it's considered a death sentence. But we're keeping these people alive. We're not saying we cure the cancer, but we can certainly keep them alive a lot longer. Pancreatic cancer — always considered so bad. We're getting very excellent results in managing pancreatic cancer using metabolic therapies. We know what to do and we know how to do it. I have clinicians and dieticians that work with me who know how to manage cancer effectively. We can do it right now, today. If someone were to say, "Seyfried, get your group together, let me see what you can do" — I will put up our metabolic therapy against any trial from any of these pharmaceutical companies. We can keep these people alive a hell of a lot longer.
If You Were President: A Policy Manifesto
Steven Bartlett: If you were made president today, Thomas — of the United States — and your primary objective is to bring down the 1,700 Americans dying from cancer a day — you can put in place policies to stop this happening and to also help people manage it better. What do you do?
Professor Thomas Seyfried: First of all, we wouldn't throw out everything. We have a strategy now to manage cancer effectively. We're not going to get rid of the drugs that are making billions and billions of dollars. We're just going to use them at lower dosages in a different way. But we also want to prevent it in the first place. Preventing it comes back to our chart.
Steven Bartlett: So what do we do to prevent these 70 people an hour dying of cancer?
Professor Thomas Seyfried: It's going to be education. Education number one. You have to let people know. And let me tell you something that's really important. It should not be any government or government official telling anyone what they should or should not eat. The power of this chart is personal. You're empowering the patient. They have to know. We're not going to tell somebody, "If you continue to eat bad food, you're at high risk," and that person says, "I don't care, I'll smoke cigarettes." The government's not going to come into this person's house and take away the bad food. No. Those foods are there because they give us pleasure, but the knowledgeable person would say, "I'd like to have it every now and then, but I can't live in that environment."
And the other thing we do terribly in this country — the poor people in these food deserts where you only get poor quality food. To go to Whole Foods where they have the expensive ribeyes and all this stuff — a lot of people can't afford the kinds of foods that will put them in these better healthy zones.
Steven Bartlett: So we're going to make healthy food more cost-effective and cheaper. Those are easy words to say, but in practicality it's not.
Professor Thomas Seyfried: Now, what kinds of foods should people be eating? I think they should just try to avoid the highly processed carbs. And exercise. There are a lot of things we can do that would mitigate the inflammatory conditions shown on this chart. The goal here is we know what keeps us healthy — it's the efficiency of that organelle. We want to do everything possible to keep that organelle healthy. We will reduce dementia. We will reduce diabetes. We will reduce obesity.
And people say, "Well, what about GLP-1?" Human beings want a quick fix for everything. We don't know yet where a GLP-1 would put you on the chart. We do know one thing — it lowers blood sugar. But how high a level would it bring ketones to? Because it's the ketones that keep the organelle healthy. So I'm lowering blood sugar, but am I raising the ketones that enhance the bioenergetic efficiency of the organelle? I don't know — it hasn't been done yet. I haven't seen any papers coming out on that.
Steven Bartlett: Okay. So you're saying exercise number three. I've got education, kill the food deserts so people can get healthy food, exercise —
Professor Thomas Seyfried: Reduce emotional stress. There are a lot of ways — music therapy, meditation, friends, happiness — all of those reduce stress. I had a guy from Japan or Korea at a big meeting one time. He said, "You want to get cancer? If your goal in life is to get cancer, you've got to eat crap food all the time, have terrible sleep, make sure you never leave the couch, sit in front of the TV all day, doom scroll, never exercise, and make sure you don't have any friends or be happy. You're on a fast track for not only cancer, but all these other chronic diseases." So what I just said is — you need to not do that.
There are not many people who are going to be measuring their GKI every day, but there are people who love to measure that kind of stuff. And they're making continuous glucose-ketone monitors now. Apps are coming out. I have my students making these apps in my lab, and you can take your cell phone and photograph a particular food item and the app immediately places that food on the chart so you'll know what zone you'll be in if you eat it. These things are coming. We're using AI. But it's purely patient empowerment. The patient themselves, the person themselves, makes the choices. No government, president, or king should ever tell people what and how they should eat. The patients should be familiar with this and have the knowledge to know — I'm going to test what I think.
People say to me all the time, "Just tell us what we can eat." Eat whatever you want. You figure out where on the chart you're going to be, and then you'll know. People say, "Well, I can't eat a ketogenic diet." Our group in Greece — tremendous success in keeping glioblastoma patients alive. What was the diet? It was a calorie-restricted Mediterranean diet. Salmon, sardines, olive oil, avocado, and exercise. This is a bioenergetic road map to health.
Specific Dietary and Environmental Factors
Steven Bartlett: What about high fructose corn syrups and refined sugars?
Professor Thomas Seyfried: Oh man, that's the worst kind of crap. You don't take that.
Steven Bartlett: What about industrial seed oils — canola and soybeans?
Professor Thomas Seyfried: I don't know specifically. But every — there's another thing too. You and I are different. We have individual metabolisms. Age, race, sex — all kinds of things determine what and how you live. I can't be sure what you eat and what I eat or what exercise will put us on the chart.
Steven Bartlett: Synthetic pesticides. I was reading here that it increases the chance of lymphoma by a staggering 41%.
Professor Thomas Seyfried: They all damage oxidative phosphorylation, putting the cell at risk for compensatory fermentation and disregulated cell growth. The problem is the field doesn't understand what I'm saying with respect to the origin of cancer — how it happens mechanistically, how this organelle controls the life of the cell. They don't know enough about the biology and biochemistry of the mitochondria. You ought to get guys on here like Nick Lane from England, Doug Wallace — these are mitochondrial biologists. They understand this kind of stuff.
Fasting, Hyperbaric Oxygen, and Other Interventions
Steven Bartlett: Fasting protocols.
Professor Thomas Seyfried: Intermittent fasting. Do you ever try it?
Steven Bartlett: Yeah.
Professor Thomas Seyfried: What do you think? You liked it?
Steven Bartlett: It depends how long you're talking about.
Professor Thomas Seyfried: Okay, let's go a week.
Steven Bartlett: I've not fasted for a week before.
Professor Thomas Seyfried: You know what they call "the wall"? This guy just sent me his book — Viral Simek. He says people share things with me. The wall is after about three days of not eating, just drinking water. You hit this wall and it's like, "Oh man, I just can't deal with it anymore. I can't sleep at night. I've got the jimmy legs. I've got all kinds of problems. Screw it, I'm not doing this." He found out that if you sip just tiny amounts of grape juice, you can get through the wall.
What we do for cancer patients in the way we design our clinical procedures — we do a zero-carb diet for about a week while the body is readjusting, bringing them out of the red zone and into the yellow zone. You can't believe the power of glucose as an addictive drug on the brain. It's unbelievable — it's like cocaine. When you start, you start shaking. But if you don't eat carbs and just eat meat or whatever to keep you in a low GKI, then when you jump off to water-only fasting, it's much less traumatic to the brain. You've gone through the wall of the gate, so to speak. Once you know how to get through the gate, you make this whole process a lot easier. And that helps people enormously, especially those who want to get rid of their chronic disease.
Steven Bartlett: Dr. Valter Longo's extensive research and clinical trials prove that fasting-mimicking diets drastically lower IGF-1, which triggers cellular autophagy and actually makes standard cancer therapies up to three times more effective by removing the metabolic shield of cancer cells.
Professor Thomas Seyfried: Yeah. Which is the waste products of glucose — the lactic acid and the succinic acid — that all goes down.
Steven Bartlett: What about hyperbaric oxygen? There was a study in 2013 that demonstrated that while the ketogenic diet alone significantly slowed tumour growth in systemic metastatic cancer mouse models, combining the diet with hyperbaric oxygen therapy elicited a profound synergistic decrease in tumour growth and drastically increased survival times.
Professor Thomas Seyfried: Yeah, we published that paper with Dominic D'Agostino. Hyperbaric oxygen will create oxidative stress in cells that do not have efficient oxidative phosphorylation — cancer cells. So you can kill cancer cells by oxidative stress. You can irradiate or poison them, or you can put a patient in nutritional ketosis and then put them in hyperbaric oxygen, and the cancer cells are selectively killed. When you irradiate somebody, you're damaging the whole body. But with hyperbaric oxygen in a ketogenic state, the cancer cells are selectively targeted.
And there's another thing, Steven. When you use standard of care — radiation, chemo, immunotherapies — the patient comes in and the treatment itself puts so much stress on the body that the body itself goes into the red zone. The treatment is strengthening the tumour.
Steven Bartlett: You're not against chemotherapy, though, are you?
Professor Thomas Seyfried: No. I'm positive about it, but it has to be used in the right context. It has to be used when your body is in this state of nutritional ketosis. And you can use low doses so you don't force the tumour cell to become even more resistant to the treatment.
Microplastics, Forever Chemicals, and Water Supply
Steven Bartlett: The next actionable point is what you talked about earlier — microplastics and forever chemicals. In late 2023, the International Agency for Research on Cancer officially upgraded these forever chemicals, which are used in non-stick pans and food packaging, to a Group 1 carcinogen in humans — cancer-causing in humans — based on strong mechanistic evidence that they induce epigenetic alterations and suppress the immune system. So you ban the forever chemicals.
Professor Thomas Seyfried: This is a beautiful paper. I went back and took all of Otto Warburg's work, meticulously went through it, showed where he was absolutely correct and where he just didn't have the new information. I talked about the forever chemicals and microplastics — guess what? They damage the organelle. They get in, they cause ROS damage, they reduce the efficiency of oxidative phosphorylation, causing a compensatory increase in the utilisation of glucose and glutamine and disregulated cell growth. Everything comes back to this organelle. All chronic diseases and cancer are the result of damage to this organelle.
Steven Bartlett: The next thing is purifying the water supply. Heavy metals are found in local water supplies through runoff and are carcinogenic in some cases. The IARC classifies arsenic and cadmium as Group 1 carcinogens, and they're frequently found in unfiltered public water infrastructure. So you clean out the water supply as well.
Professor Thomas Seyfried: You know, all this stuff is coming into our water supplies — people flushing down all these chemicals, which then leach back into the water supply. And every one of the chemicals that has been linked to oncology or disregulated cell growth damages oxidative phosphorylation chronically. So we're bringing the entire focus back to: what can I do to keep this organelle healthy? Even if I'm exposed to these chemicals, if I can get into these zones like you're trying to do, this organelle has an incredible healing power in itself.
Metastasis and the Hybrid Cell Theory
Steven Bartlett: What is the most important thing we haven't talked about that we should have talked about, Professor Thomas?
Professor Thomas Seyfried: One of the things I want to talk about is metastasis.
Steven Bartlett: What's that?
Professor Thomas Seyfried: That's the spread of the tumour throughout the body. If you were to have a cancer that's just localised in one spot, the probability of developing a therapy that would be long-term is highly increased. The problem that kills people is the spread. If the tumour is in the breast and it spreads to the liver, the lungs, and the brain, you've got a problem. Lung cancer spreads to the brain, the liver. Most of these cancers that spread to the brain or other organs become very difficult to treat.
What we have found is that you have stem cell tumours. Stem cell tumours cannot metastasise. How do I know? Because I have stem cell tumours diagnosed with stem cell markers. I've grown them. They grow very aggressively, they get a lot of blood vessels, but they can't spread. How do you get spreading tumour cells in your body? The immune system comes in, recognises the tumour as an unhealed wound, and then fuses with the stem cells. Then you have these hybrid cells — macrophage-tumour cell hybrids. They are programmed to move around your body. They're very hard to kill, but we found they're remarkably sensitive — they're glutamine-driven. So we know they're glutamine-driven, and that's why metabolic therapy done the right way can target those metastatic cancer cells. Purging them with a little bit of immunotherapy to go along with it, you might be able to achieve what we call resolution.
My colleagues and I — including Joe Maroon — built the press-pulse therapeutic strategy. That's the way you press down the glucose of the tumour and then pulse to kill the glutamine, which targets the metastatic cancer cells, enhancing the health and vitality of the organs already infiltrated by the tumour.
A Message to Those Affected by Cancer
Steven Bartlett: I looked at our previous conversation, Professor Thomas, and it's quite heartbreaking because the comments sections are all people who are either struggling themselves with cancer, or a loved one — their wife, their husband — has just been diagnosed with cancer. Is there anything for those people that have clicked on this video that you want them to hear?
Professor Thomas Seyfried: Well, the thing of it is — when you have the science and you have the strategy to manage cancer effectively with minimal toxicity, not to say we can cure, but to say we can manage it — why is it not being done? That's the question. But to them, to those who've tuned in — these kinds of conversations are allowing populations to realise that their loved ones do not need to be sacrificed for the good of industries that are generally considered profitable. The profitability of the industries is based on your sickness. And a lot of those comments said, "Oh, you can't do anything." Yes, you can do something about it. When you're armed with the knowledge, and people ignore the knowledge, then there's a problem.
Steven Bartlett: Do people need to self-advocate to some degree with their care providers?
Professor Thomas Seyfried: I think so. That's a very delicate question. The oncologists have never heard of this stuff. They have never read these papers. They were never trained in medical school to know the biology and biochemistry of cancer. They were told it's a genetic disease.
Theories are so important in science. For 1,800 years, people thought the work of Aristotle and the mathematics of Claudius Ptolemy said that the earth was the centre of the solar system and all the planets and the sun revolved around the earth — the geocentric theory. Copernicus struggled with the Ptolemaic mathematics and realised that if he put the sun in the centre of the solar system and made earth just another planet, a lot of the mathematics made sense. Kepler came in and said these aren't circles, they're ellipses. Galileo took the telescope, saw the moons of Jupiter, and was able to predict where planets would be at a certain period of time. Then they took poor Giordano Bruno — you know about this guy Bruno? He was burned alive by the Catholic Church for challenging the geocentric theory. He became a martyr of science. So when you have an established power structure, whether it's a religion or an industry, challenging that can be very, very hazardous.
Steven Bartlett: Has it been hazardous for you?
Professor Thomas Seyfried: Listen, no. I do what I do because I just collect more and more data to support the work. Hazardous for me would be getting blindsided — somebody coming at me with a piece of new data that I have never considered. I don't sleep. I think about this stuff all the time to avoid the blind side. My students are on the alert for any paper that comes out saying cancer cells can burn fatty acids and ketone bodies. "Oh, really? Let's go back through and dissect out their control experiments." And you find in every case there was always some glucose and glutamine in the media, making it look like the fatty acids were being used. So that's what bothers me — getting hit with a piece of data that undermines our knowledge base. And so far we haven't had that.
We're standing on the shoulders of Otto Warburg, a giant in the field of biochemistry. He was thrown under the bus when everybody thought cancer was a genetic disease. This paper goes back and shows exactly where Warburg made his mistakes and where we have rectified some of that, bringing the whole field back to where it should be. It is a mitochondrial metabolic disorder, and we can account for all of the phenotypes and characteristics of that disease. Knowing that, logical people interested in helping others will take advantage of it. We're not throwing out all these toxic chemicals. We're learning how to use them in a different way. And that's where the success is going to come.
Actionable Takeaways for Patients and Their Families
Steven Bartlett: So let's conclude with an actionable takeaway for people who are suffering themselves with cancers, or have someone in their family right now who is suffering from cancer. What is the actionable takeaway?
Professor Thomas Seyfried: I think once this paper comes out, they can start taking action if they are motivated enough. They can read about this, and then try to — just like you're doing — get into these zones, and then work with their oncologists and knowledgeable people to treat them with standards of care, as long as they can remain in these zones. And then we do non-invasive imaging — PET scans, MRIs.
Steven Bartlett: So specifically, what you're saying is this paper — I will link it below in the comment section for anyone that wants to read it. This graph will be on the screen throughout this episode, so people can screenshot it. And the way that they test what their GKI index is — they can buy one of these Keto Mojo devices, which you can get on Amazon for $20 to $30. You prick your finger, it gives you the glucose reading.
Professor Thomas Seyfried: The new machines have a button — you push it and it gives you the GKI right away.
Steven Bartlett: And as you can see on here, this is an interesting way to sort of improve your management of some of these conditions.
Professor Thomas Seyfried: And then there's a challenge to get into those zones. I'm not saying this is easy stuff. A GLP-1 inhibitor — that's a hell of a lot easier than doing this.
Steven Bartlett: And I should probably say always consult with a medical professional.
Professor Thomas Seyfried: Yeah. A lot of people have a lot of comorbidities — diabetes, high blood pressure, hypertension, cancer. It's not a perfectly healthy person with cancer. Before you go in to challenge that, you need to know what you look like medically. You might have to be adjusted in some way. That's why the physicians working with this can do all that. I'm not in the clinical thing.
And there are some people who respond poorly to high states of ketosis because of comorbidities. Some people have carnitine deficiencies. Carnitine prevents fatty acids from being made into ketone bodies. Carnitine supplementation can help them, but you need a physician to know this.
What Gives Professor Seyfried Energy
Steven Bartlett: We have a closing tradition where the last guest leaves a question for the next. The question left for you is on the subject of energy. What in your life has brought you the most energy, and what was the biggest energy drain you've ever experienced?
Professor Thomas Seyfried: Well, this is bringing me the biggest energy — the whole concept. The idea that you have found — that mother nature has allowed you to look into the depths of the biology and biochemistry of how bodies work, and knowing how to take that and apply it to people that are suffering from all these different chronic diseases, and giving them the opportunity to change that. Because before that, it was mysterious. Now you have a quantitative opportunity. We have a lot of evidence. I think people should feel encouraged. I think we have given hope to the hopeless, and I think that's empowering.
The goal here is not to make a billion dollars. It's just to know that you've kept all these poor souls alive longer than they were projected to be. And that keeps us going. When we see more and more people coming to me — I get emails back from people three or four years ago, and I said, "Gee, I thought you were a goner." And they say, "I'm doing really well. Just came back from a vacation with my wife." Well, that's empowering.
And don't forget, Steven — all of our research money comes from private foundations and philanthropy.
Steven Bartlett: So is that a way that people can help? And where do they go to help?
Professor Thomas Seyfried: Travis Christofferson's foundation. In my papers, we have the foundations that support our work listed. There are occasionally people I know — when I give kits of information to people, I say please consider making a donation, only if it works for you. Don't charge them anything or ask them to pay something if it's not going to help them. If you were told you'd be dead in six months and six years later you're alive — maybe you throw us a few shekels into the foundation supporting our work.
Steven Bartlett: I'll link that foundation below in the comments section.
Professor Thomas Seyfried: We have a couple — on breast cancer, on general support for the metabolic approach. We have a lot going. We're very excited. You can see all the papers we've published. Some of them are in top journals, some of them are in newer journals, but the issue is we're publishing this.
Steven Bartlett: My thing is — great respect for science and doctors in the medical profession. Go get your information. Speak to your medical provider. There are so many tools out there now. Go and check for yourself.
Professor Thomas Seyfried: Well, I think in the oncology field, that's where we have this vast wasteland of misunderstanding. They don't understand these concepts. People who have done heart work and bone work and replacements — those people are at the state of the art with this kind of stuff.
Steven Bartlett: Well, the last conversation we had reached about 15 million people — on YouTube it's got 10 million views, and then across audio platforms it's got another five or so million views.
And it actually just creates a community of people in the comment section — people that are searching for hope. And some of them read through the comment sections and commented saying, "It was so nice to speak to other people in the comment sections about what I'm going through and how it feels from an emotional level." So this is something I actually wanted to say in this episode — if you're listening to this conversation now and you've gotten to this point, do feel free to go into the comment section and just offer some support and some love to other people who are struggling. It can be a very lonely experience the minute you find out you've got a diagnosis, and off you go into the internet, into podcasts, into AI to try and figure out what you can do. So do share things that have helped you, point at different resources that are rigorous, and offer emotional support to those in the comments section.
Thomas, thank you so much for all that you do. You're an absolute warrior for pushing the science into the world and for fighting for these people that don't have the tools. I don't think I've ever seen a comment section quite like it in terms of the gratitude that people have for the work that you're doing. It is remarkable work. Long may you continue to do it.
Professor Thomas Seyfried: Well, thank you very much. You play a very important part in this, because this information is not disseminated to the population, and it's the population of people that will eventually make the change. They're going to want this, especially when we keep publishing more and more case reports of successful cases. The system will change, and we just have to modify what we have to make it better. I have no plans of stopping this anytime soon. My students are all excited about this. They're learning about it at Boston College. Scientific literacy is so important for how you navigate through life. Thank you very much for your show, and we'll keep pushing this as hard as we can.