Main Topic In this episode of Oncology Unscripted, Dr John Marshall reflects on growing vaccine hesitancy and contrasts that with new reports that a personalized melanoma messenger RNA vaccine improved outcomes in a phase 3 study. MedBuzz In this MedBuzz, Dr John Marshall reflects on recent changes in prescription drug pricing and the rapid rise of GLP-1 receptor agonists, their long-term impacts, and how he handles answers to questions from patients about impacts on cancer outcomes. Interview In this episode of Oncology Unscripted, John Marshall, MD, speaks with evolutionary biologist Daniel E. Lieberman, PhD, author of Fed Up, about the connections between physical activity, nutrition, the microbiome, and cancer prevention.
Main Topic
In this episode of Oncology Unscripted, Dr John Marshall reflects on growing vaccine hesitancy and contrasts that with new reports that a personalized melanoma messenger RNA vaccine improved outcomes in a phase 3 study.
MedBuzz
In this MedBuzz, Dr John Marshall reflects on recent changes in prescription drug pricing and the rapid rise of GLP-1 receptor agonists, their long-term impacts, and how he handles answers to questions from patients about impacts on cancer outcomes.
Interview
In this episode of Oncology Unscripted, John Marshall, MD, speaks with evolutionary biologist Daniel E. Lieberman, PhD, author of Fed Up, about the connections between physical activity, nutrition, the microbiome, and cancer prevention.
Main Topic
mRNA Vaccine Advances Melanoma Care Amid Growing Vaccine Hesitancy
John Marshall, MD: Happy end of summer. John Marshall here with Oncology Unscripted, and I am so glad that you decided to waste a little bit of your time with me. What have you done this summer? Did you take a big trip to Europe, maybe, or did you just take some time off? Are you a beach person? Did you put your SPF on? Maybe you're there now. There are a lot of people who go out in August, particularly here in Washington.
I don't know if you know, but this is the lowest-traffic month in Washington, DC. But what have we done? This coming weekend, we're having an Indianapolis 500–kind of race in downtown Washington, where the current administration has taken an area right in front of the Capitol, in front of the Smithsonians and all of that, and built this racetrack that's going to happen on Sunday morning.
So, I guess those on the religious right are fine with having a car race on Sunday morning. They're going to close National Airport for 4 hours while the cars go round and round. They're worried that things are going to fall off of the museum shelves, and so they're really nervous about that.
Maybe there will be a bad car wreck. What is that going to do with 200,000 people down there watching it in the heat this coming Sunday? So, stay tuned for the Sunday night news to see what happened here in Washington. Hopefully nothing, and hopefully all goes smoothly, but we are a bit nervous here in Washington, which is why so many people have left town and traffic is low.
But it's also back-to-school time here in the DC area, and I'm sure it's the same where you are. And one of the news pieces that came out, of course, is that we all have to have our kids vaccinated in order to go to school. We check them. You have to have a reason why you didn't get them if you didn't get them, but there are requirements.
There are requirements for our staff here in the hospital to have certain vaccines every year. We're required to make sure we get them. But, of course, there is a major discussion going on in this country about whether vaccines are a good thing or whether vaccines are somehow a bad thing and are causing other downstream problems—worries about certain learning disabilities and all sorts of things that have been brought up that certain people are claiming are caused by vaccines.
And so, we now have new regulations here in this region. The federal government has put out new regulations that actually reduce the number of vaccines that children are supposed to get before they go to school. This is at the same time we're also seeing, in the next column over, the increase in measles outbreaks that is going on around the country. In the international pages out there, we're seeing all of these outbreaks of Ebola virus in Africa.
And I've been reflecting on my 34th year on the faculty, with residency before that. When I first showed up here, this hospital was full of a bunch of young men who were dying of HIV, of AIDS, and that's what I first learned on. And it was Anthony Fauci and many others who actually pushed through how to help develop new treatments against that virus and the struggle against that.
More recently, we've all lived through the COVID-19 wave. And so, for those who said it didn't happen, those of us with white coats on—I'm wearing mine today; I've been a doctor today—you know, we remember that it was not something that was fake. Our hospitals all of a sudden filled with people. We turned normal floors into ICUs, for example, so we could take care of this wave of people who were suffering and dying from COVID-19. We also remember the treatments of that and the development of a COVID-19 vaccine.
At the same time, we're reading over here about lettuce infestations from the parasite Cyclospora, and what's the federal government doing about that? Well, it's kind of dragging its feet as well in trying to intervene or go down and check it out to make sure that the food is safe. So, I am nervous about our current belief system about what's true in medicine and in health care, and what is not true or what's harmful out there.
Then, just for fun, there was a recent article around AI, artificial intelligence, creating a virus itself that could invade, right?
So, now we have created this AI over here that's not only invading itself but also is creating viruses that maybe are our undoing, ultimately. And then, at the end of this story, a very recent paper just came out. It's probably too late to invest in the stock because it already is affecting the stock price, if you will. But there is a messenger RNA vaccine—remember that one when the COVID-19 stuff was out?—that has just shown positive effects in melanoma. And this, of course, by Merck and Moderna, has just been announced—not the data so much, but the press release about how using that messenger RNA vaccine is, in fact, helping to delay recurrences and maybe, ultimately, help cure more people.
And I do wonder: if those people who were afraid to get the COVID-19 vaccine, messenger RNA vaccine, now have melanoma, would they also be afraid to get that one, even though it's shown in this randomized clinical trial to have improved outcomes? And so, I do think we have a very, very upside-down world when it comes to de-harnessing our immune system, exposing our immune system to as many things as we can, enriching our microbiome in a way that gives us an even healthier immune system.
And our interview this time was with Daniel Lieberman, who's focused on nutrition and diets and the impact on our health. And I think we, as health care providers, have really fallen behind in understanding more about the microbiome and how to feed and stimulate our immune system, even apart from the virus work that we have done before.
So, I am unsettled as we go back to school in the fall of 2026, with fewer children having vaccines, with more emerging resistant infections that are out there, and a public that's not sure which is the right way to go. But hopefully, we will have a good year ahead. Do your homework, kids.
And hopefully, a year from now, we will be able to say that we are indeed all a bit smarter and all, hopefully, a little bit healthier. John Marshall for Oncology Unscripted.
Med Buzz
Drug Pricing, GLP-1s, and the Long Game in Cancer Care
John Marshall, MD: Summer traditionally is a kind of slow time for new papers and new stuff that's happening in the business world. So our federal government did its usual thing, and we actually got a press release very recently that said, “Never before have we seen such a fall in drug prices.”
And of course, our current administration claimed that it was they who were totally responsible for all the good things that have happened in the world. Well, the reality, if one looks back, is that this story about drug pricing, brief history, was created by the second George Bush when we were trying to expand access to insurance covering drugs, oral medicines at your local pharmacy, particularly in the Medicare space.
And so there needed to be some deals cut, and one of the deals that was cut is that we agreed that we would not negotiate drug price. Of course, that started the current wave that has occurred where, when a drug gets FDA-approved, they basically can ask whatever they want, and insurance companies basically need to figure out how to pay that. So that's created this dramatic escalation in the price of drugs. Well, Biden, I don't know if you remember him, he basically was the first one that came out and said, “We've got to start changing this.” And he published a list of, I think it was 10 drugs that we're going to now negotiate price on as a sort of trial balloon.
In the next year, another list came out, and since then there have been increasing numbers of drugs that have been on the list where we, as a US government, the government and CMS Medicare, have a right to negotiate the price of those drugs. And that's essentially what the current administration is claiming as the victory is that we're now starting to see that having an impact on our overall budget in healthcare through a reduction in some very expensive drugs' prices.
I coupled that story with the fact that I spent the weekend with someone who, for the first time ever, I'd actually spent a weekend with somebody who's on a GLP-1 drug. And this is a good friend of mine who initially started taking it because of being a bit heavy, maybe a bit of prediabetes.
But because he doesn't fit the classic scenario, he basically is buying the medicine himself, at a decent cost, as you might expect.
Living with him for the weekend and eating three meals a day with him taught me something about these medicines: that he eats completely differently: what he eats, how much he eats, his need to focus on getting enough protein because his appetite has been turned down a bit.
He certainly has lost some weight, and his blood counts look better. So, the impact he was looking for, he's had, he's having with this medicine. But then I started to dig a little deeper on this, and what came out these past couple of weeks is that there's been this dramatic rise in the number of people in the United States who are taking GLP-1 drugs.
So, in 2024, what AI told me was that 3% of us in the United States were on these drugs. They were first founded in, like, 2005, so they've made their way along. But just a few, couple years ago, 3%, and now it's 12% of the US population on these drugs. So, that's a dramatic increase in these medicines. Now, so far, the stats say that about half of everybody who takes them stops them at about one year.
And as I think you all already know, when you stop them, you kind of revert back to what you were doing before. So, it's, it's only while you're taking the medicine. It doesn't fix it, and then you're done. It's only while you're taking the medicine that you have the impact. No question, we've seen obesity rates fall as a result of this.
So far, again, this is new; we haven't been following people for very long, and that's sort of my main worry here: that we haven't seen a big change in diabetes outcomes at this point. So yes, people get skinnier, yes, their blood sugars get better, but are we going to see the downstream positive effect with less cardiac and other problems, vascular disease, et cetera, from that?
So, people are changing their eating habits, a lot of them. And you know I'm all obsessed with microbiome and needing to eat the variety that's out there and you know, sort of that Mediterranean-based diet, full of plants. Yes, some protein, but full of a variety of plants. Also, what comes with these is actually muscle wasting, so we may be changing microbiome not for the better.
We may be changing our muscle mass also not for the better. But again, they're so new we haven't really seen the long-term impact. Where does this play in cancer? There have been several reports; patients have been bringing me their phone reports, where they see reports of GLP-1 drugs decreasing carcinogenic risk.
Well, that hasn't really turned into a real clear decrease in incidence of the disease. The things that cause the risk, obesity and other things like that, have fallen, and so the assumption is that we're going to see a decrease in cancer as a downstream result. So I've got patients on active therapy who want to also be on a GLP-1 drug, and I can't really justify doing that based on where we are now.
There also is some suggestion that they might have other anti-inflammatory effects that would help suppress tumors. So there is an emerging lore (that's all it is at the present) that these drugs might in fact help with regard to cancer downstream as well. So, in a way, it's kind of almost too good to be true on some level, and I'm nervous: when all of these people are taking these drugs for this long of a period of time, what will in fact be the actual outcome?
And as you know, I reflect back on past times that I've had, and it sort of reminds me of the opioid crisis. I realize it's different, but do you remember when pain was not a vital sign, because it didn't use to be? It became a vital sign because the companies who made the opioids, as part of what we later called the opioid crisis, said, “We need to have pain as a vital sign.”
And when I trained and when I was an early faculty member, there was no dose that was too high. You just kept going up on everybody. So I had lots of patients on very high milligrams of narcotics, and I had a palliative care program that was standing next to me that said, “Yep, that's the right thing to do,” only to later find out that we had created this sort of national pain crisis that was built on not the best research, if you will.
And so now I have maybe one person at a time who's on such high doses of narcotics, again, with that same palliative care team next to me, but we seem to be doing okay without those super high doses. And so I realize it's different, but it makes me think of these waves of sort of… They're not fads…There's science and there's intervention and there's ability to intervene, right, on these folks, but without a really clear understanding of where it's going to end up in the long game. So I'm not saying don't take GLP-1s. They're very useful in the right patient population. You gotta keep taking them, as best I understand. But I do think we need to watch very carefully over time: what does this do to our microbiome as we begin to understand more about that? What does it do to muscle mass? What does it actually do to long-term cardiovascular risk and other things that diabetes and obesity lead to, including increased risk of cancer?
So, fingers crossed, it is a medicine and a medicine approach that we will figure out and optimize for the right patient at the right time, and as a result, we will see less cancer, fewer other problems, and they'll be worth their weight in gold.
John Marshall, Oncology Unscripted.
John Marshall Interview
Exercise, Nutrition, and Cancer Prevention: A Candid Conversation with Evolutionary Biologist, Dr Daniel Lieberman
John Marshall, MD: Hey, everybody out there, John Marshall for Oncology Unscripted, and I am a very lucky man today that I get to interview somebody who's not only a brilliant writer, but one who has taken his experience and his knowledge and applied it to something that's in everyday use to all of us, frankly, out in the world, but also within the medical profession.
The reason I reached out to Daniel Lieberman is that my wife was reading in one of the national papers an article where he and his wife took on a variety of diets that everyone is convinced is exactly the right diet to be on for a long life. And they tried it for a while, and his description of how they felt with each of these diets really made me smile. And it was at the same time, on the same day, when several of my patients were like, “What should I be doing? How should I be eating? Is there some way to eat my way out of this problem I've got?” And I keep saying, “Well, maybe it's the Mediterranean diet,” and that was one of the conclusions that came out of this article.
And today, Dr Lieberman has published, just released today, a new book called Fed Up, where he really drills down on our nutrition. So, Dr Lieberman, with that very long preamble, thank you very much for joining us today on Oncology Unscripted.
Daniel E. Lieberman, PhD: No, it's a pleasure. Thanks for asking me, even though I'm not an expert on cancer.
John Marshall, MD: You are. You just don't know it yet. I think what we're going to find out is that you know probably more, or what you have learned is probably going to be as impactful on cancer as some of the things that I have learned over my career. But let's start. Your first main book, or one of your many books, was around exercise and the impact of physical activity. And we've had a recent paper that demonstrated that when colon cancer patients were randomized to receive either a pamphlet that said, “Go exercise,” or a personal trainer, there was an 8% increase in cure rate among the patients who got the personal trainer.
Talk a little bit about your interest in exercise and health, and how that might feed over to us in the cancer world.
Daniel E. Lieberman, PhD: I study the evolution of the human body and how and why our bodies are the way they are, and how that's relevant to health. And most of my research has been on the evolution of physical activity, and one of my arguments—the book you're referring to is entitled Exercise, and I titled the book that way because we make people exercised about exercise.
You know, we evolved to be very physically active. But exercise, I define that as discretionary, voluntary physical activity for the sake of health and fitness. And until recently, nobody did that. I mean, it's crazy, right? If you were a very physically active hunter-gatherer or a farmer who had to work hours and hours a day in order to get food, why would you go for a 5-mile run in the morning or lift weights in a gym that you have to pay for, right?
They would think we're mad, right? But the problem is that we live in a world now where people are physically inactive because of our jobs, because machines have now replaced human labor, and we're paying a price for it because physical activity is baked into our physiology, and an absence of physical activity is what we call an evolutionary mismatch.
We're not adapted to a lack of it. But here's the issue, going back to what you mentioned: We evolved to be physically active for two reasons and two reasons only: when it's necessary or rewarding. And just telling a patient to go exercise makes it neither necessary nor rewarding.
It has high efficacy but low effectiveness, in the words of medical science, right? We wrote a piece in JAMA recently, but if we want to help people be physically active, we need to take the time to talk to them about what their barriers are and why they are finding it difficult.
Is it time? Is it stress? Is it the fact that they're overweight, or they're unfit, and they don't enjoy it? How can we help them overcome those barriers? Because it takes time and effort, and the results aren't immediate, and it's not a magic bullet, even though we often advertise it as such.
It just reduces your vulnerability to a wide range of diseases, and, of course, cancer is a major, major one.
John Marshall, MD: Coming back to the exercise and now Fed Up with what we're eating, I keep coming back to the final common pathway: some alteration in our microbiome that maybe even the exercise is in some way—how do we translate that into, like, cellular health? And is that through the microbiome? Or what were your conclusions there around exercise and health?
Daniel E. Lieberman, PhD: So there are a lot of pathways, and one of them, of course, is through the microbiome. Obviously, diet has massive and immediate and huge effects on the microbiome. What you eat can change your microbiome in a matter of hours, actually. And we know that some diets, diets rich in sugar and rich in red meat, cause changes in the microbiome that we know are linked to pathways that are involved in cancer.
For example, carnitine in meat causes the microbiome to produce a molecule called TMAO, which is well known to be carcinogenic, and is one of the reasons why there's a dose-response effect between red meat in the diet and rates of cancer.
But exercise also affects the microbiome. In fact, my colleague here, Rachel Carmody at Harvard, has done this one really neat experiment. I was involved in the experiment, too, but we tracked a bunch of runners who ran a marathon a day across the United States. I was looking at their biomechanics, and a colleague of mine, Aaron Baggish, and I, we looked at their hearts.
We CT scanned them before and after. Rachel studied their poop, right? And compared their microbiomes with those of the people who were accompanying them across the way. Those were the controls as they moved across the country. And physical activity has major effects on the microbiome in ways that appear to be quite beneficial.
When you're physically active, you increase your throughput rate, so you're actually changing what gets to the microbiome. You're changing bile production. All kinds of things are going on that result in shifts to the microbiome. And so it adds another dimension to our knowledge of the microbiome, which is that not only do our diets cause, say, microbiome mismatches, but lack of physical activity also seems to have some effects that have negative health consequences.
When you're physically active, I mean, every runner knows. I've never met a constipated runner. If they exist, maybe, you know, I'm sure there's somebody out there who's constipated, but it's pretty rare, right?
That means that there's faster throughput time, which means that the microbes in the microbiome are getting different food than if you're just sitting in your chair all day long.
Because what gets through the small intestine to the colon is going to be different. So that's just one of many… But, of course, another factor is the immune system, for example. When you're physically active, your bodies produce more natural killer cells and cytotoxic T cells, and we know that those cells are patrolling our bodies 24/7, looking for, among other things, cancerous cells.
And so I think that, and again, we don't have good data on the mechanism, but we have good epidemiological data on lower rates of cancer among people who are physically active versus sedentary. And we have mechanistic data showing that when people are physically active, it raises natural killer and cytotoxic T cells.
You combine epidemiological data with mechanistic data, and you have a pretty good explanation for why people who are physically active have lower rates of a wide range of cancers. So, both are important and in different ways and through multiple mechanisms. Energy is yet another one.
Hormone levels are yet another one. I mean, these are all multifactorial issues, and they have multiple causes, and it's hard to kind of, you know, draw simple one-to-one conclusions.
John Marshall, MD: We know it's complicated. Let's take you to your current book, the one that's just released today. You're having a busy day, my guess is today because of that. But what should I answer my patients when they say, “Doc, what should I be eating to help my health?”
Daniel E. Lieberman, PhD: First of all, there's treatment versus prevention, and I know more about prevention, right? And you look, I'm an evidence guy, right? I mean, I'm not going to take my advice from some book that claims to say that, you know, you eat this diet, it's got optimal health.
When you want to get… See, it's a red-letter word for me, optimal. Any diet that claims to be optimal, to me is overadvertised. That's a problem because no diet is optimal. Diets can be better or worse or have trade-offs, but you know, you and I are different. People in Beijing and Boston are different.
I mean, old and young are different. People have different genetic backgrounds. People are too varied and foods have too many trade-offs for there to be an optimal diet. But that said, study after study after study shows that diets that are high in red meat have a higher rate of cancer.
Diets that cause high levels of insulin, because insulin is clearly a pathway, part of the pathway that involves cancer, and diets that have a lot of processed food for reasons we don't totally understand. Junk food diets, lots of additives and all that kind of stuff are definitely associated with higher rates of cancer.
So, ultimately, the diets that come out ahead in terms of epidemiological studies as well as mechanistic studies are like the Mediterranean diet. Diets that don't have a lot of saturated fat, don't have a lot of sugar, involve mostly plants, aren't highly processed. And, you know, of course, the Mediterranean diet's the best studied of these diets because there's so many studies now, prospective, randomized controlled studies like the PREDIMED study in Spain, which they actually halted early.
This was 7,000 people in Spain. They actually halted the diet after 5 years, not because the Mediterranean diet arm was doing worse. Actually, it was the opposite. The folks who were not getting the Mediterranean diet were having higher rates of all kinds of diseases, and they realized it was unethical to continue the experiment and have a bunch of people not get the benefits of those who were on the Mediterranean diet.
That's just one example, right? The Nurses' Health Study. I could go on. So if you were trying to pick one diet out there which has been shown over and over again by high-quality, randomized controlled, prospective studies with mechanistic data behind it, I'd pick the Mediterranean diet. But I suspect a traditional Asian diet probably isn't much different in terms of its outcome.
I suspect a traditional Mesoamerican diet is probably pretty good. Probably the same for a traditional African diet. These traditional diets make sense. You know, not a lot of refined carbohydrates, so white flour. Have brown flour instead of white flour, have whole-wheat products, brown rice instead of white rice, olive oil instead of a lot of animal fat.
But most of us already know this, unless you've been bamboozled by some of these crazy diets out there. And then the other thing is that there is a lot of emphasis on weight-loss diets, right? And so people will go really, you know, insane over this particular weight-loss diet. But remember, weight and health aren't exactly the same thing.
They're related, but a weight-loss diet that helps you lose weight, there is… You know, the best ones are the ones that you can actually keep to, that you can sustain, because that's the biggest problem with most of these diets. But then once you've lost the weight, you'd have to figure out what you're going to be on for the rest of your life.
And again, I'd go with the evidence. I'd pick something like a Mediterranean or traditional Asian diet for which the evidence is clear and, you know, because you only got one chance. And here's the other thing about diet: It takes so long for the effects of a diet to manifest in your health.
You know, it's not immediate. You can, I mean, you can tell if you got diarrhea or nausea, et cetera, but cancer, that takes years. Heart disease, that takes years. So why are you going to wait and believe some expert who claims, you know, their particular weird diet is great for you versus the long-term, highly controlled studies that provide good evidence?
Me, I'm going to go with the good evidence because I, I don't, I'm not going to trust some person on TikTok or who's written some junky best-selling—
John Marshall, MD: Come on. That's where all the best information is. But that brings me to, you know, I'm really nervous about the GLP-1 drugs and how many people are now taking them for weight loss and diabetes control. And I spent the weekend with someone who's on one who had no appetite.
As a person who's watched fads over time and medical interventions, do you have a similar concern about these new drugs, or am I being a little overly nervous?
Daniel E. Lieberman, PhD: I'm pretty open-minded. Look, I just published a paper with Steven B. Heymsfield, MD, in JAMA on GLP-1s. One of my concerns is, first of all, for some people, they're the first opportunity they've had to overcome hunger. Because the big problem with dieting is hunger, right? When you go on a diet, you get hungry, and it's really hard to overcome hunger.
And now we have, for the first time, a medication that turns off or turns down your hunger, which enables you to actually succeed in the diet. So that's—And it's had some other mitochondrial benefits, et cetera. So there are good things about GLP-1s. But a few things scare me. So one of them is that a lot of people quit them.
So I think the last study I saw showed that about 60% of people tend to quit them after a year or two. So that's a pretty high—That's a pretty typical quit rate, actually, a low adherence rate. And, of course, those individuals, once they quit, their appetite is going to come roaring back, right? Because we know that that appetite has a sort of set or settling point kind of phenomenon.
And so, when they—And here's the other thing that's scary about that, which is that people on GLP-1s, a bit, a bit like, or much like those who have bariatric surgery, tend to lose a lot of muscle, because they're losing so much weight so fast. They're losing a lot of muscle mass, and that's going to put them at risk of sarcopenia as they get older.
And sarcopenia, of course, is a vicious cycle, right? Because once you become frail, you become less physically active. That increases the frailty. It's a major issue as people age. And so I'm kind of concerned that people who are on GLP-1s, if they're not doing strength training, they're at increased risk.
But other than that, I don't know. I think we're—It's an experiment that's being conducted in real time.
John Marshall, MD: Real time. And actually, those people with access, right? So this is a US-focused experiment.
Daniel E. Lieberman, PhD: Yeah, so—
John Marshall, MD: Not everyone has access like we do.
Daniel E. Lieberman, PhD: So we'll see. I don't know. I mean, there are benefits—everything has trade-offs. As an evolutionary biologist, that's my mantra, really. I mean, it's what my lab studies, and there are benefits and costs to GLP-1s. For some people, the benefits may surely outweigh the costs, but I think we need to be sensible about how we use them.
I think titrating the doses better may help some people with the nausea or the complete, you know, anhedonia and the complete loss of appetite. But also, here's the final thing. GLP-1s don't tell you what to eat. You still have to figure out what to eat. So you might still be eating junk food, but just less, right?
Although I gather that some people on GLP-1s just lose their craving for really energy-rich foods. So that can be—they're less desirous to eat junk food. But we still need to solve the problem of—because, you know, when you and I walk into a supermarket in the United States, there are 40,000 different kinds of foods in the average supermarket.
40,000 foods. That's an astonishing number, right? And we never evolved to cope with that. I mean, our ancestors—this is the start of my book, Fed Up—but our ancestors evolved to eat what they hunted and gathered. They didn't, they didn't get… It's like you didn't, like, 20,000 years ago, be like, “Hmm, gee, shall I have kudu today, or shall I have ostrich?”
You know? If they managed to kill a kudu, they'd eat kudu. If they managed to kill an ostrich, they'd kill an ostrich. But most of the time, they brought home plants, right? And then, once we invented farming, farmers don't say, like, “Gee, you know, should I plant artichoke this year so that in the spring I'll be able to have lots of art…”
I mean, they just, you know, they have a bunch of crops that work, and they ate what they hunt, what they grew. Now we're in this very weird world where we don't have to know anything about how to get our food. We have to know how to choose our food. And when there are 40,000 products in the supermarket and 60% to 70% of them are ultra-processed, the fiber has been removed, and that's another issue for cancer, obviously.
So fiber has an important role in cancer prevention. And they've got all kinds of, you know, emulsifiers and preservatives and whatever, and they're loaded with sugar and loaded with saturated fat. And, you know, guess what? We get into trouble. And so GLP-1s don't help us solve that particular problem, and we need to figure out in our country how to improve our food system and also give people more information.
So I do a lot of work in England, and in England, when you shop in a supermarket, a lot of the foods have a little green, yellow, or red label on them. It's like super simple. Green means it's probably very healthy. Red means it's probably not very healthy. Yellow means, don't eat too much. It's super simple.
You might have debates about what's green, yellow, or red, but why can't we do that in the United States? Just give people…
John Marshall, MD: Yeah.
Daniel E. Lieberman, PhD: Because we're bamboozled by the all-natural labels and the this and the, you know, if loaded with vitamin C and all that kind of stuff. Give people a little bit of information to help them because most people want to eat healthy foods, they just don't know what to eat.
John Marshall, MD: I have to go exercise, I have to feed my microbiome appropriately, which is what we're talking about here: what's the right mix of things to have a nice, healthy microbiome and lower our risks of diseases in general.
I'm just hoping, as a guy from Kentucky, that bourbon is good for my microbiome. I'm kind of counting on it. I don't even want your opinion on that, because it'll just ruin my day. But nonetheless, I have to thank you very much for giving us this much time, Dr Daniel Lieberman, author of many books, the most recent one launched today, Fed Up. Thank you very much for joining us on Oncology Unscripted.
Daniel E. Lieberman, PhD: My pleasure. Thank you so much for inviting me.
This transcript was generated by AI and lightly edited for clarity.