Saturated fat - What's the Real Story? Podcast with David Katz

DietPodcastBody FatHealthOlive OilCaloriesHeart DiseaseFat MetabolismDietary FatsHealth Performance

Ginny Robards

humanOS Radio Guest

David Katz, MD

Podcast Number


October 6, 2016

So many issues in our world are made worse when we unduly simplify complex subjects and overgeneralize. For example, Californian’s are surfers. Sure, California likely has a much higher prevalence of surfers than Montana, but the actual percentage of the population that surfs is very low. This is a fairly trivial example, but you get the point that making generalizations leads to inaccuracies. Somehow we run into this oversimplification issue all the time, and it can cause serious harm. These situations can lead to avoidable arguments – which can sometimes last decades or longer – with believers on both sides entrenching themselves firmly in an inflexible mindset that is impervious to logic. Instead of being dedicated to finding truth. And there is always an echo chamber of people who have bought into the same ideology. Dietary saturated fat is one of these subjects.

Saturated Fat

There are many different types of dietary fat. Some appear to have clearly beneficial effects on human biology in certain contexts, like olive oil, while others appear to impair health when they comprise too high a fraction of calorie intake over time.

Saturated fat has been called out for decades by health authorities as something we should monitor and limit. Recently, however, this idea has been called into question by several meta-analyses – a type of scientific study in which all the research on a subject is pooled and analyzed together to help determine what the weight of the evidence tells us on that subject. Both of these meta-analyses – one by Patty Siri-Tarino at Tufts and colleagues, the other by Rajiv Chowdhury at Cambridge and colleagues – concluded that there is no significant evidence associating dietary saturated fat with heart disease.

While the Chowdhury paper did have many methodological issues (that were pointed out by no less than eleven responses to the paper published by the journal after the fact), the point I’d like to make is that it’s the interpretation of the findings that matter most in this case. And once you’ve been walked through the evidence and what it means, you clearly see that we are right where we were over the last several decades: we should still limit certain types of saturated fat.

In the latest episode of humanOS Radio I interview Dr. David Katz (@DrDavidKatz), Director of the Yale-Griffin Prevention Research Center, President of the American College of Lifestyle Medicine, and Founder of the True Health Initiative, of which I am a Council Director. We discuss many things about the state of health today, but we focus on saturated fat and how to view it in the overall context of your diet. Enjoy!

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Dan Pardi - 00:00: Dr. David Katz, thank you so much for joining humanOS radio, I'm really glad to have you here.

David Katz - 00:00: It's a pleasure, Dan, thanks for having me.

Dan Pardi - 00:00: We've been corresponding a little bit and I have been a fan of your writing for quite a long time. Maybe we can start off and you can tell us a little bit about what you do and the different organizations that you're a part of, start there.

David Katz - 00:00: Sure, thank you, Dan. Writing actually has become a big part of it. I think that's because in effect, what I really need to do in my career, to advance the mission is reach people with knowledge that's readily available, but covered over by the din and the discord in our culture, and get people to realize how proximal and how luminous the prize is. I say that as a specialist in preventive and lifestyle medicine, so I trained in internal medicine. While I was doing that residency, and in the hospital a hundred hours a week, I couldn't help but see the forest through the trees. Here were all these desperately sick people we were trying to keep alive, basically, but we were never going to make them well again, that wasn't even the goal most of the time because they had chronic diseases we couldn't cure, we didn't want them to die on our watch and we wanted to do the best we could, but they were never going to be vital.

00:00: Yet, most of them never needed to get that sick in the first place, because they had stuff we've known how to prevent for decades. I went on and did a second residency in preventive medicine and the rest, as they say, is history. I run Yale University's prevention research center at Griffin Hospital in Derby, Connecticut where we study lifestyle interventions to prevent chronic disease. I'm president of the American College of Lifestyle Medicine, at the moment, anyway; my tenure ends soon. I'm founder of a global initiative called the true health initiative, which has convened a coalition of experts from over 30 countries to stand together and say, "We agree about the fundamentals of the lifestyle prescription that could add years to lives, life to years, and by the way, help save an in peril planet into the bargain."

00:00: As you say, I do a lot of writing on various platforms; The Huffington Post, US News and World Report, Forbes, LinkedIn, Very Well, and in several others, because really, the information is completely solid. We know exactly what lifestyle elements could prevent 80% of all chronic disease. We know exactly what would, truly, add years to lives and life to years, but somehow, we've got to get a critical volume to support that information so it reaches people and persuades people. A lot of my career, now, is focused on getting that message delivered and again, I'm not trying to do it alone. I don't think any one voice can rise above the din. The true health initiative really epitomizes that effort to pool our voices and pull together, kind of like the Who's did in Horton Hears a Who, so we can break through and be heard because there is a luminous prize waiting for us on the far side.

Dan Pardi - 00:00: I think that for some, prevention just becomes once you start to think about that instead of traditional medicine and treating disease once it happens, just becomes their passion and purpose. I know it has for me, and getting exposed to that early on, it was like, "This is what I want to contribute my work, my efforts to." One thing that I've thought has been really needed in our world is really accurate scientific journalism. Either if you're a doctor, oftentimes you're treating patients, if you're a researcher, you're doing research and you're publishing, but somebody to translate, "This is what this science means." So that mainstream people, and also doctors, other health professionals, can really grasp on, understand, work from, best possible knowledge, is vital. I think we need more of that and I really appreciate the fact that you're doing that. It's a tireless effort, but your writing is really clear and filled with things that are soundbites that can take a big idea and actually turn it into something that you can grasp quickly, so nice work.

David Katz - 00:00: That's very kind, Dan, thank you. You made a couple of key points, first, prevention versus treatment. I agree with you, but on the other hand, as an internist who's taken care of patients for 25 years, one of the mistakes I think we sometimes make is we get very enthusiastic about the power of prevention, and rightly so, but it can sometimes sound like we are denigrating clinical medicine, and I never am. I've been there, I've taken care of patients in the ICU and on the medical wards, and like, I think just about everybody at one time or another, have been at the receiving end.

00:00: I've had orthopedic surgery and I've been treated for acute infections. I had a miserable case of a tick borne illness called anaplasmosis and I was extremely grateful for the antibiotics that got me back on my feet. Medicine as medicine is really good stuff, but it's limited to the treatment of disease, for the most part, whereas lifestyle as medicine can cultivate wellness at it's origins. They're parallel propositions and both are noble callings, the problem has been, we've had a preferential focus on disease care and we called it healthcare while doing almost nothing for actual healthcare and that has to be fixed, because there's so much at stake.

00:00: In terms of journalism, I think you made an excellent point. Docs in practice are busy seeing patients. Maybe the general public has this fantasy that after 12 hours in the clinic, they go home and read for eight hours, but the reality is that a lot of busy docs, they scramble to try and keep up with a few key journals, but a lot of their medical news they get from the New York Times or the Huffington Post, or something that they see online, and they get swept up in the pop culture assessment of what something means. You're absolutely right, if the quality of the journalism isn't good, we can see doctors massively misled.

00:00: The researchers who are populating the literature, they tend to be working in very narrow niches. If you want to succeed as a biomedical researcher, generally the best path to a Nobel Prize is to spend 30 years studying one molecule, just about. Highly, highly expert, but a great deal of depth, not much breadth, so they, too, are subject to the interpretations of the media in any area outside that very narrowly defined expertise. If the quality of medical journalism isn't good, it's not just the general public that can be misled and confused, it really is the professionals, too.

00:00: I'm pleased to say, and I appreciate the compliment, I'm in some great company. I think Sonjay Gupta at CNN is terrific, highly qualified, very thoughtful and very careful. I think Jim Handling, who's a doc and a senior medical editor at the Atlantic is great, and there are a number of others. It's proud company to be in, but we do have a lot of work to do, and we are outnumbered by the people who do very irresponsible medical journalism, creating confusion and ultimately, conspiring against public health.

Dan Pardi - 00:00: That, as well intentioned as it might be, I've often been very frustrated, not at the fact that somebody's trying to be helpful but is wrong, but is sometimes with the extreme confidence to dismiss the medical community's consensus in favor of their own opinion, which can oftentimes be associated with some sort of financial reward on the back end.

David Katz - 00:00: For sure. The other thing is, another key point, Dan, and you're making lots of them today, Bertrand Russell, among his famous witticisms said, "The whole thing wrong with the world is that fools and fanatics are always so sure, and wise people so full of doubts." You're actually right, the journalism, if we want to call it that, and these days it doesn't really have to be journalism, it can be somebody's blog, basically social media feed with no filter, no editor, no journalistic qualifications. The people who are the most sure they're right, no offense, but they tend to be fools and fanatics.

00:00: If you're a real scientist, you're never absolutely sure of anything. When you are sure, what you're sure of is broad themes as opposed to very specific points, of "This is definitely better than that." Very, very rarely hear true scientists get into that. Unfortunately, if you're at the receiving end of this, again, out in the general public looking for some guidance about health, diet in particular, where I focus much of my effort, you've got scientists who are routinely saying, "Well, it's a bit of this, and a bit of that." Then you've got some fool fanatic or prophet hound who says, "This is absolutely the way it is, I know something nobody else knows or is willing to tell you." It's very persuasive. That's the classic huckster on their [inaudible 00:09:12] selling snake oil, it's just the new age version of it.

Dan Pardi - 00:00: There's a quote from Daniel Conoman that I absolutely love, and when I read it, several people had popped to mind immediately, but it's from the book Thinking Fast and Slow and it's, "A story's believability has much more to do with it's consistency than it's completeness. So, scientists tell complete stories." As you alluded to, it's a little bit of this, and it might be this, and you're never quite sure if you're listening, and you're trying to figure out what to do yourself, of what to do. Those that tell a very consistent, clean story that's full of confidence, there's a reason why some of those people rise to prominence, even, and I think it's a bit touching into a unique human trait of following that person who knows the answer.

David Katz - 00:00: I agree completely, and yet, we are invited to learn from the follies of history so we don't just keep repeating them. Nutrition really serves up a precautionary tale, if anything does. We thought we were told to cut fat, we cut fat, and got fatter and sicker, why? Because we didn't improve the quality of our diets, we ate low fat junk food, and then we were told to cut carbs and we ate low carb junk food and got fatter and sicker, and now we're eating gluten free junk food and getting fatter and sicker. Unfortunately, it does become quite clear over time that these consistent but incomplete stories, do not help us, they don't take us where we want to go. There comes a time when we need to say, "There is stuff we take seriously. There is stuff where we actually look for a complete story, because we know it really matters."

00:00: The kind of stuff I'm thinking about, Dan, would be educating our children. Somebody could come along and say, "Psst, come on over here, I've got a shortcut for you. You don't have to send your kid to school for all these years. Basically, I've got this special decoder ring, they just need to wear this for three hours and they'll just skip over all of that." We're not going to believe that, because we know the truth. We take managing money seriously, we all know that get rich quick schemes are the stuff of sitcoms like the Honeymooners, and yet the very same people who have more than enough common sense to reject get rich quick schemes, line up and reach for their credit cards any time there's a get healthy quick scheme, or a lose weight quick scheme.

00:00: We have to get past that and minimally, start treating health with some of the respect we show to treat health like wealth, treat health like education, treat health like our careers, things that we know require cultivation over time, that need to be taken seriously, that generally, we invest in to get the returns we're looking for, and we know that a complete understanding, a complete story, really does matter. It's not that glossy pitch that's perfectly consistent and sounds a lot like Dumbo's feather. That's what it is, it's Dumbo's feather, it's a false promise.

Dan Pardi - 00:00: You see this in, today, there's these bio hacks. My mind, I've kind of gone back and forth, are they good or bad, and so I decided to define what would a good hack be, is this efficient and effective techniques and tools that help address something important? That's great. Bad is, short term focus ploys that offer solutions of dubious merit issues that are either real, perceived, or manufactured.

David Katz - 00:00: Exactly. The other thing is, these days, because everybody can impersonate a journalist, there's just a volume of noise. We don't just have the problem of needing good medical journalism, we actually need new mechanisms to rise above the din of bad information. Some of it's well intentioned, but just wrong. Some of it is just seriously misguided because they're people who put their ideology ahead of [inaudible 00:13:00] they don't really know the data, but they know what they want to be true. There's no question, there's a significant component of profit ahead of public health; entities that know the truth, but are playing fast and loose with it because there's profit in that. In the age of the blogosphere, the volume of all of that, it's deafening. No matter how good your information, no matter how credible, you still have to manage to be heard of the din, and that really is a new challenge.

00:00: There's so many misleading memes these days. These days, there's all this focus on the notion that we've been advising people to reduce their intake of saturated fat, but the real culprit was sugar. The reality is, we've been advising people for decades to reduce their intake of both the usual sources of saturated fat and sugar. It's amazing how many people seem to be peddling books these days that pretend they discovered the harms of excess sugar last Wednesday, but the reality is there have only been official dietary guidelines in the United States, Dan, since 1980, so about 40 years. In the 1980 dietary guidelines for Americans, the whole report was distilled down to seven key takeaways, bullets, that basically this little diagram that says, "Here's the gist of the report." Number five was, "Eat less sugar." It's been prominent in dietary guidance for 40 years. The problem hasn't been the message, the problem is we haven't been paying any attention to the message, and we keep getting duped into doing silly things that just make the situation worse.

Dan Pardi - 00:00: It is sad, and you mentioned that there's always this bad version of something that's now that's popular. Comes into existence, there's an excitement about it, you haven't heard of it before, and then people I think put a lot of hope in there, and then an industry builds around it, and then it always gravitates towards energy density and essential, junk food, that has the gluten free brand, there's just always a way to shift the problem, and the problem persists.

David Katz - 00:00: Actually two elements, first of all, there is no single nutrient focus that the food industry can't exploit, it just becomes a halo that they can put over junk food. Again, these days, there's the cottage industry and gluten free junk food or non GMO junk food, just as we've had cottage industries and fat free junk food, low carb junk food, and on and on it goes. Any one nutrient does not capture the essence of a high quality diet, it's just putty in the hands of big food, which exploit the halo effect and profit from it.

00:00: The other thing is, Dan, that sometimes these epiphanies, it's not something we haven't heard before. We've got another problem, and that is extremely short attention spans. It's always been an issue, but frankly, our attention spans just keep getting shorter and shorter as we're overwhelmed with electronic information and gadgetry. For example, Atkins. The Atkins diet went into the stratosphere in the early 2000's, with a little bit of help from Gary Taubes and his coverage of the diet on the front page of the New York Times magazine.

00:00: The books that were being profiled then, which came out in the 1990's, were a complete, almost verbatim redo, of books that Atkins originally published in the 1970's. Pretty much all that had changed between what he said in the 1970's, which obviously didn't do public health any good, and what he said in the 1990's, was that the people who had seen the books in the 1970's had forgotten all about it. It used to be a 20 year cycle, then it was a 10 year cycle, then it was a five year cycle, and frankly, now, I think it's a 20 minute cycle before we've forgotten what we thought we knew a little earlier today, and are ready to buy it all over again. None of this stuff actually is new. The current focus on sugar, you can see videos on YouTube of Jack Lalanne. Now how the heck Jack Lalanne made YouTube videos, I have no idea, but anyway. You can see videos of Jack Lalanne on YouTube, basically inveighing against the harms of excess sugar from 70 years ago. None of this stuff is new.

Dan Pardi - 00:00: I'm going to write the new new Atkins diet, because I'm going to take a killing.

David Katz - 00:00: You could, have I got news for you; I've had that offer. Several times in my career, I've had publishers approach me because of my stature and platform and following. They sort of told me, "This is the popular concept du jour, you could write the next big book on this topic." There was only one problem; it was BS. I was never willing to do it and consequently, the books that I have written haven't sold nearly that well, but they tell the truth, that's the good news.

Dan Pardi - 00:00: You got to start off by saying "The industry didn't want you to know." A lot of conspiracy, a lot of people working against you.

David Katz - 00:00: That's right, that's right. I am the renegade genius who propose the truth that either no one else knows or is willing to tell you. It's a formula, it's absolutely a formula. The other thing is, and a good example of this is a book like Grain Brain by David Perlmutter. First of all, these are people with medical credentials. What they do, and you've got to be extremely well informed on the topic to know this, is they cite the literature selectively.

00:00: If you're going to make the argument that the way to avoid dementia is to not eat grains, you have to ignore the vast literature that associates whole grain consumption with basically every conceivable good health outcome, including longevity and the avoidance of dementia. What you do, is you selectively cite only the literature that supports your hypothesis, but because you're citing the literature, it makes you sound very erudite and of course, the average reader of that book doesn't read the scientific literature in the first place. Maybe you've cited 200 studies, 300 studies, it sounds like an incontrovertible mass of evidence.

00:00: What the reader doesn't know is for every study you cited that supported your hypothesis, there were 10, or a hundred, or a thousand arguing the other way, and you very carefully ignored all of those. There's a formula, and it is "Promise the moon and stars. Dumbo's feather will get you there, there's a magic silver bullet, and there's usually a scapegoat, and there's a conspiracy theory, and only I know the truth, or only I'm willing to tell the truth, and then I'm going to selectively cite the literature and you're never going to know about that, so it's going to all sound very convincing and erudite and round and round we go."

Dan Pardi - 00:00: In our manifesto, which always sounds a little funny to say that, but we say we're about a process, not even a position. The position can change, slightly here and there, but I'd rather follow a process to arrive, with more confidence, at a recommendation or an idea. That's why with the courses we're making, we're not trying to be necessarily comprehensive to communicate with people, because it's asking people to do too much. What we're trying to be representative of what the comprehensive literature base says, what does the weight of the evidence say, let's [inaudible 00:20:05] on that.

David Katz - 00:00: Exactly, and if you approach the mission without bias and without trying to sell a particular answer, that's exactly the right way to do it, Dan. You follow the weight of evidence, it's usually quite clear. By the way, we've been talking around this, and for people listening, I think we ought to get it out there; the fundamental truths of a health promoting dietary pattern, are perfectly clear. They're supported by a vast amount of science, by [inaudible 00:20:31] by a global consensus of experts, and they play out in the real world in places like the blue zones, which I suspect people have heard about, where the world's longest lived, healthiest people, reside. They play out in the north Karelia project, where what we know was turned into a community wide intervention, that slashed rates of heart disease by over 80% and added 10 years to life expectancy over the last 40 years, and those fundamentals are that your diet should emphasize vegetables, fruits, whole grains, beans, lentils, nuts, and seeds, and water for thirst.

00:00: You want to eat fish and seafood, that's a good idea for you, I'm not so sure anymore it's a good idea for the oceans, but I would definitely put that in there for human wealth, we just have to make sure that our fish [inaudible 00:21:16] are sustainable. Everything else, really, is discretionary. You want to eat eggs, eat eggs. If you want to eat chicken, eat chicken. When you start getting into animal products, you have to be very careful about how the animals are raised, and fed, and treated. I don't think anybody wants to put cruelty on the menu.

00:00: Once you get into eating mammals, so now we're talking about meat, and in particular, beef, the environmental impact is a huge consideration. As we're pushing 8 billion homo sapiens on the planet, and we're all looking out and watching the glaciers melt, we really have to take very seriously, issues like preservation of our aquaphors, stabilization of the climate, land use, biodiversity, the planet is in peril. Even if we had doubts about the role of meat in human health, we have an overwhelmingly convincing environmental argument to eat less meat and eat more plant predominant diets.

00:00: When you do all that math, it's a clear message, and by the way, in terms of the details, does it mean eat less saturated fat, yeah, because a diet rich in vegetables, fruits, whole grains, beans, lentils, nuts, and seeds, is just naturally pretty low in saturated fat. It doesn't have to be low in total fat, because the nuts and seeds and olives and avocado, and if you eat fish and seafood, all relatively high in fat, but healthy on saturated fat, but it's low in added salt, because you're not eating processed foods, it's low in added sugar because you're not eating processed foods, it's low in added sugar because you're drinking water instead of soda, all of those specific nutrient ills get fixed if you get the basic foods right. Wholesome foods, sensible combinations.

00:00: Just to be clear, Dan, this is something I've devoted many years of my life to, but I've also written three editions of a leading nutrition textbook that's widely used in medical schools, and the most recent of those editions came out in 2014, has close to 10,000 scientific citations, and I say that both to make sure people realize they should never write a textbook, because it's just horribly, horribly painful.

00:00: The main point is that it's sort of an obligatory view from altitude, you can't do that work and not look from on high at all of the evidence and consider it fairly. It's just incredibly clear. Vegetables, fruits, whole grains, beans, lentils, nuts, and seeds, olive oil, avocado, water for thirst, it's just a short list of priorities. If your diet is mostly that in minimally processed form, you're going to be fine. If you want to be vegan be vegan, if you want a mediterranean diet fine, if you want a flexitarian diet, fine, all sorts of variations on the theme, but the theme is perfectly clear.

Dan Pardi - 00:00: Let's drill down a little bit on fat. This is a topic that I think does inspire a lot of confusion, or at least it provides an opportunity for other people to come along, and say, "Hey, they were wrong this whole time." I think one of the big problems with talking about something like fat, a class of nutrients, when we talk about things monolithically, as though, "Drugs do this, or fats do that." You really run into trouble.

David Katz - 00:00: Dan, you're just nailing it today, that's a beautiful illustration, "Drugs do this." What a silly thing to say, right? Everybody knows, there's a vast range of drugs in any pharmacy, they do very different things, they have very different side effects. Summary judgement about fat is just about as silly as summary judgement about all drugs, I think that's a beautiful comparison. When you get into the specifics of different kinds of fat, then it would be like saying, "All antibiotics are exactly the same." Or, "All painkillers are exactly the same." We've got saturated fat, we've got monounsaturated fat, we've got polyunsaturated fat, and within those classes, there are lots of individual members with lots of individual properties. We could get into the details of this, and we probably should talk a bit about saturated fat in particular, because the confusion there is almost boundless, but the simple reality is, let's go back to the beginning of the fat fixation. These days, it used to be that everybody credited Ancel Keys for focusing our attention on fat. These days, more often, he's being blamed for it.

00:00: The reality is, that what Keys did, whether you love him or hate him, the historical reality is he looked at different populations and their rates of heart disease, in particular, he was focused on, but other cardio-metabolic disease, and looked at variations in lifestyle to account for that, he was an epidemiologist. Essentially noticed the populations that were eating lots of plants and less meat and dairy in their diets tended to have much lower rates of heart disease. This sort of got translated, ultimately, into shorthand, initially, less saturated fat, and then further truncated into low fat diets.

00:00: At the time, that that advice first started to capture our imagination, the only way to reduce dietary fat intake was to eat naturally low fat foods, because low fat junk food hadn't been invented yet. There were no Snackwell cookies when Keys first offered up his advice. What are the naturally low fat foods? Vegetables, fruits, whole grains, beans, and lentils. Basically, Keys was saying, if you eat more of that, it's probably going to be good for you, and you know what? It's absolutely right. If we only look at the research done since Ancel Keys, it would prove that point. If Keys had never lived and never said a word, we would still know exactly what we know about those foods being good for health and reducing rates of heart disease and everything else.

00:00: We got to essentially a dumbed down message, just got fat. It got perverted into Snackwell cookies by big food for prophet, and then we wound up thinking that these leading scientists told us to eat Snackwell cookies. That's just nonsense. If anybody can find me the quote where Ancel Keys, or pick anybody like [inaudible 00:27:19] tells you to eat Snackwell cookies, I'll give up my day job and become a dancer, for crying out loud. We basically just dumb down the message and then we keep doing it. These days, there's a particular focus on saturated fat and the idea that we got it wrong, but it's just not true.

00:00: Essentially, the studies that are cited most routinely, I don't know how deep in the weeds you want to go, Dan, but there are actually two meta analysis that everybody who thinks they know that saturated fat is good for us now, tend to cite, obviously without having actually read them, one was by Siri Torino [inaudible 00:27:57] in 2010 and the other was by [inaudible 00:28:00] in 2014. To save ourselves a lot of agonizing detail, we can simply say this; effectively, what both of these review papers concluded, looking at the mass of evidence, was that when you compare the high and low end of saturated fat intake in the US and other developed countries, you tended to see exactly the same rates of heart disease.

00:00: There are two key issues there. One, the high and low end of saturated fat intake were not very far apart, and were both pretty high, because in our culture we eat a lot of the sources of saturated fat, pepperoni pizza, and such. The rates of heart disease were comparably high both times, there's nothing in that that suggests saturated fat is good for us, basically what it says is when people ate high amounts of saturated fat, they had high rates of heart disease, and when they ate a bit less saturated fat, they had the same rates of heart disease. That begs the question; the people eating a bit less saturated, what were they eating instead, and we know the answer. They were eating Snackwell cookies.

00:00: The people in our culture who try to reduce their fat intake, it's not as if they were eating more brussel sprouts and lentils, we know exactly what happened, they ate low fat junk food. Essentially, what all this literature tells us is that an excess of added sugar and refined carbohydrate, and an excess of saturated fat from the usual sources, like processed meats and processed dairy, are exactly, commensurately, bad for us. We have discovered more than one way to eat badly, that's all any of this is really telling us. You juxtapose that with what we know about eating well; a mediterranean diet, or a vegetarian diet, where either your diet's low in fat or high in fat, it doesn't matter, but where most of the fat is coming from, nuts, seeds, olive oil, avocado, fish, seafood, very little of it is saturated.

00:00: By the way, if you want to bring the paleo diet into the mix, and I've had lengthy discussions with some of the world's leading experts on that topic, in particular Boyd Eaton who is arguably the founding father of our understanding of the paleo diet, the kind of meat our stone age ancestors ate is nothing like the kind of meat most people are eating today. The idea that "I'm paleo, therefore I can eat pastrami." Is just nonsense, there was no paleolithic pastrami.

Dan Pardi - 00:00: Thinking about those meta analysis, I had, when I was looking at the [inaudible 00:30:25] one, it's not the best analogy, but it's almost like if you're looking at hydration levels, and you're comparing how hydrated are you if you have seven to nine glasses per day, you're already in a range where you're probably well hydrated versus like one glass versus seven. [crosstalk 00:30:41]

David Katz - 00:00: Exactly, I think there were really two key blind spots in those papers, I think the more important of the two was, instead of what? If you replace saturated fat with sugar, it doesn't make you healthy. Duh, who would think that it would? On the other hand, if you cut back on deli meats and you eat more beans and lentils and vegetables and fruits, absolutely that will make you healthy, it will help. The first key issue is, instead of what? The other is, yeah, okay so what we're asking is as X varies, does Y vary and X is intake of saturated fat and Y is the rates of heart disease. If you say, as X varied, we saw no variation in Y, the obvious question is, well how much did X vary? As you say, very very little.

00:00: Everybody in these studies was at a pretty high intake of saturated fat. The high end and the low end were both high and not very far apart, and you're exactly right. It's like saying we're going to compare people who routinely drink seven glasses of water a day to people who routinely drink eight or nine glasses of water a day and gee, we didn't see any major differences there in mortality, what a stunning revelation that is. If X doesn't vary, it's not going to produce any variation in Y, and that's kind of non news except with regard to nutrition and how we role in our culture because almost every nonsense you can peddle becomes nutrition news.

Dan Pardi - 00:00: I feel sorry for people out there that are interested in health, that are reading about this, because what you hear is that the high and low range of saturated fat showed no difference in coronary heart disease and it's just misleading, because the story that you're telling is accurate, understandable, and it just does people a lot more good. It's like a face palm.

David Katz - 00:00: It is a face palm, and yet, i think the reason for it is the obvious one, people like meat and I understand. I think we are constitutionally omnivorous, our species has been omnivorous for a very long time. There are two major problems with that, one is the kind of meat we're raising today is nothing, compositionally nothing, like the meat we're adapted to eat, but two, back in the days when we were adapting to eat meat, there were a hundred million or fewer homo sapiens on the planet, there are nearly eight billion now, it's a different day, a different set of priorities. We cannot be carnivorous.

00:00: I was very privileged to share the podium with Boyd Eaton and for those who don't know, I think really our focus on the paleo diet began in 1985 with a seminole paper in the New England Journal of Medicine by Boyd Eaton and his colleague at [inaudible 00:33:26]. They've populated the peer review literature with great stuff on the topic ever since. Anybody who knows anything about the paleo diet has learned it, in part, from Boyd. Boyd was saying, "Look, I like meat, I think we're hardwired to like meat, and it's just too damn bad."

00:00: What we can do is use our adaptations to a stone age diet to inform some of what we do in the modern age, but with nearly eight billion of us on the planet, we've got to get that protein mostly from plant sources for the sake of the planet, if not for our own health. Frankly, it pertains to both. If we are hardwired to like meat, and you deliver the message, "Hey, I've decided that the truth is, bacon is good for you." It's not very difficult to sell your book. It's a winning formula, but unfortunately, it's wrong.

Dan Pardi - 00:00: Reduced down to the very popular "Gluten is bad, bacon is rad" t shirt that is worn. I've been a part of ancestral health symposium since the beginning, my mentor, [inaudible 00:34:30] in the Netherlands has been writing, actually, about the subject for a while. I heard about it from him first, found out that there was more of a popular movement. The first one was at UCLA, then the next year was at Harvard. We celebrated a speaker's dinner at Boyd's house on the third year. It's a concept that's really compelling in a lot of ways.

David Katz - 00:00: Absolutely. I routinely point out, Dan, we're having this meandering conversation about diet and lifestyle and health. I think one of the relevant questions people could ask themselves is, how is it that we even could be clueless about the basic care and feeding of homo sapiens yet know what to feed horses and sheep and tropical fish and koala bears and giant pandas, does it even make any sense? When you go to visit a zoo, if you think, "Gee, how do they know what to feed these critters?" I'll tell you one thing, they don't run randomized clinical trials where they try the koala bears on hunks of wildebeest and see how they do. It's simpler than that. They give all the animals food closely related to what they eat in the wild. That is the power of adaptation. Giant panda's survive on one of the least nutritious foods on the planet, bamboo, and they can survive on absolutely nothing else. Why? Because they're adapted to eat bamboo. Eucalyptus leaves? Terribly poor nutrition, and actually, pretty high in some toxins, but it's the only stuff koala bears can eat. Why? The power of adaptation.

00:00: I think the relevance of ancestral diets and our adaptations couldn't be any greater, but then we have to acknowledge, we're not in the paleolithic anymore and everything our stone age ancestors ate is extinct, plants and animals alike. What we have now is the opportunity to learn from those dietary patterns and use modern foods to try and approximate them, but we have to be honest. Most people who wave the paleo banner have no interest in eating bugs, they have no interest in eating a hundred grams of fiber a day, and if you read Boyd's work, one of the consistent conclusions is that our stone age ancestors got about a hundred grams of fiber a day, I don't know anybody who has that much time to spend in the bathroom, frankly.

00:00: They did hard, physical work every day, they covered miles, all of that. In for a penny, in for a [inaudible 00:36:55] you want to be paleo, be paleo. You eat only the flesh of wild animals, you eat a wide variety of plant foods, you eat no added sugar other than honey that you wrestle from the bees, you do a lot of physical word, you eat a hundred grams of fiber a day, and you're in the bathroom every five minutes of squatting in an open field. Otherwise, it's not paleo.

00:00: I think the opportunity to learn from adaptation, essentially, when we talk about ancestral diets what we're really talking about is the relevance of adaptation to all of biology. All I can say is "hear, hear, of course, it pertains to every other species, of course, it pertains to ours as well." We have to figure out what do we do with that information in a modern world where there are nearly eight billion homo sapiens, where the kind of meat available to most of us is not the kind of meat our ancestors ate. What do we learn and how do we use it? Honestly, I don't know that I've ever heard anybody address it better than Boyd Eaton.

Dan Pardi - 00:00: That movement is so much bigger than just the diet, although the diet is the most well known. When you think of paleo, you think of the diet. The ancestral [inaudible 00:38:03] movement is looking at light patterns, physical activity patterns, our relationship with microbes, our relationship with each other. That's, to me, the most exciting part. It's really not just the diet, but it's how does this framework, this mental understanding, guide modern day health directives, by helping us live more like our ancestors. That's cool.

David Katz - 00:00: That is really cool, I totally agree. There's a holistic element to our adaptations. On the other hand, it's interesting. I'm reading a book now on evolutionary biology called The Story of the Human Body by Daniel Lieberman who was a biologist at Harvard. Up until fairly recently, human stature, basically, peak height, was lower than during the paleolithic, suggesting that the source of nutriture was better for human need then than now. We have now surpassed paleolithic height, on average. We've obviously surpassed paleolithic life expectancy, for the most part. We've overcome a number of liabilities that we dealt with back then. We have a whole host of new ones. I think the critical piece is we can pass what we know about ancestral health through a modern filter, and maybe produce something that's even better.

Dan Pardi - 00:00: [inaudible 00:39:28] need to. I totally agree.

David Katz - 00:00: we have to be thoughtful about it.

Dan Pardi - 00:00: Absolutely, we have to look at the conditions of modern society, and not say, "Hey, we've got central nervous system preference to pursue energy density in a time when pursuing that was good, because we weren't surrounded by it, ubiquitously, all times of day." We need to use our minds, our neo cortex [inaudible 00:39:50] to make some better decisions and say, "Okay, what is the reality of our environment today?"

David Katz - 00:00: I'm accustomed to saying that the human brain is exactly the wrong size. Four of my best friends on the planet have four legs apiece, three dogs and my horse. Spend a lot of time with all of them, and one of the things that I love about their company is just their purity, the simple honestly. They want what they want, they like what they like, what frightens them frightens them. It's honest, it's transparent. Our brains could be a bit smaller and we'd be pure and simple like that, or they could be a bit bigger and maybe we'd figure out how to fix all the messes we've made, but they're right in the middle where we're just so good at messes and mischief. I'm hoping we eventually evolve past that, but we got to live through it in the time being.

Dan Pardi - 00:00: That's true. This is great, I want to talk about one more thing related to saturated fat, because we talked about how saturated fat is a class of nutrients, we can't talk about it as one thing. How things have not really changed that much over this period of time, information was distorted, abused by the industry, and then the blame fell kind of on the wrong shoulders. Now, how saturated fat is now having a resurgence of, "Hey, was it really that bad for us in the first place?"

00:00: There was a few meta analysis that seemed to add a little bit of confusion. Thank you for contextualizing those, this is by [inaudible 00:41:17] and [inaudible 00:41:18] Siri Torino. There's been some other ones that have come out recently, by Lora [inaudible 00:41:25] looking at butter. Is Butter Back was a title of their [inaudible 00:41:30] paper, or the very beginning of it. Now, obviously, we think of butter, we think of saturated fat, but it's got oleic acid in it, it's got different types of saturated fats, stearic, polymeric, et cetera. What about butter? What do you think about the work there, what's your conclusion, and how can you contextualize it in the saturated fat discussion?

David Katz - 00:00: One of the people who's contributed a lot to this dialogue, in the peer reviewed literature, is Dariush Mozaffarian who is the dean of nutrition at Tufts. I think when given the opportunity to say here's what I think it all means, Dariush has actually done a beautiful job, and he said, "All this talk about butter is back begs the question, compared to what?" If we mean compared to stick margarine, which, by the way, used to be loaded up with trans fat, absolutely. Butter's back and has been back for a long time. If we mean compared to olive oil? Extra virgin olive oil? Absolutely not. It's kind of a spectrum.

00:00: It looks as if there's a mix of saturated fats and dairy products, some of which still appear to be harmful, they're pro inflammatory, they're pro atherogenic which means they contribute to the plaque that gums up our coronary arteries, but they have other saturated fats that may offer some metabolic advantages, it's a bit of a mix. The net effect of eating butter, though, I'm aware of absolutely no literature, with the exception of one study in, believe it or not, dolphins, I'm aware of no literature showing health benefit from consuming butter, none. Despite all of the hype, when you clear the smoke out of the way, I can find nothing in the literature that says, "People who ate more butter had better health outcomes."

00:00: You routinely find exactly that conclusion regarding olive oil. You find exactly that conclusion regarding the fat that's intrinsic to nuts. Compared to what? The simple reality is, I don't eat any butter, Dan. I don't miss it, I don't like it, if I'm going to dunk my bread in anything, it's olive oil. I don't eat stick margarine, and if the choice for me were between stick margarine and butter, I'd choose butter, but I don't choose either. Why settle for "Not bad for you." Or "Not as bad for you as we thought." Or "Has a mix of fatty acids, some of which are bad for you and some of which are innocuous." Which is pretty much where we are.

00:00: There are other interesting foods related to the saturated fat composition. The predominant fatty acid in dark chocolate is a saturated fat called stearic acid and the literature is very convincing that stearic acid is innocuous. Beneficial? No. I'm not aware of any literature saying "Eat more stearic acid and it will make you healthier." It appears to be harmless, and then the net effect of eating dark chocolate is beneficial because it's a concentrated source of antioxidants called bioflavenoids. It's a concentrated source of magnesium and arginine which is a beneficial amino acid, and on and on it goes.

00:00: The other one that's really interesting is loric acid, which is the predominant saturated fat in coconut oil. Again, despite all the hype about coconut oil, just drink coconut oil and you can leap tall buildings in a single bound, bologna. I see no evidence in the literature of clear health benefit from coconut oil, but it looks likely that loric acid is also innocuous. You sit through all of this, you say, "Okay, very, very clear that saturated fats are not all created equal, and some don't do harm, and some probably do, and some may even offer a trade off of harms and benefits."

00:00: Still, the people who live the longest, have the best health, have the least chronic disease, do they eat diets high in saturated fat? They do not. The fats most consistently associated with health benefit are monounsaturated fats like the oleic acid that predominates in olive oil, and a balance of polyunsaturated fats found in the usual suspects, olive oil, avocado, nuts, seeds, fish, seafood. At the end of all of this, Dan, I think the best way to clear through the clutter, is basically take a page from [inaudible 00:45:39] playbook, and [inaudible 00:45:40] said, "Eat food, not too much, mostly plants." The rest of that 13,000 word essay in the New York Times magazine back in 2008 was mostly an argument against fixating on nutrients, and an argument for thinking about food.

00:00: I really preach that gospel more and more and say, "Look, you want to get your fats right, get your foods right." If you're mostly getting your fats, and I do this, personally, from nuts, and seeds, and nut butter and avocado and olive oil and other healthy cooking oils and fish and seafood. If you want to occasionally have coconut, fine, and you want to have some dark chocolate, absolutely, fine. If you want a bit of butter in your diet from time to time, but if mostly the fat in your diet comes from nuts and seeds and avocado and olive oil and fish and seafood, all will be well, because those are wholesome foods associated with better health outcomes, and surprise, the fatty acid composition of those foods is a balanced, healthy array of fatty acids associated with good health outcomes. Get the foods right, the nutrients will take care of themselves. That really should be the new age mantra.

Dan Pardi - 00:00: How often do we, if you're going to be making a comparison, I love butter, let's say. You get to have olive oil, which is amazing, too. You're comparing one great thing versus another, for me, it's an easy shift. If I have butter occasionally, the majority of my diet is from oleic acid sources, particularly, cold pressed olive oil. I don't know if you've seen, it's kind of a smaller study, but it's interesting to look at replacement studies of saturated fatty acids with olive oil. They had cream in a shake and they replaced it with olive oil and people lost about five pounds in a month just by replacing the oil type in an isocaloric diet.

David Katz - 00:00: Right, really important, and then there was a huge study by [inaudible 00:47:32] out of Harvard that answered the question the two meta analysis we've been talking about up until now, failed to address, which is when people reduce their saturated fat intake, what replaces it? What that study found in a hundred and thirty thousand people, followed for decades, was that if they replaced saturated fat calories with unsaturated fat calories from nuts, seeds, olive oil, avocado, et cetera, rates of heart disease and [inaudible 00:47:59] mortality went down dramatically.

Dan Pardi - 00:00: [inaudible 00:48:02]

David Katz - 00:00: Actually there have been other studies that have reaffirmed this, again, we're saying the same thing, Dan, that the message about the food pattern is clear enough, but I think you raise another key point in the final minutes here and that is, you can learn to love food that loves you back. My wife has a beautiful, free recipe site,, it's like cuisine city but with an I in the middle,, it's all the Katz family greatest hits and you can help yourself for free there, but the tagline is, "Love the food that loves you back." The way to get there from here, so you're saying, "Butter is great, but so is olive oil." If you think butter is great, but you don't think really fragrant extra virgin olive oil is great, it's probably just because you're not used to eating it.

00:00: Taste buds learn to love the foods they're with. One of the ways to improve your diet sustainably is to actually trade up within categories and give yourself a little bit of time to habituate. The new is always a bit of a challenge, but it just takes a couple weeks to start saying, "Yeah, this is pretty good and I can get used to this." You're a few weeks in and you can't remember what the fuss was about, and then you're a few months in and it's just a new way of normal. You can do that in every food category and trade up and make little shifts. I call that taste bud rehab, because frankly, taste buds in the US are so acclimated to a diet that is loaded up with sugar, salt, and food chemicals. That tastes normal. What it really means is your taste buds are in a sugar and salt induced coma.

Dan Pardi - 00:00: They're desensitized, yeah.

David Katz - 00:00: If you rehab them so that they become sensitive to sugar and salt, you need much, much less to be fully satisfied, and you can spend the rest of your life literally loving food that loves you back by supporting your health and vitality. The reason to do that, also, I think, gets too little mention. It's not because a doctor like me wags an admonishing finger and says you should, I think all too often health takes on moral overtones. The reason is, healthy people have more fun. The reason to invest in your health is not because anyone else says you should, but because if you've got health, you'll spend more of your life doing the things that you want to do, it's just a simple fact. The good news is, you can derive pleasure from food that's good and from health that's good, as opposed to paying for one with the other. I think it's a luminous opportunity all too many people are missing out on.

Dan Pardi - 00:00: Life and years.

David Katz - 00:00: Add years to lives, life to years, exactly.

Dan Pardi - 00:00: That's a great one. This is fantastic, thank you so much for taking the time to come and chat with us about a general perspective about health, which is so needed and then also to drill down a little bit into dietary fats and to discuss some of these confusing, seemingly, meta analysis that have spawned a lot of writing about how, "Hey, these things are actually good for us and you should change your [inaudible 00:51:01]. Don't listen to the experts." [inaudible 00:51:03] what the reality is and hopefully all the listeners will take that to heart. I really appreciate your time today.

David Katz - 00:00: Likewise Dan, it's been a pleasure. I'll look forward to our next conversation.

Dan Pardi - 00:00: Can't wait to have you back on, thanks so much.

David Katz - 00:00: Thank you.

Dan Pardi - 00:00: Bye bye.