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The Melanie Avalon Podcast Episode #61 - Dr. Cate Shanahan 

Dr. Cate Shanahan's training is in Family Medicine and her background is biochemistry and genetics, having studied at Cornell. She has authored three books including Deep Nutrition: Why Your Genes Need Traditional Food and THE FATBURN FIX, with MacMillan, released in March 2020. In 2011 Dr. Cate created a nutrition program for the LA Lakers that many NBA and professional sports teams have emulated. This program, along with the 2008 edition of Deep Nutrition are credited with helping spark the current bone-broth and collagen craze, as well as inspiring thought leaders in the nutrition and keto space.

Dr. Shanahan has served as independent advisor or consultant to dozens of companies and organizations throughout the world including the LA Lakers, OKC Thunder, Villanova Basketball, beliv - CBC Beverages, & Natural Stacks.  She has been featured in The Magic Pill documentary and The Real Skinny on Fat docu-series, Real Time with Bill Maher, Good Morning America, Scientific American, Sports Illustrated, Men's Journal, CNN, US News and World Report, Prevention Magazine, Vogue, National Geographic, GQ, the New York Post, Woman's World, People Magazine among others as well as numerous radio talk shows and popular podcasts.




1:35 -  IF Biohackers: Intermittent Fasting + Real Foods + Life: Join Melanie's Facebook Group For A Weekly Episode GIVEAWAY, And To Discuss And Learn About All Things Biohacking! All Conversations Welcome!

1:50 - Vagus Nerve Treatment: Get Xen By Neuvana: At Melanieavalon.com/Xen With The Code Melanie20 For 20% Off!

5:45 - Cate's Story

9:15 - Corrupted medical practices 

10:00 - The problems with insulin for type 2 diabetes

10:45 - Rethinking Saturated fat 

12:10 - When we went low fat 

16:05 - PUFAs, Oxygen Reactions, And Damage To The Mitochondria 

21:30 - How You Feel the Cellular Emergency 

23:00 - The Need For Snacking 

24:15 - Energy Generation Potential From Different Dietary Fats 

24:50 - Why PUFAs "seem" Healthy: Current Agriculture, Hiring Scientists, Rodent Studies 

30:05 - Lumen Lovers: Biohack Your Carb And Fat Burning (With Melanie Avalon)Join Melanie's Facebook Group If You're Interested In The Lumen Breath Analyzer, Which Tells Your Body If You're Burning Carbs Or Fat! You Can Learn More In Melanie's Episode With The Founder (The Melanie Avalon Podcast Episode #43 - Daniel Tal) And Get $25 Off A Lumen Device At Melanieavalon.com/lumen with the coupon code melanieavalon25

31:15 - How Long Are PUFAs Stored In The Body?

33:45 - Soy In Infant Formulas 

34:00 - PUFA Storage In The Cells 

34:50 - The Change In PUFA Body Fat Percentages

36:45 - High Carb Vs High PUFA Diet, And Becoming Carb Addicts 

38:30 -  Ray Peat And PUFAs 

38:50 - How Does Fat Cell Turnover Occur?  How iS Fat Burned?  How Blood Flow Affects Fat Burn 

40:00 - Fat, Blood Flow, And Lumpy Or Stubborn Fat 

43:40 - When It's Appropriate To Do IF

44:45 - Losing Weight When Metabolically Damaged, Rapid Weight Loss, And Weight Regain 

47:55 - BEAUTYCOUNTER: Non-Toxic Beauty Products Tested For Heavy Metals, Which Support Skin Health And Look Amazing! Shop At Beautycounter.Com/MelanieAvalon For Something Magical! For Exclusive Offers And Discounts, And More On The Science Of Skincare, Get On Melanie's Private Beauty Counter Email List At MelanieAvalon.Com/CleanBeauty! Find Your Perfect Beautycounter Products With Melanie's Quiz: Melanieavalon.Com/Beautycounterquiz

49:50 - The Brain, Pancreas, Liver Connection 

52:00 - Gluconeogenesis and Diabetes Type 2 Diabetes And Insulin Resistance In The Liver

55:05 - Elevated Blood Sugar On Low Carb Diets 

56:25 - The Vagus Nerve 

The Melanie Avalon Podcast Episode #58 - Ami Brannon (Xen By Neuvanna)

56:45 - Should You Take Fish Oil?

Deep Nutrition: Why Your Genes Need Traditional Food

The Fatburn Fix: Boost Energy, End Hunger, and Lose Weight by Using Body Fat for Fuel


Melanie Avalon: Hi friends, welcome back to the show. So, I am so, so excited. So, thrilled about the conversation I'm about to have. It is about a topic that my listeners, you guys know I'm like weirdly obsessed with. I've been talking about this topic a lot for probably the past year or so because I think it is something that is so important in our health today, our diet, our fitness, our metabolic state, and I just don't think it's quite appreciated or fleshed out or explored as much as it potentially should be. And I've been dying to do an episode on it.

And it just so happens that the author of a book that I read, probably about three years ago, that was a book called Deep Nutrition: Why Your Genes Need Traditional Food, I read that book when she released the rerelease in 2017. It was incredible. You guys have probably heard me talk about it, because I talked about it a lot on the Intermittent Fasting Podcast. I've been dying to have her on actually for that book. But then, she released a new book, which is called the The Fatburn Fix: Boost Energy, End Hunger, and Lose Weight by Using Body Fat for Fuel. And it taps into that topic that I hinted at just a second ago. And that's the role of polyunsaturated fats, vegetable oils, and all of that in our health today. So, excited to dive in deep.

Let me introduce today's guest. I am here with Dr. Cate Shanahan. She is trained in family medicine, and she also has a background in biochemistry and genetics, which, if you've read her books, that makes so much sense, because her books are so nuanced, so in depth. There's a lot of information there. So, I can clearly tell that that's her background.

But she's done so many things. She created a nutrition program for the LA Lakers that they use. She's worked with a ton of other companies. You've probably seen her because she's been all over the place. She's in The Magic Pill documentary, The Real Skinny on Fat docuseries. She's been on Good Morning America, Scientific American, CNN, Men's Journal, Sports Illustrated, basically just all the places and for good reason. It is my utmost honor to be here today with you, Cate, thank you so much for being here.

Catherine Shanahan, M.D. Thanks, Melanie. I'm excited to get introduced to your audience. I really appreciate that. Thank you.

Melanie Avalon: No, of course. I’m so excited right now. So many things that we could dive deep into, but before we do, to start things off, would you like to just tell listeners a little bit about your own personal story, what led you to your interest in nutrition and health and genetics, most recently with your book, The Fatburn Fix, what led you to all of that?

Catherine Shanahan, M.D. After medical school and a family medicine residency, I had gone to medical school in hopes of understanding underlying causes of stuff, specifically meant my own selfish desire to not be injured all the time when I tried to do any kind of sport-- well, not really like coordination sports, but just endurance sports. I was a huge runner in high school and college, but I was getting injured all the time. And my main goal in going to medical school was to be a sports medicine doctor and get to the underlying causes of stuff. But quickly, I learned that we don't get there, that medical science wasn't really focused on that. And there were just no answers. So instead of doing sports medicine, I did family medicine, because I thought at least at that point, we're still in that detective mode. That’s what I really love about practicing, is that being that person who really listens to my patients to get to the real origin of what their issue is, because even if people have headaches or heartburn something might sound like kind of cookie cutter treatment, throw a pill at it, there's always nuances that even before I understand the thing about inflammation, nutrition, I still felt like, “Well, there's a way to figure out which medication is going to help better than others,” or what kind of exercise might help or stress. I was always about underlying causes. My own health took a turn for the worse and I had a reawakening of my excitement, enthusiasm for biochemistry of fatty acids. I know it sounds really kind of weird, but--

Melanie Avalon: No, I love that so much. Sorry. I just had to jump in, I love hearing that. Sorry, continue.

Catherine Shanahan, M.D. I couldn't walk, that's how bad my health was. I had a viral infection probably-- we never really discovered the cause, but a viral infection in my knee that my body wasn't able to handle or eradicate because my immune system was so overloaded with inflammation that came up largely-- I was to discover the PUFAs in our diet and a huge amount of nutritional deficits because my diet was nowhere near like a human diet, like what I describe in Deep Nutrition.

I did ultimately get better, but in the course of revisiting my biochemistry books in 2002, essentially what I learned was that I been intentionally-- I don't know intentionally, but I had been lied to about saturated fat during all of my medical training. And it wasn't obviously just me, it's not like I went to a uniquely horrible medical school. It was all dieticians and nurses and every other doctor, every other specialist, the normal list of specialists like your cardiologists. They were lied to about saturated fat. Endocrinologists, who the people that treat diabetes. Neurologists, those people who treat stroke victims. Oncologists, who treat people with cancer.

This lie about saturated fat had so permeated every aspect of modern medical practice. It corrupted the way that we practice medicine, actually. And it corrupted our thinking, and so that our standards of care are just inadequate in ways that I still to this very day find shocking, because they mean that our some of the most common medical practices are just plain wrong and harmful.

So, just to give a few specific examples. The lie about saturated fat is the reason that cardiologists treat their heart attack victims with stents and surgeries, and those are not necessary once you recognize that saturated fat is not harmful, can actually give people real dietary advice. Stents and surgeries, these are painful, dangerous things that make lots of money for the medical system and drain people of their resources. In the case of stents, you have to take a blood thinner for life afterwards. That’s just one example.

Another one is, endocrinologists, the people who supposedly specialize in treating type 2 diabetes, they commonly use insulin for type 2 diabetes, which if you know anything about type 2 diabetes, you've heard this term before, 'insulin resistant.' That's the underlying cause of type 2 diabetes. So, if you're giving people who are insulin resistant just boatloads of insulin, that doesn't really seem like you're getting at a cure. And if you know anything about what insulin does, it makes you gain weight and get hungry.

I could go on. I could literally go on all day about the way that this lie about saturated fat impacted my own practice, and I still see impacting every patient who's like, I have to say, a victim of the healthcare system. If they have a chronic disease, you can go in and get out with a lot of good things having happened to you. If you, for instance, have a pneumonia or you need your appendix taken out. But you can get in, but you can't get out if you are still trapped in this world where saturated fat is bad. Therefore, polyunsaturated fatty acids are good, and you just cannot literally get enough of them. There's no normally trained doctor that's going to tell you that you shouldn't eat less saturated fat and more polyunsaturated fat. They're going to tell you you're eating too much saturated fat without ever asking you what you're eating, and tell you to make sure to eat canola oil and soy oil, without again ever asking you what you're doing and without a hesitation.

Melanie Avalon: It's so shocking and so pervasive. Just the other day, actually, my mom, I guess her cholesterol levels were less than ideal and she has one of the genetic tendencies towards having cholesterol issues. I was really happy because she was saying that she wanted to try to approach it through diet rather than pharmaceuticals, which is fantastic. But then, she was like, so I'm doing like a lot of like canola oil and all this stuff. I was like, “Oh, no. Oh, no. Mom, mom, listen to this episode."

To everything that you just said, one of the things that I didn't realize until I read about the Fatburn Fix was you pointed out that when the messaging started to be delivered to us that we should cut saturated fat and go low fat, that we actually didn't change the amount of fat we were eating, and I didn't realize that. I thought that we did go lower fat, but then we also went higher carb. Would you like to talk a little bit about the switch that happened there?

Catherine Shanahan, M.D. Yeah. If you look at the statistics, the government is pretty good at collecting statistics on how much of these macros people are consuming. You can see-- It tracked back, starting in 1909, but a lot more detail from 1960-1970 timeframe. And you can see that what happened in the 1980s with the campaign around going low fat, and especially specifically going low fat, the fat intake at that point in time was fairly flat line, but a lot of it started actually to increase. We started eating a little bit more total fat. We did eat also a significant more amount of refined carbs and sugars.

But really the big, huge change, way more than the basic fat versus carb argument is the types of fat. We did start eating way less saturated fat, and way more polyunsaturated fat. And I have a graph of this in Fatburn Fix and also on my website that shows that our consumption of the saturated fat-rich foods like butter and lard has really been not changed much since 1970, 1980. Lard went down, I guess, between '70 and '80, but hasn't really changed much since then. It hasn't really changed that much since the turn of the century. They each clock in around 10 pounds per person per year, butter and lard. In '60s and '70s, it went down to five and now it's somewhere at four and two respectively. It's not a huge change.

But what was a huge change is the seed oils, the soy, sunflower, safflower, corn, cottonseed, canola, there's two more, so that equals eight. So, I call them The Hateful Eight. And that consumption was nil because these are at the turn of the century, I mean in 1909, it was nil, it was a pound or two per year because these are industrially produced. So, they simply didn't exist. So, they were nil. Now, is somewhere around 100 pounds per person per year. We’re eating massive, massive amounts of them.

When you look at the big picture of our total fat consumption, it has gone up a little bit as has our carb consumption a little bit. But it's really the details of the fat type itself that is just the absolute key that no one is paying attention to, because the difference between the seed oils that we are now consuming at unprecedented rates and the traditional fat is the fact that the seed oils are high in PUFA, polyunsaturated fatty acid, which is unstable, reacts with oxygen in our bloodstream, causes inflammation and drains our bodies of energy. When we try to burn it for fuel, we actually produce inflammation. And as a protective measure, we end up developing diabetes. And that's what The Fatburn Fix is about. It's a revolutionary way of looking at the big picture of human health and understanding where type 2 diabetes really originates, is not in the overconsumption of carb. It's in the overconsumption of inflammatory PUFAs that disrupt our basic biology and cause pretty much all metabolic disease. And one of the end stages of metabolic disease is type 2 diabetes.

Melanie Avalon: Yeah, I just find this so fascinating. I keep mentioning the other show, the Intermittent Fasting podcast, but ever since I started tapping into this and learning more about how these polyunsaturated fats are burned in our body and how they affect ourselves, how they affect our metabolism, because people will write into us on that show all the time about not being able to lose weight or feeling they're stalled or feeling they're plateaued. Historically, we would talk more about addressing the fasting or addressing the macros as far as low carb or low fat. But now, I always just have to throw in there like, if you haven't tried cutting out PUFAs, just give it a go.

To paint a picture though of actually what is going on-- First of all, like I said, I am so obsessed with the idea that you study the metabolism of fatty acids. I love that. I think I could just study that all day. But, yeah, what actually is going on there? The different types of fat, saturated fat, monounsaturated fat, polyunsaturated fat, literally on a biological, physiological level, what's happening when we burn those? You do go into detail in the Fatburn Fix about the carbons and the enzymes that are used, but why is burning saturated fat potentially actually supportive of our health and metabolism, and these PUFAs are not?

Catherine Shanahan, M.D. Right. It's a super important question. Why is saturated fat better? Why are PUFAs so bad? The simple explanation is that the PUFAs are unstable, and they react with oxygen. When they do that-- the way that we actually generate energy, I’m sure your listeners know this, but I want to put it in the context of this discussion. We generate energy using oxygen. All the calories you've ever burned, have been burned inside these little mitochondria, which are little chambers in your cells that use the oxygen converted to cellular energy called ATP or adenosine triphosphate. Without mitochondria, your cells would die. We would not be able to generate energy, and we wouldn't use oxygen. Some very primitive types of bacteria, they don't have mitochondria, they don't need oxygen. But we do.

I did earlier say PUFAs are unstable, they react with oxygen. What that means is, things aren't going to go well inside the mitochondria, where there's a lot of oxygen and a lot of PUFA. When your diet has been full of PUFA-- and right now, the average person consumes about 80% of their total fat calories from PUFA. This average person also has somewhere around 40% of their total daily calories coming from fat. So, it's hundreds and hundreds of calories from PUFAs.

Those PUFAs are then going to be delivered in a reasonably high concentration, a fairly dangerously high concentration throughout your bloodstream to your mitochondria, where they're going to get reacted with oxygen in a way that nature never intended for these two things to come together in high concentration. And it's bad when that happens, because we can't control the reactions, our cells are not designed to have to deal with this issue. It's like if you put some kind of-- your car needs gasoline-- or maybe a camp stove would be a better analogy. You have a camping stove, and you have that little propane fuel tank hooked up, and it's designed to work with that particular camp stove. You get a perfect little stream of a blue flame because there's a certain fuel that goes with that camp stove, certain different varieties of fuels. If you try to get that camp stove to burn candle wax, for example, it won't work. On the other hand, if you try to get it to burn, like jet fuel, it might explode.

So, it's the way our cells are tooled. But there is really not a lot of organisms, of higher organisms, like humans or mammals that are tools to handle this much PUFA. Our mitochondria just can't handle it, and it damages them. And instead of producing energy, they produce heat and inflammation. You get this stuff called free radical cascades, which is a chemical chaos inside the mitochondria in an attempt to protect themselves from being totally destroyed because free radicals are like bullets ricocheting around inside the poor mitochondria, ripping apart their membrane and ripping apart all the little bio machines in there that we call enzymes that do the work of the mitochondria. To protect itself, there's actually a fuse in the mitochondria, like you have a circuit breaker in your house. When that fuse gets pulled in the mitochondria, energy production in that mitochondria shuts down. You do that in all the mitochondria in a given cell, and the cell is going to die in six seconds, because it needs constant energy. Whatever amount of energy it normally produces, if it doesn't get that for more than just a few seconds, it starts to die, it starts to swell, and everything starts to work incorrectly. So, we have an emergency. We've created all these little cellular emergencies.

This isn't just something that I'm talking about that I could draw it on a chalkboard with all kinds of cool little diagrams and stuff. You actually feel this when happens. If you ever experienced being hangry or having brain fog when you're hungry, and feeling better when you eat something, that's a reflection of the fact that your cells were not producing energy, somewhere probably in your nervous system or your gastrointestinal system. That's where we develop all these kinds of, I call them “hypoglycemia symptoms,” like you are not getting enough energy. It literally means low blood sugar, but really, it's low energy. If you've ever experienced that, that's most likely because like I was, like most of my patients, were unknowingly just consuming massive gobs of these PUFAs, high-PUFA seed oils, and having no clue of how it affected me or even that I was doing it. I didn't even know what seed oils were. I didn't know what canola oil was until I started cracking open the biochemistry books and looking at the labels to try and understand how much of what I was eating.

So, it is very empowering to have this connection, when I make this connection for my patients that they understand, “Oh, okay. Well, there's a reason I feel this, it's not just that I need to snack," because as much as people love their snacks, those snacks are usually what's going to make it very difficult for you to lose weight. If you are driven to snack every few hours and you want to lose weight, that's not a good combination. It's not going to be very easy to lose weight. You have to do something about that drive, that hanger and the brain fog and the anxiety and the things that happen when you feel like It's been too long since you ate. It hasn't been too long since you ate. It's been too long since your cells got energy. And there's a way to get out of that without eating more calories in any given day. And that's the whole plan in The Fatburn Fix is there to teach people to do, is how do you build a meal that's going to sustain your energy so you don't have to eat an unhealthy amount of calories.

Melanie Avalon: This is just so fascinating. I have so many follow-up questions. Oh, my goodness. Basically, when we take in polyunsaturated fats, they're not meant to be a fuel for energy per se and instead they just create oxidative stress, heat. And then like you said, it's like a circuit breaker and then the cell just shuts down. You talked about in your book that there was a study where they actually looked at the-- I guess the energy generation potential of like monounsaturated versus the different polyunsaturated versus saturated and it was literally the cells glowing, like if they were creating energy or not. And the monounsaturated fats made the cells glow, like at 115%. But the polyunsaturated made it literally dim, like 20% to 50%. It’s just really fascinating. So, a question about that. There's often this idea, though, that it's harder to gain weight from polyunsaturated fats. I don't know if that is because it ties into all of this because they're not supposed to be burned as fuel. Where did that whole mythology come in, that we should actually be eating these for weight loss?

Catherine Shanahan, M.D. They try to use the concept that these are good oils in everything. So, whatever you've heard, it's not based in valid science. It's based in some kind of gobbledygook version of science. They've said that these polyunsaturated fatty acids help people lose belly fat. They've said that they help people-- they clear up their skin. We have to not put the blinders on, but the BS alarm should be sounding really loud anytime you hear people talking about the seed oils as a good thing, because the big picture is this simple. We grow corn and soy, and we grow gallons and gallons and gallons, billions of gallons a year worth of the oils from corn and soy, because these two plants can grow in just about any climate, and they can grow in almost the entire middle of the country.

When you fly from New York to LA, and you look down over Montana and Iowa and Nebraska, you see these green squares and circles. That isn't broccoli, folks. It's not kale. It's corn or soy most likely. There's a couple of things, and it might be wheat. But the fact is those are high in PUFAs and we, not me, but the powers that we have to sell these products that are high in PUFAs, now, because that's what we grow, it's what the company's own. And in order to do that, they just hire scientists. The nutrition world, the nutrition departments at Tufts and Harvard and Stanford and Yale are marketing arms of Conagra and Dow and Kraft and Tyson and all the big food guys out there that have so much money. This is the biggest industries. The agribusiness is one of the biggest industries in the United States. They control the information stream.

And if you really want to understand what you're reading with nutrition science, you have to be an expert in statistics, you have to be an expert in animal physiology and comparative anatomy because they're talking about mice, but we're humans. You have to be an expert in genetics because you have to understand that years of breeding mice to eat survive on lab chow has drastically altered everything. All the results that you're going to see on mice and any lab animal, you have to understand, of course, the biochemistry. You have to know so much to not be boondoggled by this huge infrastructure that's there to boondoggle you. That's how doctors buy the lie, that saturated fat is bad. It's not that we're disinterested or ignorant. Well, it’s not like we're willfully ignorant. We are sold a very complicated series of lies, one after the other that pile on each other, starting in at age five, when we start reading cereal boxes, and we're just told that Cheerios is healthy because it lowers your cholesterol. To answer the specifics of your question, I would actually have to see the particular study to know, “Okay, here's how they gamed the system in this particular way on this particular time,” and you can spend your life having fun with that, like, “Oh, this is what they did.”

Well, what they did was they deprived animals of all PUFAs. And then, they gave them some, because here's the thing, here's the cincher. This is how doctors get fooled about PUFAs. We do need some. We can't make them. We do need some in our diet, and we need them in our body. But the amount that we get is toxic. So, that's the problem. The fact that we do need some means there's so many ways that now you can trick people who won't chase the long tail of references, so you don't know what is actually happening and the details of a study, if they say that, “Oh, PUFAs are good” in the summary, you have to look at all the materials and methods to know what they were actually comparing. Were they comparing some PUFAs to more PUFAs? Or were they comparing no PUFAs to some PUFAs, you know what I mean? You have to do so much legwork to really understand what any given study is actually studying, because they're not honest about that. They're not forthright about that. They hide it.

Melanie Avalon: Yeah, 100%. I've definitely seen that myself looking through a lot of the literature as well. And while we're in the dark dismalness of all of this, I have another dark dismal question, but I will say for listeners, if you get the Fatburn Fix, everything is okay. There's a way out. There's a plan. So, definitely get it while we're on the dark dismal side of things. When we eat PUFAs, obviously, there's that initial problem of burning it, and it being inflammatory and oxidative stress and all these problems. But what is the significance of PUFAs not just being burnt in that moment in the mitochondria, but then the implications of storing them in our body when we do store fat and the half-life of these in our cells? When we've been consuming these PUFAs for a while, what happens to the makeup of our cells and how long does it take to fix things? Because people might think, “Oh, okay, I just won't eat any more PUFAs, I'll be fine.” But is there a lot more undoing that has to be undone first, because of the PUFAs built up in our system?

Catherine Shanahan, M.D. Yes, but the good news is that the very first day that you stop eating them and start eating healthier fats, you're training your cells to lose their fear of fat, to lose their addiction, which is your addiction to sugar, and to start turning your metabolism around from the road it was on, which is a road that ends in disability and death, just while we're being grim and dark. Let's just lay out the end product here. So, that's where people are going. That's the road I was on. But I mean, the thing is as bad as it sounds, it means that if these things are so bad, it means that getting them out is so good, right?

But to get your question of how does that really play out if you've been eating for decades. So, let me just start from birth. When we're born, we have a relatively normal constitution of fatty acids in our body because it's regulated. The body is a control freak, and it tries to build the building blocks in the right way. What happens after we're born is that when we have way too many PUFAs in our diet, even which-- a lot of infant formulas are soy oil, corn oil, it's canola oil. So, it's horrible that we wean children on this or we give children this the first day of life and we start getting their body fat just loaded with PUFAs from day one. But it is their body fat, that's where it concentrates the most, because our cells, every individual cell is surrounded by a membrane that's made out of fat, but that membrane has to have a certain consistency or the cell won't survive. So, it's very regulated.

There's limits to how much additional PUFA can end up in a given cell and can end up in most tissues. It's only going to be the storage where if a cell stores any extra fat, it's going to be PUFA. And of course, the cells that do that the most are the fat cells, that's their big job. The place that these PUFAs end up affecting the heaviest is our adipose tissue. That's the fancy word for the fat under your skin. When we were born, the amount of PUFA on our body fat is supposed to be somewhere around 2% to 4%, we think. It's been so long since we've had a normal human diet that you have to go back to the 1920s.

Melanie Avalon: Wow.

Catherine Shanahan, M.D. Yeah, and even then, we had a little more PUFA than probably we did all throughout most of human evolution. But back at that point in time, it's unknown how accurate the assays were that assessed the amount of PUFA because it's so unstable. So, anyway, but it looks like it's somewhere around actually 1% to 2% in the study. So, I'm kind of doubling it when I say 4%. That was then. What is the percentage now? It's like 20% to 30%. So, it's 10 times, 10X the amount of PUFA. And that is an incredibly unusual thing for an animal to have to survive, and it makes us just unhealthy. As soon as it builds up to these thresholds where even our body fat itself is now just a source of PUFA as much as a French fry would be, that's where things really start to go haywire. And that's going to happen at a different age depending on your diet and your genetics, because everybody has some ability to handle a little bit of extra PUFA-induced inflammation. And everybody has some ability to try to clear it out of their body. But different people have different amounts. So, for one person, the amount of PUFA, where they're going to suddenly start to feel bad might be like 10% or 15%. For another person, it might be 20%.

But there's coping mechanisms along the way that lead to things like obesity. For example, if you feel bad when you tried to burn your body fat, and your body decides to protect itself by just making you really hungry instead of trying even to burn that body fat at all, and you eat, say, a high-carb diet. A high-carb diet is actually healthier than a high-PUFA diet because when you eat too much carb, what happens is your body turns the extra glucose molecules into saturated fat molecules mostly, saturated and monounsaturated. I'm sure your listeners know that when you eat too much carb, you store the extra as fat. And that's a normal process, the body can handle that, but some people adapt to this high-PUFA diet by becoming really good at that, and also by essentially becoming carb addicts, because at least the sugar and flour isn't loaded with PUFA. And the sugar and flour can be converted into a fat that our cells can use, either monounsaturated, or saturated fat. So, getting overweight and developing diabetes and terrific carb cravings is actually an adaptation to this high-PUFA diet that some people have.

Some people they blame themselves or they blame their genetics. “Well, everybody in my family is overweight, it's just in my family.” That's not true. That's what happens to your family on a high-PUFA diet. Whereas the next family, they may all maintain normal weight. But as they get older, they develop some other problem. And you don't know what it is, but it's something. It could be, for example, autoimmune disorders or digestive problems or cancers. So, that's why different things tend to run in people's families. But it's all coming from the same root cause, it's all metabolic disease. The problem with the metabolism is that it's not producing energy, because there's just way too much PUFA in the diet.

Melanie Avalon: Yeah, this is so fascinating. I've been following the work of Ray Peat for a long time, which is one of the reasons I'm all into the PUFA stuff. But one of the things they talked about in that community a lot is people who do actually a low-fat, high-carb version of his diet that at least the body generates the correct fatty acid profile from the low-fat, high-carb diet.

I have a super random question. Fat cell turnover, because like I said, I've been sort of haunted by this idea of PUFA depletion for a long time. I'm like, “Oh, I want to be PUFA depleted.” Our fat cells, are they necessarily always turning over, even if we're gaining weight? What I mean by that is, say that a person-- presumably, if you lose weight and burn that fat that, then that fats gone. But let's say that a person has body fat that is unfavorably high in a PUFA ratio and then they either just change out the fats that they're eating, so maybe they just maintain their weight. I'm assuming if that was the case, that eventually the cells would cycle out. But even if a person was gaining weight, but they were now gaining weight from-- I don't know if this is possible, but took in no PUFAs, would they still cycle out that old toxic fat and would it be replaced with noninflammatory fat even if they're still gaining weight? Or can fat just sit in our body forever, and never be touched?

Catherine Shanahan, M.D. The answer depends on understanding how fat works. The answer is both actually. In some cells where there's not a lot of blood flow, the fats going to sit there for a long time. And in other cells, where there's more blood flow, that fat is going to be offered up into the bloodstream to be offered then up to the cells to potentially burn when you are going long enough without eating. When your insulin level drops, you have to have a certain amount of stimuli to get the fat cells to release their fatty acids that they're storing. They may each-- like any given fat cell may release a certain amount, or it might be like a few fat cells that release more than others, and that's just going to depend on the blood flow. The more weight that you have, the more difference there is in the blood flow in one area versus another. So, there's areas that won't be getting a lot of blood flow. And then that's where we get some lumpy fat happening, where the fat builds up more there. The areas where the fat cells get more blood flow and can periodically release their fatty acids into the bloodstream, that's where there's almost like a little divot. So, there's more blood flow there. At least, this is the way I put it all together.

If you've ever felt somebody who has lumpy fat, that's a result of the difference in the blood flow and the cells that don't get too empty out very often are more tense and feel more hard. So, that's what forms the lumps. But if you want to know how long does it take, they've done studies on normal weight people, and the half-life of any given fatty acid in your fat cells is about 18 months.

Melanie Avalon: So upsetting. Well, a little bit. It's upsetting if you're not in the state you want to be at.

Catherine Shanahan, M.D. Right, exactly. Let's say that if you're 30% PUFA right now, if you just stopped eating them completely, for whatever reason they stopped storing up in your body fat, let's say, then, in 18 months, you would be presumably at half that level. So, 15%. Now, how long until you're totally clear? Well, they usually say like three to four half-lives, so that would be like maybe four years. But the fact is, the more often that you enter these states of releasing your body fat, the more turnover there is. So, you're going to have more time where, yes, you're building new fat from healthy fatty acids or carb. And then, you get to release just a random sampling of what's in your fat cells, which is going to include some of that PUFA. So, that's one of the reasons that I am a big fan of, certainly not snacking, but intermittent fasting even, even just skipping a meal, which kind of guarantees that for a certain portion of every single day, you're going to be releasing larger amounts of free fatty acids from your body fat, which gives you that turnover. So, that's the benefit of fasting, is you accelerate the turnover.

Even if you're not losing weight, you're just freeing the bad things and giving them a chance to be burned at hopefully a lower concentration where they won't damage your cells. So, the Fatburn Fix, I help people understand that the plan is going to accommodate for all this. It's going to give you the opportunity to get your hormones to the place where you can release free fatty acids. Because if people are type 2 diabetic, their body doesn't work properly in a lot of ways, and they may not be ready to intermittent fast. So, I get folks to understand that whether or not they are, it's a very important question to understand whether or not you're ready to intermittent fast. I teach people how to assess that. And if they're not, I teach them what to do. And I teach them how to tell when they are ready. I also teach them what to eat to get themselves to the point where their body can handle an amount of inflammation that's inevitable, but we have to deal with that just to get rid of the PUFA but to handle it better. You want to fortify your antioxidant enzymes, basically, is what part of the preparation process is. And all of this ties to-- the point of all of this is really, when you're metabolically damaged, weight loss should not be your first goal. If you're metabolically healthy and you're overweight, yeah, then your problem is you're overweight and weight loss can be your first goal. But if you're metabolically unhealthy and you're overweight, you have to become metabolically healthier first, before weight loss is going to be a good idea.

And that's a huge departure from, I think, what most people really want to hear honestly, because you don't want to hear that, “Yeah, I know, you want to lose weight, and you want to get fit and look better. And you want that now.” Well, the fact is that that model has failed. We've been trying with this model of rapid weight loss, “I just want to get 40 pounds off, and then I'll start eating healthier. I want to lose weight fast, and then I'll focus on my health.” That has proven to be a failure. We have done that and it always, almost always, leads to weight regain. It's to the extent that there are so few and far between the people who actually managed to keep weight off with that model of rapid weight loss first, like the Biggest Loser contest kind of scenario, there's so few people that they ask them to enroll themselves in a study. That's how rare it is that you can actually keep weight off for five years, if your primary focus is rapid weight loss and you forget about improving your metabolic health, it's just not even a question. They find that of those people who succeed, what they all seem to have in common is they make their diet their career.

If you're willing to turn your life totally upside down and become a fitness guru or a nutritionist or dietitian or something, then you can focus on rapid weight loss and not have to pay attention to the PUFAs. You're eventually going to be eating less because when you start cooking for yourself, that's what happens. You naturally do eat less and that is, I think, a common element to how all these folks ultimately get to succeed. Even if they didn't start out focusing on PUFAs, they end up avoiding them. That is a necessary element for long-term success.

The weight loss as a primary goal is an unhealthy way of approaching the problem of metabolic disease because we've got it backwards. It's not the weight that causes the metabolic disease. It's the metabolic disease that caused you to gain weight. Because you were overly hungry and underly energized, you are much more tired and much more reluctant to be that active person that's just going to naturally burn calories without even realizing that's what they're doing.

Melanie Avalon: I'm so glad you touched on that. And that was one of the things I really loved about The Fatburn Fix was, it's not one plan for everybody because there's different phases depending on where you're starting out with your metabolic health determines where you can jump in and where you can go with it. So, listeners, definitely get the book. I want to be super respectful of your time. There's like a million other things I could ask you. But there's one thing I did want you to touch on, if you still have like a moment. And it's just because it was a huge takeaway for me. I read it and literally immediately messaged my cohost of the Intermittent Fasting podcast, and I was like, “This is so brilliant. Why have I not read this before?” You talk about the feeling of hunger versus feelings of hypoglycemia, and this idea that the ironies of the hunger that we experience today, because most of us obviously have tons of fuel in our body to be fueled if we could use it, yet we experience this feeling of hunger, which literally is an energy crisis, because our cells literally are not getting energy. But the thing that you talked about was the difference between the signaling for energy between the brain, the pancreas, and the liver, and how there's mixed messages going on. Could you talk briefly about that? It just blew my mind, it was incredible.

Catherine Shanahan, M.D. What happens as a person goes from being healthy and having normal fasting blood sugars to having prediabetes and having elevated fasting blood sugars, is that their body is caught in this battle for energy, where the brain and the pancreas are fighting for control over the liver. What's going on is the brain says, “I've observed that because that's what I do, I observe things and I learn, I'm brain, I’m smart. I've observed that having this fasting blood sugar set point, that used to work of say, 70 to 85, as a fasting blood sugar set point, that doesn't work for me anymore. I'm running out of energy all the time. It really sucks, because I can't function without energy and I could die, and I can't reproduce other cells down there. You might be able to reproduce. Well, it really sucks for me up here, because once my neurons die, they're dead. So, I can't let that happen.”

So, the brain shoots a signal down to the liver to produce more sugar faster out of protein. That's how it does it. So, the brain sends a signal to the liver, "Start turning muscle into protein, I don't care where you got to get the protein from, but just start turning amino acids into sugar." The process is called gluconeogenesis. The very first sign of prediabetes is elevated fasting blood sugar level. When you're fasting blood sugar level is the number of 90, when you've had one that was 90, you need to get some follow-up testing done to see if you're prediabetic, I talk about the follow-up test in the book too. It doesn't necessarily mean you're pre diabetic, just because you have one reading, but it means you need some follow-up testing.

So, the pancreas, meanwhile, says, “Hold on here. I have all this sophisticated biological detection machinery and regulation machinery in the form of glucagon and a bazillion other hormones that are sensing blood sugar level. And I know that we still need it at between 65 and 85, or some of my cells are going to start to die," because sugar is toxic to pancreatic beta cells, which are the cells that produce insulin. And so, the pancreas desperately signals to the liver with insulin, “Come on. Get the sugar back down. I need it down lower, it's 95. And I can't handle that all night long, I need it to be 75,” or something like that. So, it starts producing insulin, and the insulin goes to the liver. And the liver, then if it was going to obey the pancreas, the liver stops producing sugar out of your muscles.

But that isn't how it ends up because the brain wins. The brain is the ace of spades in terms of controlling what the liver does, because of the way that our bodies are wired. The brain actually is hardwired with the vagus nerve, and that is a stronger impulse that is more impossible for the liver to just ignore and be resistant to than the insulin hormone signal. And so, that's why type 2 diabetes is associated with insulin resistance specifically in the liver, as well as a number of other organs. But that's how I believe it starts.

And so, yes, your brain is at war with your pancreas for control of the liver when you have type 2 diabetes, and that's just not going to feel good. [laughs] Not to make light of it, but it's really a serious derangement that just cutting carbs doesn't do enough to help. You have to get your brain to calm down about the blood sugar level being lower than it really wants. And the only most efficient way to do that is to give it some healthy fat-based fuel, which would be your saturated, monounsaturated fats, or ketones. And that's a whole other discussion, which we'll maybe you have on the keto podcast. [laughs]

Melanie Avalon: What about a lot of people on low-carb diets, are not perceiving or experiencing hunger, but they have chronically high blood sugar? I feel like I see that all the time, and people in the low-carb community.

Catherine Shanahan, M.D. Right, where they feel fine and their blood sugar's a little high?

Melanie Avalon: Yeah.

Catherine Shanahan, M.D. Well, it depends where they are in their metabolic recovery journey. But let's say they're healthy and their blood sugar's high-- I've seen that happen when people are really fit, and especially in men, and the blood sugar is not really, really high. It's just maybe like 100 or 110. And that tends to happen more in the morning because of cortisol. Your hormones are just telling your body to just, “Let's just flood this person with fuel because I know this person is going to be active. And I want to make sure they've got fuel of all kinds, including plenty of sugar.” And so, I don't think it's the same scenario as a person who is insulin resistant. It's very easy to tell. You just check an insulin level. You see if you're insulin resistant. You can do your HOMA-IR score. But there's also other tests that you can do that will tell you which scenario you're in, if it's a problem, or not.

Melanie Avalon: Perfect, gotcha. For listeners, there's a whole section on insulin resistance, on things to test on all of that. Definitely, like I said, get the book. I'm also glad you brought up the vagus nerve. Actually, the episode that came out while we're recording this yesterday was all about the vagus nerve. So, if listeners want to learn more about that, check out that episode. I want to be super respectful of your time. Two last very quick questions. One, I just have to ask because I can't tell you how many times I get asked this and I ponder it myself and I'm so on the fence. How do you feel about people supplementing fish oil, like omega-3s?

Catherine Shanahan, M.D. You don't need to if you stop the PUFAs, we have studies that show that without supplementing, you can double your blood omega-3 content without eating any more if you just stop the seed oils, because all of that oxidation damages what little omega-3 might be in your diet. And when you stop that oxidation, then there's enough omega-3 in a lot of people's diets where they're fine, you don't need to supplement. You have to remember that, we don't need that much. Maybe 1% of our calories, maybe should come from omega-3 And if we didn't already have tons of it onboard, another 1% from omega-6, because we do need both, and we can't convert them into each other and we can't manufacture either one. Walnuts and seeds and dairy fat have omega-3. And the healthier the food itself, especially the animals, the better they've been fed, the more omega-3 is going to be in the body fat in comparison to omega-6.

Melanie Avalon: Okay, awesome. So glad we talked about that, because people ask me this in my group, like, weekly. So now, I'm going to be like, “Check out this episode, we talked about it." That brings me to the last question that I ask every single guest on this podcast. And it's different topic a little bit. But it's just because I have come to realize with all this stuff, all the health stuff, just how important mindset is surrounding everything. And, oh, actually speaking of listeners, simply get the book because Cate does talk about the mindset. She talks about the role of habit formation. She talks about something really cool about how you can make yourself start craving different foods. There's just a lot of really cool tips and tricks in there. But so, for the last question, what is something that you're grateful for?

Catherine Shanahan, M.D. Oh. Well, I just lost my cat and I'm grateful that I had her for 10 years because she was the most amazing, amazing cat ever. We don't have kids, so we get overly attached to our pets. And she was a Maine Coon that we rescued 10 years ago. Just everything she did was adorable. Just the way she sat. She didn't sit sloppy. You might see a cat sitting and just isn't thinking about how she's sitting. She always looked like she was thinking about how she was sitting. She had her two front feet. When you sit up in that triangle like cats do, two front feet were together, and they were like facing outward. She was just adorable in every way. She was always paying attention to us and she just did everything like a person would. We tell her to come and she'd look at us like, “Are you serious? You really want to come? Is this going to be worth it?” And then, you'd say, “Come on, Polly, yes, it's going to worth it.” And she'd come at no matter what. [laughs]

Melanie Avalon: How big was she? I just googled Maine Coon. Was she really large?

Catherine Shanahan, M.D. She was super fluffy. But she was kind of petite for a Maine Coon, she was only like 9 to 10 pounds. A lot of Maine Coons, they get up to 18 pounds, and we had one at one point that was 20.

Melanie Avalon: Wow, what color was she?

Catherine Shanahan, M.D. She was like orange and brown like tabby colored and she had these beautiful green eyes, and she was just the sweetest thing. She just wanted everybody. She just always wanted to do the right thing. And if any of the other animals got out of line, she would correct them for us.

Melanie Avalon: Aww.

Catherine Shanahan, M.D. Yeah. She would go after them and [[unintelligible [00:54:29] them.

Melanie Avalon: Oh, my goodness.

Catherine Shanahan, M.D. Yeah, she was the most beautiful thing.

Melanie Avalon: Well, she obviously had a great family. I'm sorry to hear about that. But I'm glad that she was part of your life. I'm a cat person too, by the way.

Catherine Shanahan, M.D. Maine Coon are the best, if you haven't ever tried one.

Melanie Avalon: I don't have a cat right now. I was thinking of getting another one, but I'm sort of allergic. They probably shed. I was thinking of getting one of those ones that's like hair, but they don't have the dander or they don't shed. I don't know. My sister has one. They're called Siberian something.

Catherine Shanahan, M.D. They're related to Maine Coon if they're Siberians, yeah. The thing about the long hair cats is they don't shed as often. That's why their hair is longer. And so, a short-haired cat is going to be losing a lot more hair all the time.

Melanie Avalon: Maybe I'll have to look into Maine Coons. All right. Well, thank you so much, Cate. This has been absolutely, absolutely amazing. Again, for listeners, the show notes for today's episode will be at melanieavalon.com/fatburnfix. I'll put links to everything that we talked about there. There will be a full transcript. I've so many more things I could ask you. I'd love to bring you on again in the future if you're up for it. Do you have another book in the works?

Catherine Shanahan, M.D. I'm not sure, but I do have courses I think I'm going to be starting to release. It’s going to take a while, but I'm thinking of doing like an expert's level course or a consumer-level reverse-your-diabetes course or just to help support the information that's in the Fatburn Fix, something.

Melanie Avalon: Awesome. Are there any other links you'd like to put out there for listeners?

Catherine Shanahan, M.D. My website is the main one, drcate.com, D-R-C-A-T-E dotcom, because you can link to everything from there, Facebook, Twitter, Instagram.

Melanie Avalon: Perfect. All right. Well, enjoy your Saturday and hopefully we can talk again in the future.

Catherine Shanahan, M.D. Thank you, Melanie. This has been a lot of fun for me.

Melanie Avalon: Thank you. Bye

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