But Are You Thriving? Episode 9 Recap: Learning From Our Ancestors With Mark Sisson 

What happens to your body when you start to eat a paleo diet? What about your brain? 

Thrive Market co-founder Nick Greene sat down with Mark Sisson, founder of Primal Kitchen, author of The Primal Blueprint, and widely considered one of the founding fathers of the modern paleo diet, to learn about his personal journey with primal eating. In this honest conversation, they talk about SIsson’s early life as a distance runner and triathlete, his struggles with IBS, and how changing his approach to food helped to heal many of his health struggles — and continues to fuel the active lifestyle he maintains as he prepares to enter his 70s. 

Full transcription below. Subscribe, download, and listen to this and every episode on Apple Podcasts or Spotify.

But Are You Thriving? | Episode 9: Learning From Our Ancestors With Mark Sisson 

Nick Green: Hi everyone. I’m Nick Green, co-founder and CEO of Thrive Market and your co-host of the But Are You Thriving podcast where we explore what it means to thrive in our world today for our bodies, our minds, our families, communities, and planet. Our guest today, which I’m super excited about is Mark Sisson. Mark has been the defacto leader of the “primal living” or paleo movement for over 15 years and really got the whole thing started back in 2009, when his New York Times best selling book, The Primal Blueprint came out. It argued what was then a controversial hypothesis that human health is best served by eating the same foods that our ancestors did, the foods that our bodies are actually evolved to metabolize. It’s interesting Mark, since then, I feel like the medical community has started to catch up, though they’re probably still not where you were 15 years ago.

Mark also runs the massively popular blog and YouTube channel Mark’s Daily Apple, which has been the go-to entry point for millions of people into first the paleo movement and more recently the keto diet. I was actually one of those people back in 2010 when I first started dabbling in paleo and literally Mark’s books and his website were the only resources I used. There actually weren’t a lot of resources back at the time. Mark’s mission to make primal living mainstream has gone well beyond content. He’s also the founder of numerous companies, including Primal Nutrition and Primal Kitchen, and I hear he’s got another one in the works. Primal Kitchen, by the way, launched on Thrive Market in 2014 and was acquired in a major transaction three years ago by Kraft Heinz. And then finally, Mark has really given back to the community seating a lot of other health and wellness companies as an investor and an advisor.

I’ll also mention that Thrive Market is one of those businesses. And a lot of people don’t know this, but Mark was actually the first outside investor to actually write a check into the business. He did that on the spot in a Starbucks, in Malibu in 2014. It’s a day I remember with crystal clarity, both because Mark was incredibly gracious and supportive, and also because we really, really, really needed the cash. So Mark, it’s an absolute honor to have you on the podcast. You’ve done so much, really more than anybody I know, to bring the primal and paleo lifestyle into the mainstream. And of course at a personal level, without you Thrive Market probably wouldn’t exist. So thank you for everything and thanks for joining us.

Mark Sisson: Thanks for having me, Nick. And I also remember that day back in 2014, crystal clear. I mean, I remember the sort of the wave of excitement that came over me when you described the mission and it was so compelling. That was the impetus for writing a check on the spot.

Nick Green: Well,  I remember being really, really nervous going into it. Gunnar and I are wondering, how is this going to go? How is this going to go? And you kind of put us at ease right away. So it was a turning point for Thrive. And as I said years earlier, reading and getting exposed to your content was a turning point for my personal health journey, as I know it has been for so many others. Well, let’s dive in. Listeners know the focus of this podcast is on how we can thrive more in our lives. They also know that I like to start with each guest’s personal story or really how you thrive in your own life. And we’ve had different guests on the pod with a lot of stories that kind of start with poor health. So people that are dealing with food addiction, drug addiction, being really overweight, really unhealthy stuff.

And on the surface of it, your story’s kind of the opposite. You were a world class distance runner in the 70s and 80s. You were running over, I think it was a 100 miles per week for years on end. You had top five finishes at the US Marathon Championships, the Ironman Triathlon. You even qualified for the US Olympic trials. And yet as you tell it, your health really paid the price for that. So you weren’t thriving even though you were excelling, let’s say. Can you talk about what was going on there and how that led you to the primal?

Mark Sisson: Yeah, so we go back to when I was early teens, I was interested in health from a very early age. My mother had been reading books on diet and nutrition, mostly by a woman named Adelle Davis. And so I started reading the books that she was reading. I was probably 12, 13 years old and I started get,

Mark Sisson: So I had been very interested in, of all things anti-aging from the age of 12 or 13, kind of a weird, nerdy little kid. I was,

Nick Green: Ahead of your time.

Mark Sisson: Way ahead of my time. And I was scrawny and in the sense that I was too small to play football or basketball or baseball or hockey, which was a big sport in Maine where I grew up.

Nick Green: I grew up in Minnesota, so also hockey,

Mark Sisson: Yeah. You know hockey.

Nick Green: Hockey hot bed. And I was too small to play hockey. I can tell you that.

Mark Sisson: Also, I lived about a mile and a half from school and I found that it was much more convenient for me to run to and from school rather than take the bus. I could literally beat that bus both ways going to and from school. So every day, from the ages of 13, 14, up through when I entered a prep school, I was running, I don’t know, 20 miles a week, just basically for basic transportation. It wasn’t even like I was trying to train for anything. Coincidentally, I was also reading a book in those days, Ken Cooper was a doctor who kind of coined the word aerobics and put a value on the amount of aerobic work you did and said, the more aerobic work you can do, the better it is for your heart and the better your heart is, the stronger your heart is, the longer you live. So that all fell into my game plan of living a long, healthy, strong, happy life.

Nick Green: I’m really curious, this is a bit of a tangent, but I was actually a runner myself in high school. Not nearly as accomplished as you were, but for similar reasons. I was not able to play hockey, football or any contact sport per my mother. And I’ve read a lot about VO two max is a pretty genetically determined thing and does set an upper bound.

Mark Sisson: Yes.

Nick Green: You obviously competed at the elite levels. How much do you accredit to just your sheer aptitude and talent? Your biology, let’s say, versus, running past the bus or whatever.

Mark Sisson: Very, very interesting because as I started out, I would also get bullied by the bigger kids. I mean rural Maine. I grew up in a fishing village, right, 2000 people. Everyone became a fisherman or worked in the tourist trade because there was a bit of a summer tourism. So I got bullied a lot and I was a fairly smart kid. So I placed out of some of the classes and wound up in an all senior PE class as a freshman and just got mercilessly towel whipped and everything else. So along comes spring track and I go out for spring track and the next thing you know I win the mile and the two mile. And by the way, sometimes the pole vault, because I was pretty agile.

Nick Green: As a freshman.

Mark Sisson: As a freshman. So now I’m the high point man on the track team. So that gave me a lot of cred. So that—

Nick Green: And that was probably mostly talent, right, because you hadn’t been training for that?

Mark Sisson: Well, it was some talent. It  was mostly training just because I’d already put those miles in because,

Nick Green: Got it.

Mark Sisson: It did not take a lot to win the mile and the two mile in rural Maine in those days. But as I got more and more involved in competing and found myself, then I went to the Phillips Exeter Academy for the last two years of high school. From there I went to Williams College, and then I was really on this track of competing in cross country and track and field running road races in the summer. And I got faster and faster and better and stronger over the years.

And I always was interested in the performance aspect of how can I improve my performance through either better training methods or with diet and with perhaps vitamin supplementation. So I started really digging into diet and nutrition as a means of improving my performance. And at the time, really the only good research, it turns out it wasn’t very good, was that a high complex [00:08:30] carbohydrate diet was the way to fuel all of those miles. And so I slammed down as many forms of carbohydrate as I could over those years.

Nick Green: By the way, I remember it just to echo that high school, cross country, we would literally do pasta nights before our big meets, where we’d go that night before, eat as much pasta as we possibly could because that was like the way that we would energize ourselves for the next.

Mark Sisson: Every major race in the country had a carbo loading pasta party the night before the event.

Nick Green: Exactly.

Mark Sisson: Yeah. No, that was sort of the conventional wisdom was you had  to consume all these carbohydrates and put these miles in and stay away from fats. Fats are bad. And over the years I got better and faster and stronger and put the miles in. But I noticed that my health,

Nick Green: By the way, just for reference for people, sorry to keep interrupting, but I was training as a pretty elite high school runner and running 50 miles a week, which was considered quite in the upper bound.

Mark Sisson: Yep.

Nick Green: So you, at your peak training, you were doing twice that, which is sort of insane mileage.

Mark Sisson: Well, I mean that was, in those days, you have to understand this was the late 70s, early 80s. Bill Rogers was doing 138 miles a week. And I’m like, God, I got to at least do that.

Nick Green: But you were slacking at 100.

Mark Sisson: I was slacking at 120, trying to keep up at 120, which is probably my max. So I average about 100 miles a week for a seven year period. So yeah, I put the miles in, but I was starting to get injured a lot. I had itises, I had tendonitis in my hips, I had arthritis in my feet. I had  severe irritable bowel syndrome, which I thought was a result of my sort of stress based type-A lifestyle. It turns out it wasn’t. I had GERD, gastroesophageal reflux disease, had bad acne. I mean, I was just falling apart. And here I was theoretically the picture of health, like the iconic cardio based runner, which was again the symbol of fitness and health in this country in those days. I was on the cover of Runners World Magazine three times, but I was kind of dying on the inside.

I mean, it got worse and worse over the past few years of my, several years of my training to the point that I retired. And I just said, this isn’t worth the effort. And partly retired from running because I just couldn’t put the miles in anymore. My arthritis was so bad, my tendonitis was so bad. There was a point at which I couldn’t train more than 20 or 30 miles a week. So I retired and I started looking at what had gone wrong. By then I had a degree in biology, I’d been pre med at Williams College. I had a very strong fascination for evolutionary biology. I wanted to find out what it was about the human species and the DNA that we have that would allow me to be so performance based and excel at such pursuit is running, but then not show the results of it linearly with my health.

So that is really what started my path toward doing research and writing books on what it is about humans that allows us to benefit by building muscle and burning fat and improving our immune system when we do the right things and what are the wrong things that cause us to add on fat, lose muscle, have a decreased  immune system, be inflamed all the time and have pain all the time. And I started to uncover a lot of really, really cool things that worked for me. And then I thought, well, if these work for me, maybe there’s a lot of other people out there for whom these strategies will work. So that’s what started Mark’s Daily Apple, which is my blog that I started in 2006. I really, I just wanted a place to espouse my beliefs and my views. As contrarian as they seemed at the time and to your point, you just made, I mean, they’re not so contrarian now, right, but at the time it was like, wow, what do you mean we should not be eating so many carbohydrates? And what do you mean we should actually eat more fat?

Nick Green: Yeah.

Mark Sisson: Not less fat. And what do you mean exercise is not a great way to lose weight? So all of these, what I call these hidden genetic switches that we all have, that became one of my life’s missions, was to discover these hidden genetic switches and then share that information with my friends and with my readers and with my followers. And if they chose to act on that information, great. And if they didn’t, fine, and I’m fine. Everybody’s got their own lifestyle, their own thing. But for me, thriving was really extracting the greatest amount of contentment, pleasure, joy, enlightenment out of every possible moment in life. And up until the time I retired from competing, I was not extracting a great amount of enjoyment or pleasure. It was struggling and suffering. I mean, you know as having been an endurance athlete, it’s never fun. It’s at best neutral, but it’s never fun. I mean, all your doing,

Nick Green: It’s fun when you finish the race.

Mark Sisson: That’s it. But it’s like when you stop beating your head with a hammer, I guess it’s fun.

Nick Green: It’s like the joke, the guy comes into the room, one’s beating his head against the wall. Why are you doing that? Because it feels so good when I stop.

Mark Sisson: Absolutely. And I think that was the real moment of enlightenment for me when I realized that most of my life I’d been managing discomfort. So my training was about managing discomfort, how deep a hole can I dig for myself and this workout and be able to do it again tomorrow and the next day and the next day. And then the racing is even worse. You’d line up at the starting line and there’s 20 guys there who are equally as genetically gifted, equally as talented, have worked just as hard, want it just as bad that day. But it really, that day, the race comes down to who is willing to manage their discomfort to such a degree that they drag everyone into this,

Nick Green: Pain tolerance.

Mark Sisson: Pain hole with them. And then the race is always one of attrition. It’s who drops off the back.

Nick Green: Yeah. I mean, I remember again, this is high school, so much lower level than where you ultimately competed, but we’d have guys passing out at the end of the race, throwing up at the end of the race.

Mark Sisson: Yeah.

Nick Green: I mean it was literally bodies convulsing as they put themselves to that threshold.

Mark Sisson: Yeah. Meanwhile, the hockey players, the football players, the basketball players, they’re all laughing and joking and having a great time. And they might have lost the game, but they had fun while they were doing it.

Nick Green: Well, it’s interesting to think about it from an evolutionary standpoint, right? Because humans are social creatures, right, and most of the activities, if you think of hunting, you’re working together, you’re going after a goal, it’s dynamic, versus running. You’re like running in a line, pushing yourself basically to that proverbial red line. It’s not an evolutionarily—

Mark Sisson: Well, it’s almost contrary. People would say to me, well wait,  that is kind of primal, Mark, that you ran every day. Well, no, our ancestors would choose not to run every day. It’s a waste of energy to just—

Nick Green: They run when they need to, sprint when they need to, stop—

Mark Sisson: Bingo. Exactly. It was about, and by the way, needing to was a prime motivator because if you’re starving to death, you need to.

Nick Green: You need to. So I want to double click on the primal hypothesis, because as I mentioned at the beginning, and you just alluded to, it’s become a lot more accepted today. But there’s this interesting track through, I feel like starting all the way back with Darwin, an evolution of people don’t want to apply evolutionary thinking to humans, right? It’s like when we look at any other biological system, you look and you say like, all right, well was the environment of evolutionary adaptation, that’s what that animal should basically have in order to thrive. And yet here we are 150 years after Darwin was talking about this stuff. And still at the time, like you were saying in the eighties and nineties, the conventional wisdom was eat complex carbs, and no perspective that was really evolutionarily informed on human exercise, sleep, diet, et cetera. So just for the listeners, can you just distill down what is the insight on primal living? And also, like I said, can you extend it because it’s diet, but it’s also, it’s exercise, it’s sleep, it’s all of it.

Mark Sisson: So the basic premises we are today sitting here, the result of millions of years of evolution, most of which took place in a situation where there was scarcity. There was no food, where there was harsh conditions. The ground was always cold at night and it was always too hot in the daytime. Or there were periods of famine and everything was difficult. And the average lifespan, half of people died at birth, or mothers died in childbirth. I mean, it was a very tough situation. And so, those of our ancestors who survived, survived in this crucible of all of these different challenges to give us today this recipe, this genetic recipe, this DNA set that expects certain inputs. Expects us to eat a certain way, expects us to move the ways in which we moved all throughout human history, expects us to go to bed when the sun goes down and sleep all night and wake when the sun comes up. Does not anticipate that we’re going to stay up under blue light partying until 2:00 AM and then waking up to an alarm clock. So the body has all these expectations.

Nick Green: Expects us to have variability in temperature, right? Exposure to the elements.

Mark Sisson: All of this. A great example, does not expect the body to be at 68.5 degrees ambient air temperature all day long. The body actually expects us to walk barefoot all the time, we’ve only been shod for a thousand years of those two and a half millions of human history. So the Primal Blueprint, my original book, basically looked at, okay, what is it about our constitution? What is it about our genetic makeup that expects us to do certain things? And how have we thwarted those expectations? In other words, our genes want us to be strong and lean and fit and happy and healthy and productive, and live certainly long enough to pass the genetic material, a healthy compliment of the genetic material along to the next generation. And yet we’ve gotten in the way with all of these developments, these creature comforts. Lucky for us, I guess, our brains increased in such a way that we could invent tools and strategies to be more comfortable. And in becoming more comfortable, we’ve become more soft. And in becoming more soft, we become susceptible to the diseases of lifestyle, heart disease and cancer, diabetes, autoimmune diseases. All of these things are-

Nick Green: And when there’s no stress, the body loses its resiliency.

Mark Sisson: Correct.

Nick Green: I mean, you talk a lot about flexibility, metabolic flexibility, and if you’re eating carbohydrates every two hours, every waking hour of your day, and you’re, like you said, sitting at 68 degrees and only moving in very constrained ways—

Mark Sisson: The body says, I don’t need to do anything. I don’t need to get stronger. I don’t need to burn off my precious stored body fat. This is great. If this organism is going to keep eating every two hours, the cells go, hey, I’ll expect fresh supplies of glucose every couple of hours. So the Primal Blueprint was a list of 10 sort of laws. The immutable laws of being human move around a lot at a low level of activity. No, it doesn’t mean going out and running marathons and counting calories. It means just moving around, putting your body through ranges of motion and planes of activity. Lift heavy things once in a while. No, don’t go to the gym every day for two hours and body build if that’s not your thing. But yeah, twice a week, lift some heavy things and you’ll benefit from it. The body expects that. Sprint once in a while. If you look back on human history, our ancestors were always having to sprint for their lives, whether it was to get away from something that was going to kill you or towards something that you were going to eat. So sprint once in a while, get plenty of sleep, eat lots of plants and animals. I mean, it’s basic stuff. Don’t eat processed foods, don’t eat crap.

Nick Green: Well, what I loved about it, I mean I remember reading the Primal Blueprint and then getting onto Mark’s Daily Apple. And it’s like that simple insight, it’s a paradigm shift, right, and everything can sort of follow from it. Once you’re looking to that evolutionary lens, it’s like, all right, yeah, how much is this going to map to what my body evolved and therefore is designed to do.

Mark Sisson: And that was the whole point was that it’s a template.  So it’s not dogmatic list of things as much as it’s a template of behaviors that I describe that allow a lot of leeway within them. What does it mean to eat lots of plants and animals? I guess it means you can eat a lot of plants if you’re vegan or vegetarian. A lot of animals if you’re a carnivore.

Nick Green: It’s a framework. I think the other thing that, and this is a lot of researchers and folks have talked about this, but the range of our environment of evolutionary adaptation was also quite wide. And you can see healthy native populations in different temperatures with different types of diets, different macro breakdown, but there’s these common threads or common-

Mark Sisson: Yeah, that’s a great question. So the answer to which is yes, we all build muscles the same way. We all burn fat the same way. We all boost our immune system the same way. It’s just the degree to which we do it that varies individually among us, largely based on our parents’ contribution to our DNA, which in turn historically reverts back to populations that never really moved much. So if you have a Northern European heritage and for 50 generations, your parents and your ancestors never left Northern Europe, you have a certain way of utilizing nutrients that may differ from a Polynesian family. Which doesn’t mean-

Nick Green: This has been something really impactful in my own life. I mean, we have, on my mother’s side of the family, which is Mexican American, including indigenous Mexican, there is a lot of diabetes. And some of that goes back to agriculture was not introduced as early a stage for that part of our family, as it would’ve been for my father’s side of the family, which was Northern European.

Mark Sisson: And you’re seeing more diabetes now because of the processed maize. The processed corn.

Nick Green: Well, yeah, the current American diet can get diabetes to any human.

Mark Sisson: Yeah, yeah, to any human. But you see it now in Asian communities. I mean, Dr. Ron Sinha, I published one of his books, the South Asian Solution. And it was because 300 million diagnosed Indian population have diabetes, and it’s from rice, and not moving, and crappy seed oils.

Nick Green: So I can geek out on this stuff for a long time and I encourage any listener who’s not deeply exposed to this, it is a paradigm shift. And Mark’s Daily Apple remains 15 years later, the best resource. So check it out if you’re interested in diving deeper.

I want to talk next about how your thinking has evolved over the years. So it’s amazing to me when I look back at the Primal Blueprint, like 15 years ago, you pretty much got it right, but yet you have shifted your thinking and incorporated new things, particularly keto, which it’s very interesting. There’s people that plant their flag in the keto diet, say, I’m like a 100% keto. You’ve taken a different tact, which is this is a tool in my toolkit to build metabolic flexibility. So talk about how you’re thinking has shifted, and I double click on that idea of metabolic flexibility, because I’m sure that’s also a huge thing.

Mark Sisson: Sure. Yeah. So originally it made sense that we would eat more like our ancestor did. And that meant, for instance, at the base of my food pyramid, for the longest time I had a big ass salad. That was the mainstay of my every day was a lot of crunchy, leafy vegetables and some protein-

Nick Green: Which by the way, we’ll segue to Primal Kitchen here.

Mark Sisson: Yeah, yeah. Yeah. And my own life was dramatically shifted when I was 47. I still hadn’t dealt with my irritable bowel syndrome. So here I am from the age of 14 to 47, my whole life is dictated by where the nearest bathroom is. And it was kind of a horrible way to live trying to catalog what city I’m in and where do I know that there’s open bathrooms in the city near me.

Nick Green: And that was even on a paleo diet.

Mark Sisson: No, that was not on a paleo diet.

Nick Green: That was pre-paleo.

Mark Sisson: This is pre-paleo. That was 22 years ago. But it was what begat the Primal Blueprint. And in it, I had already decided that I didn’t need that many carbohydrates. So I was cutting back on carbs in general, but mostly cutting back on crappy carb. The processed carbs, and all the breads, and the pastas and things that I knew I probably shouldn’t be eating so much of. But I was still eating some cereals and things like that. I’d already begun to recognize the benefit of healthy fats. So I was incorporating more saturated fat into my diet, more monounsaturated fats, and recognizing that trans fats were horrible and I could get rid of those. But I still had this gut issue that plagued me. And I still had arthritis in my fingers so bad at 47 that I couldn’t play golf because I couldn’t hold a golf club, or if you and I just met for the first time and you shook my hand, I would cringe at the thought of you trying to out, bro-squeeze me in a handshake.

Nick Green: Wow.

Mark Sisson: So my wife-

Nick Green: And that wasn’t running related if it was-

Mark Sisson: No, not at all. This was all diet related. So my wife said, look, Mark, you’re doing all this research and you’re actually writing about grains and how antithetical they are to health, and you’re writing about gluten and you’re writing about all of the tightly wound proteins and the zine and the phytic acid and all of the sort of antinutrients and things in grains. Why don’t you just stop eating grains for a month and see what happens? And so, it was my wife’s idea and I did, and I stopped, and it transformed my life. It changed my life. My arthritis went away, the irritable bowel syndrome went away. That was, again, huge. The GERD went away. I had all of these things that I had sort of ascribed or chalked up to, well I’m 47, I’m getting up there, this is what comes with aging. I’ll still be fit, I’ll still do my activities, but I’ll struggle through the joint pain. Went away.

Nick Green: Wow.

Mark Sisson: So it was so eye opening to me. That’s when I really said, look, I have to tell the world about that. So that was what sort of transformed me into the pure paleo. I actually read Lauren Cordain’s early work and said, okay, Cordain’s got the right idea. Grains are really antithetical to health. And not just for people who have test positive for gluten sensitivity, but for anybody who you may not even test positive, you may take a food test, but still, it’s worth trying to give it up for a while. So that was-

Nick Green: I know if you got the 80/20 though there, why didn’t you just call it a day? Why evolve towards keto-

Mark Sisson: Yeah, so I got such great results over the next 10 years with just eating primarily, which meant also three meals a day. I was eating breakfast, eggs for breakfast, big ass salad for lunch, steak and veggies and maybe a sweet potato for dinner. And I’ve spent my life chasing performance. So I’m like, okay, I’m really fit now, and I’m pain free, and I’m moving well, what else is there? What can I do now? And so, I started looking into keto, and that’s really what got me reading Fini and Volek and understanding a little bit more about the assumptions that I’d had about the necessity of glycogen in muscles and glucose.

Nick Green: This was like before keto was a thing.

Mark Sisson: Oh yeah, yeah.

Nick Green: Because you also basically ended up being the pioneer.

Mark Sisson: Yeah, yeah, no. This is, yeah, this is now all of a sudden still a long time ago. So I experimented with keto, and keto was basically, you cut out all carbs. Try to keep the fats healthy, but don’t pay attention to calories, just pay attention to hunger. And one of the, so I thought, well, this is great and I can do this. And I was getting great results. My body fat, which was already low, was coming down even more. I probably, to the extent that I could judge or gauge the fact that I was thinking clear, I was thinking clear. And all of these kind of came together. And I thought, this is very cool, but this is not sustainable for me. So what is it about diets and what is it that we’re really looking for that maybe we’re missing? Because everyone’s going, you know, you pick a way of eating. I’m going to be vegan, I’m going to be a fruitarian, I’m going to be a lacto-ovo vegetarian. I’m going to be a carnivore. I’m going to eat paleoish, or whatever. What is it that we’re really chasing? And at the end of the day, none of those diets are horrible if you do them right and some are really good if you do them right, but some are unsustainable if you do them right. What is it we’re really chasing? We’re chasing what I call metabolic flexibility. So metabolic flexibility, which I describe rather overly simply as the body’s ability to extract energy from whatever substrate happens to be available at the time. So the counter to metabolic flexibility is being a sugar burner. So you talked about the body expecting to be fed every two hours. Well, most people are sugar burners. They have never built a metabolic machinery to burn fat efficiently to burn.

Nick Green: And this is also a very evolutionarily informed concept, right?

Mark Sisson: Yes.

Nick Green: Because in an environment of evolution adaptation, you have to be flexible. The timing, the source of the calories is going to be different on any given day.

Mark Sisson: Every  day. So you never know whether the meal you’re eating now is going to be the last meal or there’s going to be another one around the corner. And so the human body evolved with this flexibility to be able to tap into energy stores that we carry around with us. So consider this, in the evolutionary context, we are designed, we are wired to overeat. And so as proto humans, going back 50,000 years, 1 million years, 2 million years, the brain is wired to come across a stash of food, a store of food, and overeat. And the reason for that is that the body has over time evolved these mechanisms to take this excess energy and convert it into fuel that you conveniently carry around with you over the center of gravity. It’s on the waist, on the butt, on the thighs, on the hips. It’s a very elegant system, even for evolution, which tends to be quite inelegant most times. The fact that we could convert excess calories into fuel, carry them around with us, and then be able to tap into the fuel stores when there’s no-

Nick Green: You’re saying the love handles are adaptive. It’s actually that.

Mark Sisson: They’re totally adaptive. Because we’re bipedal. We stand upright so we don’t carry the fuel around on our shoulders because we would fall over.

Nick Green: We’re not a camel. We’re not going to have a hump.

Mark Sisson: And we don’t have four legs. And we don’t have four legs. So with two legs, it has to be centered over the center of gravity. It’s such a perfect system.

Nick Green: I think most people would disagree with you.

Mark Sisson: No.

Nick Green: It’s a perfect system.

Mark Sisson: But here’s the thing-

Nick Green: Evolutionarily speaking.

Mark Sisson: Evolutionary, it’s incredibly efficient. But what happened was, over time, with the access to unlimited amounts of food all the time, we maintain this ability to convert excess calories into body fat, into fuel, and carry it around with us. But we lost the ability, the necessity, to tap into those fat stores and burn them and combust them as fuel. So what I do with talking about metabolic flexibility is I say, well, if you could find a way that you could access the fat that’s stored on your body or the fat that’s on your plate of food, or the glycogen in your muscles, or the glucose in your bloodstream, or the carbohydrate in your plate of food, or the ketones that your liver makes, I mean, if the body is able to be efficiently extracting energy from any of those substrates at any one time, who cares what diet, what way of eating you’ve chosen.

Now, it just happened at the time that keto was probably the best way to do that. It was probably the most, not best, the most convenient, most assuredly, best use of your time. If you can invest 3 to 6 weeks in a keto strategy, you could just be keto for those 3 to 6 weeks, up-regulate, reset your metabolism. In fact, I have a book called the Keto Reset Diet, and then be so good at this metabolic flexibility that you could go back to eating a little bit of carbs. Not a lot of carbs.

Nick Green: The alternative, by the way, is you go directly to consuming your own body’s fat, right? By fasting?

Mark Sisson: Yeah.

Nick Green: Which anyone that’s done that who isn’t fat adapted already knows, it’s just incredibly painful.

Mark Sisson: Well, here’s why it’s so painful if you’re not fat adapted, because if your brain is still expecting you to be providing glucose, if you haven’t built the metabolic machinery to burn fat in your muscles or the metabolic machinery to burn ketones efficiently  in the brain, and the brain hasn’t gotten used to that, the brain, if you starve yourself, the brain just goes, where’s my glucose dude? And if you say, well, I’m not going to eat. I’m going to willpower my way through this and I’m not going to eat. I’m going to burn off my body fat. Guess what? The body goes, well, the brain goes, nah, I don’t think so. I’m going to send some signals down to the adrenals. We’re going to secrete some cortisol. The cortisol is going to go to your muscles and it’s going to melt your muscle tissue down, and you’re going to send a couple of the amino acids to the liver to become glucose so Mr. Brain can be happy again. And it’s this negative feedback cycle that then you tear down more muscle tissue-

Nick Green: Yeah, it’s not good for your body composition and it feels like crap.

Mark Sisson: And you feel like crap and you still aren’t burning any fat because you haven’t built the machinery. So you have to work the system backwards and go, well, how do I build that metabolic machinery? Well, the best way to do it is to eat protein and fat and go longer periods of time without eating and train your body to go, okay, there’s not going to be any glucose, so knowing that, I’m going to be burning ketones. The brain loves ketones. Actually, likes it better than glucose. The brain will burn ketones and stay very happy. And then the muscles will become more and more adapted to burning fat for locomotion to get you around moving throughout the day. And you can get so good at this that you can get 96% of your energy requirements doing six and a half minute miles from fat when you become truly metabolically efficient and metabolically flexible.

Nick Green: Yeah, it was the most shocking thing for me. The first time I tried keto was I had done some fasting before and it had always been so hard, and I always attributed to, well, I’m a skinny guy. I don’t have the fat stores. It just like, I need calories. And after doing keto, I noticed I didn’t have as much appetite. So I was like, all right, I’ll eat a little bit later and a little later, and all of a sudden I was doing 24 hour fast, basically, trivially, once I was  fat adapted. So for any of you guys out there that are struggling with fasting, I will say keto as an entry point, if you’re able to get to a place where you can do keto, even for a few days before a longer fast, it’s a game changer.

Mark Sisson: Yeah and the way we coached it in the Keto Reset Diet was don’t pay attention to calories and don’t let yourself ever get hungry. As long as you’re just eating fat and protein and not carbohydrate, the body will get the message.

Nick Green: You naturally get less hungry, which is so interesting.

Mark Sisson: And you naturally get less hungry, which is fine.  But do not let yourself get hungry. That’s where people go off the rails. So they’ll try to do keto and fasting at the same time cold turkey or starting from scratch.

Nick Green: No, the process of getting fat adapted, doing it with keto is a lot easier.

Mark Sisson: Yeah.

Nick Green: I mean, it’s interesting you pointed out keto is not an easy, for most people, it’s not an easy long term lifestyle. Yet for most people, for short term, it actually is certainly a lot easier than fasting and it’s pretty doable, right?

Mark Sisson: No, no, and even when said that, it’s like, I like food too much.

Nick Green: Exactly.

Mark Sisson: People go, “Mark, you’re so stoic about this whole thing, and you must have such discipline.” I’m like, “No, I don’t have that much discipline at all.” I actually like to eat a lot of food so I’ve crafted a lifestyle strategy around metabolic flexibility that allows me to eat salads when I want to, or have a piece of bread once in a while, or have some fruit and not think anything of it. Certainly not feel guilty that I’ve kicked myself out of keto.

Nick Green: So I really want to unpack that, this idea, because it’s been something that you haven’t written a book about it, but I feel like it’s really core to your philosophy. And that is not denying yourself, engaging in fun, indulging in pleasure of all types, including food. And even, whether it’s the way you work out, you’re playing ultimate Frisbee, you’re not going into the weight room. You’re enjoying that glass of wine at night. And I feel like back to our theme of thriving, it’s like, I know a lot of people think about being physically healthy and having to deny themselves the things that they emotionally or socially love. So talk about the role of fun in your life and how you apply it.

Mark Sisson: Well, again, going back to the comment, the aha moment I had after retiring from competition in endurance activities, which it was never fun. I thought, well, I’m going to make my life about enjoyment and fun. And so with regard to diet, the line I use is I never put a bite of food in my mouth that I don’t think I’m going to love. You made me a great kale salad with lemon dressing on it, and I don’t like kale. I don’t care how good kale is for me, I’m not going to have it. So I want everything I eat to taste great. I know enough when to stop. So that’s an easy part of it. I don’t have to gorge myself on stuff. In terms of my working out, I want to go back, I never answered your question about VO2 max. So I had my genetic composition done. I forget, it wasn’t 23 and Me, but it was one of those sports ones.

And it came back that I was 57% endurance athlete, 43% strength athlete. So that’s pretty skewed towards strength for somebody who was a pretty good endurance athlete. If I was a really world class endurance athlete, I would’ve been more like 80, 85.

Nick Green: More heavily, huh.

Mark Sisson: And my VO2 max at my peak was 67.5. Not a very high VO2 max. So I am the product of massively hard work of just digging-

Nick Green: A pain threshold.

Mark Sisson: Pain threshold, really. And that was one of my strong points. I mean, to my detriment, because now my heart is messed up because of all of the training I did for 30 years. I over-trained. I ran my heart up to max probably 3 to 4 times a week for 30 years. And when I mean max, I don’t mean just for 30 seconds, I mean sometimes for 8 minutes or whatever.

Anyway, so I backtracked and I said, well, how do I want to stay active, stay mobile, enjoy life, and have fun? And so I pick some activities that for me are fun, but are still demanding. I love standup paddling. And so I go and I don’t like to go with anyone else. I like to go alone because I’m out with the manatees in Miami or with the dolphins in Malibu. I pick a pace. I’m in a zone. It’s meditative for me. It’s interesting. It’s so different from running because running, I was always out of breath, pushing the envelope. There’s a different effort level in paddling. It’s a big full body workout, but you’re never really out of breath if you do it right. I love fat biking on the beach. So I ride a fat bike, fat tire bike on the sand.

Nick Green: In the sand.

Mark Sisson: In the sand. Yeah, so I had Thomas DeLauer out with me a couple of weeks ago. Do you know Thomas?

Nick Green: Yeah. I know Thomas really well.

Mark Sisson: Yeah. So he was out with me and he’s like, “Dude, this is awesome.” So we had a great time. And Ben Greenfield’s joining me in a couple weeks.

Nick Green: Awesome.

Mark Sisson: So that’s one of my fun pursuits. And then this week I’m in town. I was in Malibu and I played a Sunday Frisbee game and I played a Thanksgiving Day ultimate Frisbee game. And my son’s a great ultimate player, so we got a chance to be on the same team and play. So I do spend time in the gym, but it is less and less time. Now, I’m not setting any records anymore at my age, so I’m just doing the work just to tune myself up so that I don’t get hurt when I’m playing.

Nick Green: I mean, I think it’s really interesting too, you started Primal Kitchen in your 50s. You sold it in your 60s.

Mark Sisson: I started Primal Kitchen in my 60s and sold it in my late 60s, yeah, yeah.

Nick Green: There we go. And this is a big successful company that you built very quickly. And I was reflecting back on how that started and it really came down to your wanting pleasurable food, right?

Mark Sisson: Yeah.

Nick Green: That was also healthy. Can you just talk about the stuff like-

Mark Sisson: Sure, sure. So as I recognize the importance of food through my writings, through Mark’s Daily Apple, and through the books that I’ve written, and I’ve written seven cookbooks, I recognized early on that when you get rid of the crap in your diet, when you get rid of the processed foods in the center aisle, when you get rid of the industrial seed oils and the added sugar and the colors and the additives and the pies and the cakes and the candies and the cookies, you come down to a pretty short list of things that you can actually eat, meat, fish, foul, eggs, nuts, seeds, vegetables, some fruit and some tubers. And that could be daunting for somebody who’s a foodie, who likes to eat food. So what really makes the difference is what you put on the food. It’s the sauces, the dressings, the toppings, the methods of preparation, the herbs and spices that you use that all of a sudden now re-inject some excitement into this short list of food and allow for millions of different combinations.

Nick Green: Flavor and variety.

Mark Sisson: Flavor.

Nick Green: Yeah.

Mark Sisson: Now I recognize over the years, I always had a Friday recipe, how to make your own mayonnaise, how to make your own ketchup, because I didn’t trust anything in the stores. How to make your own salad dressing for sure, because none of the store bought salad dressing was worthy of my consideration, especially as I started to get deeply into the how negatively the industrial seed oils, the corn oil, canola, soybean oil affect our healths. So I would look at the store shelves and there was nothing that I could buy to put on my salad and I recognize that… Oh, by the way, the second book I wrote was called Healthy Sauces, Dressings and Toppings. And because of the success of the Primal Blueprint, which sold, I don’t know, 50,000 copies the first month or something like that, which for a self-published book, it was pretty good. I printed like 40,000 copies. I think we sold 1,300 copies of this book. It became clear to me that no one wants to make their own sauces, dressings and toppings.

Nick Green: 15 years later.

Mark Sisson: So later, so now cut to… That book came out in probably 2000.

Nick Green: Or 10 years later.

Mark Sisson: No, it came out in 2011 and then 2014, 13, 14, I said, I’m going to start a company that makes really better-for-you sauces, dressings and toppings, things that you put on food. In the old paradigm, you would say, well, mayonnaise taste great, but god, everybody knows it’s bad for you, so use it sparingly or don’t put much salad dressing on your salad because it’s going to ruin those wonderful vegetables that you put on. I’m like, dude, I’m putting this on because I want the flavor. I want to taste all of these different things, so how can I make these condiments and these dressings with healthful oils and super nutrients, super ingredients, if we can, super foods, if we can find them, that people will, sort in alignment with my own thought process, go, yeah, I really would like something that I could put on a burger that I don’t have to feel guilty about eating.

We worked on some salad dressings, we worked on some ketchup, we worked on some barbecue sauces, but the first thing that we were able to commercialize was mayonnaise. I wasn’t even a big mayonnaise guy, but I recognized that mayonnaise was kind of the holy grail of paleo condiments because for the prior 10 years, since the advent of paleo primal keto, there was no mayonnaise because it was so horrible, the stuff that you could buy in the stores. People stopped eating chicken salad, they stopped eating tuna salad, they stopped eating coleslaw, they stopped eating potato salad, egg salad, all these things.

Nick Green: Yeah, you took the canola oil out of it, replaced it with avocado oil and all of a sudden you have a perfect paleo food.

Mark Sisson: I remember you and I discussed early on, because one of our first promos was … Excuse me. I’m not tearing up. One of our first promos was with Thrive Market. I go to my manufacturer, and I’m like, so what’s  the smallest run of this we can do because I don’t know how long this is going to last or whether it’s going to sell. My manufacturer said we can do 12,000 jars. I literally rolled my eyes, like Jesus, 12,000, that’s a lot of mayonnaise, don’t you think? As you recall, it was gone within two weeks.

Nick Green: We used to have huge sections of our warehouse that were just filled with Primal Kitchen mayo. Because it sold so well. At the time there was no product.

Mark Sisson: There was nothing.

Nick Green: Now there’s all these copycats, but there was nothing like it at the time.

Mark Sisson: People ask me how I feel about that. It’s be careful what you wish for. My mission statement was to change the way the world eats. Part of that was done through my blog, Mark’s Daily Apple. Part of it was done through my books. Much of it was done through my creating products that people, who otherwise would not be eating healthy, would use as sort of a transition. Oh, this looks interesting. What is it about this product that’s so healthy? Oh, wow, let me look into this way of eating. People’s lives have been transformed from that side, from the commerce side of buying our products and then backing into a primal or a paleo way of eating.

Nick Green: Totally. In so far as you created imitators, it’s like that also changed the industry. That’s raised the bar further.

Mark Sisson: That’s leverage. That’s leverage. Sorry. You got to my point. Thank you. That was the leverage I was talking about. Be careful what you wish for. Change the way the world eats. If a hundred companies change how they’re making products to feed the world, and that changes how the world eats, then my mission has been successful.

Nick Green: A Fortune 500 business, like Kraft Heinz, can come and say, hey, we want some of this. You’re all of a sudden able to change how they think about CPG internally.

Mark Sisson: That’s been massive.

Nick Green: Pretty incredible. The reason I asked that question about the genesis of Primal Kitchen is one, I think it does tie to that philosophy of fun that you started a company so that you could have the pleasure and food that you weren’t able to get from store-bought dressings and condiments. The other reason is, I think it’s this through line in your career, which I find amazing of you didn’t have a master plan of I’m going to build a hundred million business or I’m going to go …

Mark Sisson: I didn’t intend to become the Mayo King of Malibu, no.

Nick Green: Yeah, or for that matter, to become a multi-time New York Times bestselling author or have this blog that would become the kind of pinnacle of primal living. Each step, it was like, hey, this is something I want. It doesn’t exist. I’m going to go create it. All of a sudden the snowball gets rolling. Just as an entrepreneur, I find that so resonant as just the way entrepreneurship really works.

Mark Sisson: That’s how it worked for you and Gunnar.

Nick Green: Totally. You feel like it’s one step in front of the other, and all of a sudden great things can happen. Shifting gears to a totally different topic. You’ve alluded to this a couple of times, but before we got on for the interview, I asked, “You’re 66, right?” You’re like, “No, I’m 69.” Actually until earlier today, I thought you were in your early sixties. 69 is a time when a lot of people are slowing down. I think about my parents and their generation. You were starting businesses in your sixties. You’ve said, I think pretty recently, that your body composition is still similar to what it was in your fifties and forties and young thirties. Staying lean, active, cognitively sharp, that’s what everyone wants as they age. We’ve gone through a lot of what maybe is your secret, but is there anything else that you attribute that ability to stay young and have that health span be so good?

Mark Sisson: I would say diet is huge. Diet is a major part of that. Staying active, absolutely huge. When you talk about longevity, you talk about the ability to move around the world. Why do I want to live to 95 if I can’t go visit places and go travel and walk around and hang out with friends? Then the cognitive side of that, why would I want to live that long if I can’t remember great memories, or if I can’t participate in spirited conversations and witty repartee? I hang around with young people, and that is … I don’t know what they think about me, this old fart hanging around them, but I hang around young people. I try to adopt the latest lexicon, latest jargon of the young people and participate in conversations. The kids I play Ultimate with, they’re 20 somethings, but there are 30 somethings, and there’s a couple of 50 and 60 somethings in that game, but it’s a young person’s game.

Nick Green: Yeah. It’s interesting, people say you are who you’re around, and being with younger people that have that vibrancy and energy probably drives some of that as well.

Mark Sisson: Yeah. Yeah.

Nick Green: That’s interesting. I’m really curious, and I think I know at least one answer you’re going to give to this, but you seem to have achieved a lot young, but then also continued to achieve into your sixties now. Are you done or what’s next?

Mark Sisson: I sold Primal Kitchen in 2019, and I tried to be retired, and it didn’t work, so I started a new company with my son. It’s a minimalist footwear company. It’s called Peluva. We launch the first quarter of 2023, very excited about it. I think it’s going to revolutionize the way the world walks.

Nick Green: By the way, you’re wearing a pair of them in here.

Mark Sisson: Yes.

Nick Green: When you walked in today, I stood with you for 10 minutes, didn’t know. You’re dressed very fashionably, and these shoes have five fingers. Every pair of shoes I’ve ever seen with five fingers looks quite strange. These look like they’re stylish shoes that you’d wear out to a …

Mark Sisson: Thank you. We think so. The intention was to bring the concept of a toe splay.

Nick Green: Fashion forward.

Mark Sisson: Fashion forward, right, exactly. I’m anxious to see what the Thrive Market members are going to think about these.

Nick Green: You’re going to start the footwear category.

Mark Sisson: Okay. That’s right. Let’s do it.

Nick Green: I don’t know how we’ll manage the sizing.

Mark Sisson: We started categories before, Nick.

Nick Green: That’s true. That is true. Q1 of 2023 that you guys go live. That’s exciting. All right, we’re going to do the end of the interview. One thing I like to end on is just-

Mark Sisson: I just have to … The name of the company is Peluva. P-E-L-U-V-A. Go to peluva.com.

Nick Green: It’ll be primarily D2C then, same as … ?

Mark Sisson: Yes. Yes.

Nick Green: Very cool. Okay, Q1 2023, peluva.com. I like to give the listeners some really tangible takeaways, so I want to do a rapid fire thing. Give me your … Let them kind of get into your world. I’m going to say a few different top fill-in-the-blank.

Mark Sisson: Okay.

Nick Green: You tell me what would be at the top of your list. First one is top animal-based food for you.

Mark Sisson: Oh, lamb chops.

Nick Green: Lamb chops. That’s an interesting one. Lamb chops are controversial, I’ll tell you that, in my home. My wife will not do lamb chops. Top non-animal-based food.

Mark Sisson: Non-animal-based food. You got me there because I was going to say cheese. Cheese is animal-based. As I go down my list, they’re all… There’s animals there somewhere.

Nick Green: No part of you is vegan. I can tell that.

Mark Sisson: No. Tart cherries.

Nick Green: Tart cherries, good. Supplements.

Mark Sisson: Collagen and vitamin D.

Nick Green: Top exercise for cardio.

Mark Sisson: Lifting weights.

Nick Green: Okay.

Mark Sisson: No, everything you do is cardio. When you go to the gym, and you lift weights, especially if you’re doing high-intensity work, it’s cardio. Your heart’s beating. I would say stand up paddling is my top cardio exercise, but in general, as advice for anyone, every time you go to the gym, it’s cardio.

Nick Green: Then top for strength. This one, in your sixties, still maintaining a strong, lean physique, how do you that?

Mark Sisson: Hex bar deadlift.

Nick Green: Deadlift, okay.

Mark Sisson: Hex bar deadlift.

Nick Green: Hex bar deadlift. That’s the one where it’s like a box around you.

Mark Sisson: It surrounds you.

Nick Green: Yeah. Yeah. Which is much safer too.

Mark Sisson: Much safer. Yeah, I wouldn’t do a regular deadlift now.

Nick Green: That’s great. Most important health metric that you track.

Mark Sisson: Most important health metric that I track. How I feel, and I’m going to be really— I’m the anti quantified self. I’m the anti biohacking guy. I hate bio. I hate the term biohacking. I don’t do wearables.

Nick Green: You’re not checking your HRV to gauge your energy when you wake up?

Mark Sisson: The only thing I do wear is I wear a full heart EKG system sometimes when I ride because of this issue I’ve had with my heart. I just want to check in once in a while, but that’s a full on EKG. That’s like a medical device, where I’m actually going out and putting myself through …

Nick Green: You’re not recommending that for the listeners?

Mark Sisson: No, no, no, no, no. It’s an amazing device. It’s a Frontier X machine. It’s a spectacular machine. That’s the only wearable. I don’t do sleep tracking stuff. I don’t do HRV. I can’t do HRV because my arrhythmias are already built in. Step counting? Please. I went to Europe this summer. We walked between six and 12 miles a day, every day. Everybody’s wearing their Fitbit and their loop and their trackers, and I’m like, I don’t care. It felt good. We walked … I know sort of in my head how many miles we walked. That’s all I care about. I don’t care about steps. I would say the number one metric I use is how do I feel? How did I sleep? I slept pretty well, or I didn’t sleep that great. I don’t need a device to tell me.

Nick Green: Yeah, I love that. It ties back to that having fun and getting pleasure out of life.

Mark Sisson: Yeah.

Nick Green: You alluded to this earlier, but being high-intensity, competitive, Type A person, I think so many of us want to go towards quantify everything, track it all, et cetera, et cetera.

Mark Sisson: HRV’s another example. People depend on HRV to tell them whether or not to work out or whether or not to work out hard. I’m like, no, do I feel like working out hard or not? If I do, and I don’t feel good, I’ll walk home. I don’t need it to annex my health to a device.

Nick Green: You fly by sight. Last one is top guilty indulgence, or maybe you don’t feel guilty about it, but what’s an indulgence for you?

Mark Sisson: I’m the one guy that eats fruitcake.

Nick Green: All right. I have a sweet tooth too, so I can relate to that.

Mark Sisson: Once a year I’ll have fruitcake by… Not once a year. It gets sent to me during the holidays by several people, so it’ll last for a while.

Nick Green: Yeah, that’s a good one. All right, and then we have two things that we like to ask every person. First, what does thriving mean to you?

Mark Sisson: Thriving means extracting the greatest amount of enjoyment and pleasure and contentment and fulfillment and love out of every possible moment.

Nick Green: Love that.  In the spirit of constant self-improvement, which I know you’re obsessed with, what is an area that you want to thrive more? What’s one area you’re still growing?

Mark Sisson: I’ve signed up for a breath hold workshop in January, and I’m looking forward to that because that’s always been an issue for me, whether it was swimming or diving. It’s just one of those areas I think I need work.

Nick Green: That’s really interesting. It feels like breath work is becoming a whole thing right now.

Mark Sisson: This is holding your breath, so this is breath hold,

Nick Green: Maximum breath hold

Mark Sisson: Maximum breath hold.

Nick Green: Wow. What’s your max right now?

Mark Sisson: It’s probably a minute and 30 or something like that.

Nick Green: We’ll check in afterwards.

Mark Sisson: Yeah, yeah.

Nick Green: All right. That’s it. We’ve probably gone over, but this was an awesome conversation, so thank you so much, Mark.

Mark Sisson: It’s my pleasure, Nick.