Strong convictions, loosely held: how Peter’s views have changed (AMA 90 sneak peek)

1. 0:00 – 0:11

   Intro

   1. PADr. Peter Attia0:00

      [upbeat music] Hey, everyone. Welcome to the Drive podcast. I'm your host, Peter Attia.

   2. SPSpeaker0:04

      [upbeat music]

2. 0:11 – 4:10

   Strong convictions, loosely held: changing opinions as evidence, expert conversations, and clinical experience evolve

   1. SPSpeaker0:11

      Peter, welcome to another podcast. How you doing?

   2. PADr. Peter Attia0:13

      Very good, thank you. You?

   3. SPSpeaker0:15

      Doing good. Doing good. So today, we are celebrating 400 episodes, about eight years. So we recently crossed this, and usually what we do is every now and then we'll look back at kind of a reflection episode. In the past, we've always referred to them as strong convictions loosely held. And so I think as we start, and before we get into specific topics, do you kinda wanna remind people about what that term means to you, where you heard about it, and why you think it's so important?

   4. PADr. Peter Attia0:41

      Yeah. It's a term that I first heard from a friend who, uh, ran a hedge fund, and obviously this was through the lens of his investment thesis, um, which was that obviously you needed strong convictions, but you-- because you're putting r- you know, real capital behind a thesis. Um, but those convictions had to be loosely held because the moment new information or contradictory information showed itself, you kinda had to be willing to, um, check your ego at the door, say, "Maybe I was wrong," and, "How do I need to change things?" Um, but I always thought that that frankly sh- was, was a great, you know, view of how to think about everything, uh, where there's actual information at, at, at, at play and, and obviously medicine and science are great examples of that. So, um, I've been around many really, really great scientists, um, and one of the characteristics they all have in common is they're not married to a particular thesis being right. They're married to sort of getting things as right as possible and reducing uncertainty, um, by following the data wherever those, wherever those data take them. So, um, yeah. I, I guess, uh, you know... I, I think it's, um, important that we are revisiting our assumptions, and as someone asked me once, um, you know, "If you were to write Outlive 10 years from now, do you think it would be the same book that you wrote, you know, three years ago?" And, uh, I would say no. I, i- in fact, that would be concerning if it were the same book in 10 years as it was at the time it was written. Uh, 'cause it would either suggest I'm too rigid in my thinking or science has made no progress h- and, uh, I think both of those would be, would be challenging. So, um, yeah, that's loosely how we, uh, think about this episode.

   5. SPSpeaker2:23

      And Peter, when you're kind of looking at your opinions and how you're thinking about things and how they evolved, where does that traditionally come from? What are the triggers that are causing you to potentially change your opinion or how you look at things?

   6. PADr. Peter Attia2:36

      I think it's a combination of obviously things that change in the literature, um, but you know, scientific progress is, you know, by its very nature somewhat glacial, um, and episodic, right? It's not like mono- you know, it, it doesn't just progress at the same rate. Um, um, but so I think the other sources of, of learning for me and things that force me to change maybe things I once held, uh, would be the, the podcast itself, right? There's a opportunity I get most weeks to sit down with someone who's far more of an expert in a subject matter than I am, and both in preparing for that discussion and having that discussion, I'm learning something that often changes, I mean, almost always changes something in how I think. Um, and then obviously you have, uh, as every doctor hopefully appreciates, all of our patients are kind of our teachers, right? So, um, we, we learn a lot because we're, we're seeing what happens in a clinic with patients and we're, um, you know, we're gonna talk about some of these things today, frankly. Uh, so, so, so basically I think all of these things taken together, um, whether it be literature, conversations with experts, and seeing what, what actually happens in the, in the clinic. I think, um, a lot of times these things continue to converge, and the views don't change much, and other times the view just gets more nuanced, and you start to carve out edge cases and exceptions. And then sometimes it actually causes you to change course completely. Uh, and obviously that's what I think this episode's all about and what, what makes this type of episode, for me personally, quite enjoyable.

3. 4:10 – 10:59

   Nutrition: Peter’s evolving view of ketogenic diets, energy balance, and dietary dogmatism

   1. SPSpeaker4:10

      I think as we start this, I think the topic that makes the most sense to start at, which is everyone's favorite, nutrition. So kind of very early on, way back in the day, um, you were a big proponent of the keto diet. You were also an early adopter and advocate for kind of extended fasting and what that could potentially do from a longevity perspective. And so kind of where are you now on those things, and how has your opinion changed?

   2. PADr. Peter Attia4:36

      Well, um, my original thinking, I'll start with the diet thing, was, was really driven by this insulin model of obesity. Um, so m- metabolic disease was and obviously remains kind of, um, not just one of the four horsemen of chronic disease, but kind of the foundational problem, right? So it's the, it's the one thing where as, a- as metabolic health gets worse, your risk of all other chronic diseases essentially goes up. Um, and in my own journey of nutritional experimentation, carbohydrate restriction was proving to be very beneficial. And as you stepwise move down the plank of carbohydrate restriction, you're gonna pretty quickly find yourself at a place which is generally a line in the sand of ketogenic diets or not, right? Because at some point, carbohydrate intake gets so low that you're not providing enough glucose for your brain. But if it's still a little high and it's too high to, um, allow your body to switch over into ketosis, then you're not getting enough supplemental energy for your brain, and you're, you're in that kind of no man's land of hell. And so I remember getting to that point and then deciding, well, you know, I at that point had been reading a lot about ketogenic diets and decided, "Look, I'm gonna give this thing a shot." So anyway, so that-- my own journey starts with my own experience, which was very positive. Um, I know I get sort of, uh, labeled as someone who's anti-keto diets and stuff like that, um, by, by various people out there and, and I, I just find that to be the most comical, uh, critique of me because not only was I on a ketogenic diet for three years, it was probably the best I ever felt. Um, I, I look back at, you know, what those three years were like, and, and every element of it was, was very positive for me. Uh, there are other reasons, obviously, I chose to abandon it. Nevertheless, um, it reinforced the, the, the model in my mind that, um, the relationship between carbohydrates, insulin, hyperinsulinemia, uh, lipogenesis, et cetera, um, was, you know, sort of, um, it, it all made sense that then a ketogenic diet would sort of fix these problems. Um, I think there were also lots of compelling, um, data with, with animals and humans showing the improvements in glycemic control, insulin sensitivity, liberal-- liver visceral fat, et cetera, um, and other metabolic markers improving. And as I said, I, you know, certainly reinforce that. Now, here's what's different. Um, I abandoned the ketogenic diet basically because I was just tired of being that restrictive in my eating. I mean, I was very strict in my, uh, ketosis. Um, I think, you know, I also logged unprecedented amounts of data during this process, and I think over a three-year period of time, you know, my average morning fasting, um, beta-hydroxybutyrate level was, you know, 1.8 to 2 millimoles, something in that range. So this wasn't-- Like, I wasn't sort of a light ketosis guy, and then, of course, it would get much higher during the day, depending on what I was eating, as-- 'cause I was mostly eating fat. So my abandoning the ketogenic diet was independent of my views of the ketogenic diet, and to this day, I still view it as an effective diet. What has changed is my belief as to why it works. You see, I used to believe that the diet worked through insulin suppression. Um, but today, I, I don't think that's the case. Today, I think the diet works, um, for the same reason many restrictive diets work, which is it makes it easier to control energy intake, um, even if you don't have to think about it deliberately, which to be clear, I never did, right? Um, now of course, I wasn't losing much weight on a ketogenic diet 'cause I had already lost most of the weight I was trying to lose just from carbohydrate restriction. But when I see people who are successful on ketogenic diets, they often report that they feel quite satiated, and I think that has to do with the type of foods that they're consuming, which, which satiate them more than carbohydrates. Um, and I also believe there's something to be said for when you are, um, oxidizing fatty acids, that in and of itself is providing fuel endogenously, which is happening obviously during a period of weight loss. So it's a subtle point, but it's, it's worth making because it does reflect a change in my viewpoint, which is that the, um, the metabolic dysfunction, the visceral fat accumulation, the ectopic fat accumulation, the insulin sensitivity deteriorating, all of these things are the result of the energy imbalance, and hyperinsulinemia is along for the ride. But if you magically address the hyperinsulinemia without addressing the energy imbalance, you're not gonna fix these problems. And the easiest way to see that is to watch a person who's on a ketogenic diet who, for whatever reason, is still in energy imbalance. So they're still gonna have lower levels of insulin, but they're not gonna lose weight, and they could even gain weight. So you could gain weight on a ketogenic diet if you're out of energy balance. Um, so that's, that's sort of the long and short of, of my views on that. Um, as a result, I think it's made me less, I mean, much less dogmatic about the strategy or the tactics that a person employs, um, when it comes to reducing, you know, energy intake. Um, I really don't have a strong preference when a patient is at a point where they need to reduce intake. Once a few principles are met, and we've obviously talked a lot about those things, right? I really am pretty adamant about people maintaining the, the right amount of protein, and at a minimum, I want them hitting 1.4 grams per kilogram of body weight. But if they can accomplish that on a ketogenic diet, on a low-fat diet, on a, uh, you know, on a mostly pescatarian diet, I mean, again, it just doesn't really matter as much to me, um, as it, as it once did. So, um, yeah, I think that's, that's probably a, a big point around, uh, the, the sort of my previous dogmatism around nutrition.

   3. SPSpeaker10:58

      And now

4. 10:59 – 17:55

   Extended fasting, autophagy, lean-mass loss, and who may benefit from prolonged fasting

   1. SPSpeaker10:59

      looking at extended fasting, do you wanna talk about kind of what was your initial motivation there and where your thinking has evolved?

   2. PADr. Peter Attia11:06

      Yeah. I mean, I think it's sort of similar. Again, a lot of things with me begin from a place internally, right? Where I'm doing something and I'm trying to push the boundaries of it personally. So for an about a three-year period of time, um, I was doing a quarterly fast, and it would be anywhere from seven to 10 days once a quarter, and then on the other two months of the quarter, I would do a three-day fast. Um, and what was my logic for this? I mean, to be clear, I was not trying to lose weight. I was at a weight that was perfectly reasonable. Um, but I was really fascinated by this idea that, um, with enough nutrient deprivation, we could promote enough autophagy, uh, that it would have real health benefits. And just to remind folks what autophagy is, um, autophagy is the process by which cells break down and recycle, um, old intracellular proteins and structures. So the name auto, self, phagy, eating. It's literally cells that are kind of eating themselves. And, and this is a very important, um, process, obviously long, long conserved in evolution because when nutrients are scarce the body has to basically reuse and recycle things. Now, the benefit of this, of course, is that what, what is the body gonna do when it needs to reuse and recycle things? It's not gonna start with the best stuff. It's gonna start with the worst stuff. So if you have cells that are heading towards senescence, if you have cells that are developing mutations, the thinking goes, "Hey, that's where we're gonna start. Those are the cells we're going to get rid of and recycle for their constitutive components." And again, in preclinical models, extended fasting, uh, clearly, uh, does this. So there's, there's little doubt that extended fasting, um, uh, promotes autophagy. As a little aside, Nick, um, and I haven't looked at the literature on this in a couple of years, so maybe what I'm saying, someone will say, "No, Peter, we actually, you know, look at so and so study." But, but it wasn't really clear, um, how many days of fasting were necessary to get into, quote, "high autophagy." Because autophagy is not digital, it's analog. It's not like you have no autophagy and then you cross a threshold and now you have autophagy in a digital switch. It's, it sort of ramps up, kind of like ketosis. Now, in ketosis, we have a threshold we use. It's about somewhere between 0.5 and 1 millimole resting or fasting. Um, we don't even have a unit of measure in autophagy to do that. But having spoken with, you know, the experts on this subject matter and looking at preclinical data, um, somewhere around three days seemed to be where, where you could really sort of juice autophagy levels beyond what you would get from exercise or other things like that. Okay, so then the question becomes, "Well, why aren't you doing that still, Peter?" Um, and again, I think there are several reasons for that, but I think what changed most was kind of the evidence, but also the cost. Thank you for viewing this sneak peek of an Ask Me Anything episode of The Drive. As a premium member, you'll get immediate access to the full AMA episode you just watched a sneak peek for, our entire back catalog of AMA episodes, and all future AMA episodes. You'll get longevity-focused premium articles packed with actionable insights. You'll get unrivaled show notes for each and every episode of The Drive, and much more. Become a premium member today at peterattiamd.com/subscribe. Thank you for listening to today's sneak peek AMA episode of The Drive. If you're interested in hearing the complete version of this AMA, you'll want to become a premium member. It's extremely important to me to provide all of this content without relying on paid ads. 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Episode duration: 17:55