Why Dr. Peter Attia Changed his Mind on Fasting (and 4 other Longevity topics)

Dr Peter attiev, we all change our mind on things. I want to go into some detail with some things you've changed your mind over the last five years. Let's Just Jump Right In. Let's start with a couple in nutrition. So I think the the the first one that I would say I've changed my mind on is the importance of regular fasting. So I used to really do a lot of regular fasting, probably considered excessive by by some, so probably did a seven day, seven to ten day water only fast once a quarter in a three day water only fast once a month, and I think, while there were clearly some benefits of doing that, I think you know it's very difficult to measure what's happening cellularly, but my belief, at least, was that the benefits of that outweighed the downside. The downside of doing that, by the way, is you're going to lose a lot of muscle mass. You know, as much as you might exercise during those periods of fasting which I tried to, you know you're just not going to be able to maintain lean mass. So you, you, basically I- was always sort of accumulating a little bit of a debt of lost muscle mass and over a period of about three years I probably lost about 10 pounds of lean mass, and so today I just don't feel that that trade-off is worthwhile, at least at that extreme level that I was doing, and so I don't. I haven't done a prolonged multi-day fast since the end of 2020, actually. Show more

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I just I recommend them. If you're going to get it, you're going to spend a fortune at the grocery store. Macadamia nuts are not the cheapest nut, but using that discount you can save a few bucks. I'm getting some good macadamia nuts from House of macadamia plus. With any purchase using that link, a free 20 ounce bottle of cold pressed macadamia nut oil- literally the only cold pressed macadamia nut oil that I know of that's on the market and you're getting one completely free if you just use that link down below. There's no catches, it's just to get the word out there. Where do you stand nowadays on the occasional 24 hour or the occasional 20 hour? Yeah, I think that's totally fine. Yeah, yeah, okay, what else another one in nutrition is? Show more

I've really had a change of heart around agriculture, right. So I used to sort of subscribe to the view that there was nothing wrong with GMO, like just from a scientific basis. I always felt it was misunderstood, right, like GMO is really just a crop trait strategy, right, so GMO is modifying organisms to make them resistant to pesticides and you know, I thought that people's opposition to that was a little conspiracy theory-ish. And you know, there's nothing wrong with a plant that was genetically modified. I also felt that sort of the entire organic industry was kind of a scam, sort of masquerading, as you know, kind of a- you know a tribe of you know, like a food tribe, basically just another sort of dietary phony altruism. Show more

Yeah, yeah, yeah, I have a much more nuanced of that today, and I would say that I do have actually more concern of GMO today, again not because of the actual Gene modification of the plant, but because of the herbicide, because of the pesticide. I don't think we have sufficient long-term data on the effects of glyphosate and I think that we have been probably overly concerned with acute toxicity, which is, I would be fairly comfortable to say, the acute toxicity of glyphosate and herbicides and fertilizers is very low, if not non-existent. Show more

But I don't think we have sufficient data on The Chronic side and therefore I think that the the precautionary principle would actually suggest we're doing this incorrectly. And so, on a personal level, today I am far more interested in what I'm learning about regenerative agriculture and the principles of optimizing around nutrient density as opposed to yield. Furthermore, the more I learn about this- and I would still consider myself quite early in that Journey, having only read, you know, three books on the subject matter so far- but it's been very influential and it's really shifted my thinking about this to the point where I'm now basically asking the question. Yes, I think organic is still a bit of a bad term because it doesn't mean anything and organic food can still be horribly grown. But there's something in this about the importance of how we grow food and, to the best of my understanding right now, I think if I could wave a magic wand, I would never eat anything that was not produced regeneratively, meaning crops that are grown not as mono crops, not without cover crops, without using any nitrogen spiking, but rather done through this longer life cycle of regenerative production. What does nitrogen spiking actually do? I'm curious. Well, what it's basically doing is altering the soil environment. Show more

So, just as we are pretty familiar with how we have our gut biome, the soil is the biome of the plant, and when we nitrogen Infuse, that, which was really a process that was started kind of roughly around World War II, which is really when we saw crop yields explode, right, we, you know, we had historically been producing about 20 bushels per acre per year of corn globally, let's just say in the United States even, for you know most of the modern history- and and then, post World War II, that number has just gone up and almost increased in some places tenfold. So, you know, in the United States today, you're probably seeing 140 to 200 bushels per acre per year of corn production, and that came through a lot of things that you know involved just pumping more and more nitrogen in, because of course, plants have to fix nitrogen externally and carbon from the air, but what that's done is completely changed the health of the soil and so, at the risk of being a bit sort of cute about it- you, if you don't have healthy soil, you won't have healthy plants. If you don't have healthy plants, you won't have healthy animals. If you don't have healthy animals, you don't have healthy humans. I think we're kind of in a little bit of that life cycle, and while I don't think that this is something that you know can't be managed, I definitely have worry about long-term soil health and as a result of that, I I I've become much more interested in something that I had been quite dismissive of in the past. Yeah, well, it's, it's a good way to look at it. As far as GMO inherently isn't the problem, it's the fact that that's sort of a canary in the coal mine for okay, well, what are we protecting this plant from? Show more

Does that indicate that there's more crap on this plant? Yeah, you know, and that's a really interesting way to look at it. All right, what's next say overall on just exercise in general, I think, despite the fact that I've been a lifelong exerciser, I love exercise. Show more

It's always been kind of enjoyable to me. It's never been something that's required like discipline. I've got to make sure I got an exercise. I don't think I fully appreciated how powerful exercise was as as a drug. Frankly- for lack of a better word- until really the last five years I think I had, you know, sort of thought it was beneficial, in a sort of holistic way, but I don't think I understood what its effects were specifically on the brain, what its effects were specifically on the nervous system, what its effects were on the cardiovascular system at a really deep level and and and overall, what its effects are in terms of lifespan and health Span, in other words, how much it reduces all-cause mortality and how important it is at preserving quality of life, which, again, it seems pretty obvious. Show more

But I think I had been overly fixated on nutrition and that that just came at the expense of me thinking really long and hard about exercise and how we need to be more thoughtful in our application of that tool. Has that changed how you personally exercise and I'll couple that with: I know you have a different life circumstances now, you're focusing on different things and that's changed how you look at exercise. Show more

But has your view of exercise itself changed, how you exercise? It certainly has, because if, because this is the first time in my life where I'm truly time Limited, so up until I was, you know, in my early 40s, I don't know- even though I was always busy, I, I've somehow always had seemingly as much time as I wanted to exercise and therefore I could always kind of just pursue my Bliss in that, whatever way I was doing. Show more

Now I'm truly limited by time, I really. I mean, if I had more time, I, if I had more time to exercise, I would today, but I can't. I'm really stuck at, you know, what still sounds like a lot for people, but for me is historically low. You know, 10 to 12 hours a week is the most I can really make time for. With the other commitments I have that are more that I deem, you know, for any marginal time, I would deem those other commitments more important. So, yes, in that sense my view is much more disciplined about how that time is spent. You know, if it were 10 years ago, I might use that time today to just focus on one thing, whereas now I have to spread that time out across stability, strength, low end aerobic efficiency, high-end Peak aerobic output. I have to spread it across those four pillars. Show more

So if you could go back to say prime time, maybe early 30s or, you know, whenever you were putting a lot of time into your endurance work, if there was something that you could do differently than what would it be? Show more

Well, I would still allow myself to kind of pursue my Bliss right. So in my early 30s- or, yeah, in my early 30s, I guess mid-30s it was swimming, ultra distance swimming- I think I would have just been a little more thoughtful about what I was doing in dry land. So instead of spending, you know, 25 to 30 hours a week swimming, I should have been in the weight room at least you know, three hours a week. On top of that same thing, when I was at, you know, when I was just cycling non-stop, I think I could have been more thoughtful about other types of activities to balance out some of the obvious imbalances that come with being crunched over on a bike all day. Yeah, I think I can speak for myself with- yeah, I mean resistance training. I probably went too full bore into that for a while, where, you know, I had to unravel walking like a robot for quite a while, you know. And so, okay, what's what's next on the list here? Probably my skepticism for the use of Metformin as a zero protective molecule. So metformin is a drug that has been widely used for the early intervention of patients with type 2 diabetes and even patients with, you know, severe insulin resistance who are not yet type 2 diabetics, and in that regard, it's been a productive drug. So it it seems to work by reducing hepatic glucose output, and so, in other words, it works by putting less glucose into the system. But, of course, it became a drug of interest about a decade ago because of some epidemiology that suggested that people who took metformin with type 2 diabetes had better odds at surviving cancer than people who didn't have diabetes and didn't take metformin. Show more

And that was an enormous suggestion, because we understand very clearly that people with type 2 diabetes are at a much greater increase for cancer. So how is it that people with this disease, who have a much higher incidence of cancer if they take this drug, seem to not get cancer at the same rate as non-diabetics who don't take the drug, and there's clearly some interesting mechanisms of action for why that might be the case. It could be that, you know, activation of ampk itself is protective. It could be that just lower in glucose and lowering a growth factor like insulin and igf is protective. There are lots of explanations for this and as a result of that- gosh- I mean, I was taking metformin prophylactically. Ie is zero protective agent. Starting in about 2011 is when I began taking it- and by about 2018- 2019, so about five years ago, you know- I noticed a couple of things that I didn't like. One was, as I track my lactate levels, I noticed my lactate levels were always higher than I thought they should have been. Show more

This was most notable even at rest and also doing kind of zone two activity. That might not be surprising when you understand how metformin Works, which is- it's at least in part- a weak mitochondrial toxin. So if you're poisoning the mitochondria just slightly, which is what you're doing to get that ampk activation, you're also impairing somewhat oxidative phosphorylation and that's why you're going to see a higher lactate. That struck me as not a great idea, at least in a person who's capable of exercising greatly, as I am and many of my patients are. Furthermore, there was a a study that came out quite recently that only had me kind of double down on that thinking, which was it was a repeat of the epidemiologic analysis that suggested that metformin was beneficial relative to non-use in non-diabetics, but just done on a different cohort of patients and, frankly, done a little with a little bit more statistical rigor, and it came to the opposite conclusion. Show more

It came to the conclusion you would expect, which is that patients with diabetes who take Metformin still actually fare worse than the other than non-diabetics not taking metformin, when adjusted for all of their variables. And you know, for reasons that I cover in a newsletter that I wrote, which you know we can maybe link to, I find the latter study more compelling, not simply because it agrees with my newfound thinking, but because I simply think it's a more reasonable scientific analysis. Ultimately, we will find this out one way or the other, because there is a clinical trial that is going on that's asking this question, and so my hope is that in five years we'll just have the answer and we won't have to rely on this indirect Insight or indirect information that's always going to be prone to biases and therefore is ultimately not dispositive in helping us understand this. Show more

And if we're sitting here in five years, in the tame trial- which is the name of the trial- found that metformin is indeed zero protective, I'll be the first one to be taking it again. So a question that I've always had. That might sound like a total Noob question, but if, if metformin is a mild mitochondrial stressor and activates ampk, is it potentially going to inhibit hypertrophy, like I mean, are you? Are you potentially limiting the rate of muscle preservation or, potentially, growth? Show more

It's possible, I don't know. Yeah, yeah, it's an interesting, interesting thought that it's always crossed my mind. But well, all right, so we've got one more. Put you on the spot. Potentially the the most important, just in terms of quality of life, has been, you know, something I write about a lot in the book- or not a lot, but it's something I write about at the end of the book- which is the importance of emotional health, and I think that I just had never really considered that an important part of the equation, of this- you know longevity equation. Show more

Right, it didn't fit neatly into a box of, you know, delaying death from cardiovascular disease, cancer, neurodegenerative disease. It was a little amorphous and I, I think you know, I just had my own blind spot to it, which was ironic given that it was a part of my life that wasn't especially healthy. So I think now, having been through all I've been through and you know, sort of reflecting on what I've learned, I realize not that not only for me was this a very important thing, but I suspect it is for many people as well, if they will, you know, take the opportunity to to kind of probe that, yeah, it's, I mean, it's a, it's a huge umbrella that people definitely miss and it's just. It ultimately is the umbrella literally, of just how- I guess not literally, figuratively, but how we look at life and how it changes, how we look at exercise and how we perform and how we eat and how we, and not to mention the actual physical effect that we have of being in a good mood. Show more

And what are some things that you're doing today to improve that? Well, luckily, I'm kind of more in a maintenance mode now. I mean, I think I had to go through sort of the heavy, the heavy lifting, you know, six, seven, you know, or you know, three, four, five, six years ago. So so what I do today. I think is is much easier than what I did in the past, but I still work with a therapist once a week and I still practice something called dialectical behavioral therapy. So that's one form of therapy that I do and and that is just what it is right, it's like a practice. Show more

So it's sort of like saying, like we'll you know. You know, is it enough to know that a workout is important? No, you actually have to do the workout. So, similarly, it's not just enough, I think, to kind of show up for an hour a week to do the therapy. You have to be able to kind of take what you learn in that therapy and then put it into daily practice. And if you succeed, you note it, if you fail, you note it. But you're just constantly trying to to sort of get better. And DBT, or dialectical behavioral therapy, is a system that I really like and it really works for me and it works for many people. I've done a podcast on it, actually, which maybe we could link to. I think it's a. It's something I think a lot more people should know about. Yeah, I mean, my life changed for the better when therapy became a regular part of my life and I think there's a stigma that's attached to it and that needs to get broken down significantly, because people don't go to therapy until there's a cause for it or a reason for it and especially this day and age, not to, you know, go off on a tangent, but it's very. Show more

It's difficult to have that connection and sometimes therapy is the only place you actually get that connection, especially if you're not married, you don't have a spouse, you don't not going home to someone you know and you're just on your device all day. So I think that's really, really good advice and it's something that I would Echo. Show more

I think over the last five, six years I would have- I don't think I would have- casted judgment upon someone that was going to therapy, but I certainly wouldn't have looked at it with the same lens that I look at it now. So I think that's a great one. Yeah, well, we'll link out to those episodes down below. We'll also link out to your book. So, as always, keep it locked in here and, Dr Tia, thank you very much. Yeah, thanks, Tom. Show more