Keto vs. Carnivore, Hormonal Chaos from High Protein, the *Surprising* Truth About Cold Exposure, and Why Carbs Are CRUCIAL with Jay Feldman

Ben Greenfield [00:00:00]: My name is Ben Greenfield, and on this episode of the Ben Greenfield Life Podcast.

Jay Feldman [00:00:04]: In a long-term low carb diet, we still have elevated levels of these stress hormones. It's mostly in the form of glucagon. And then with cortisol, the levels aren't elevated at baseline, but in terms of a response to stress or response to exercise, let's say there's a greater increase in cortisol on a low carb diet versus a moderate or high carb diet. Long-term, these hormones act as a signal for our bodies to turn down their metabolic rate. Because they recognize that this is not sustainable. We have to continue to pull these resources from our stores. That's what the stress hormones do, and we're producing a lot of oxidative stress in the process. Even though the engine isn't working as well, the fuel isn't optimal, we're kind of forcing it anyway.

Jay Feldman [00:00:41]: And this has effects on the larger umbrella of our hormonal state, namely at our thyroid, we see a reduction in things like testosterone, reduction in the female reproductive hormones as well.

Ben Greenfield [00:00:52]: Fitness, nutrition, biohacking, longevity, life optimization, spirituality, and a whole lot more. Welcome to the Ben Greenfield Life Show. Are you ready to hack your life? Let's do this.

Ben Greenfield [00:01:16]: All right, folks, I have a podcast guest today who has some very interesting theories, often controversial, on things like hormesis and carbohydrates and energy. And I think he probably kind of has an opinion on a lot of these things that differs from what you hear in mainstream health and biohacking. His name is Jay Feldman. He's a health coach. He's an independent health researcher. He's the host of a podcast called the Energy Balance Podcast. He has degrees in neuroscience and exercise physiology from the University of Miami.

Ben Greenfield [00:01:53]: And kind of like me, he was really going to go to medical school, but decided to forego that after realizing the conventional medical approach might not be the best solution to the health problems that many of us face. And now he's helping people with his podcast and through different types of coaching and research that he does. And so he uses what is called the bioenergetic approach. The bioenergy energetic approach. So I'm gonna let Jay explain all of that to you as we jump in here. So, Jay, welcome to the show, man.

Jay Feldman [00:02:27]: Thanks for having me on again, Ben.

Ben Greenfield [00:02:28]: Yeah, yeah. I forget, how many years ago was it that we got on and talked a little bit about bioenergetics?

Jay Feldman [00:02:33]: Yeah, it must have been two years ago or so.

Ben Greenfield [00:02:35]: Yeah, yeah. And a lot has happened since then, obviously, I think the carnivore diet has probably blown up since the last time that we talked. Cause we didn't really get a chance to dive too much into that. I know it's probably something that's come across your radar, I would imagine, even though you're living under a rock down there in Ecuador. And I've also just been thinking a lot about some of the things that you talk about when it comes to hormesis and energy. And I think a good jumping off point here would be for you to describe what the bioenergetic model actually is, which I realized could be like a one hour response. But I might interrupt you here and there.

Jay Feldman [00:03:17]: Yeah, well, and I think it's a great starting place to kind of provide a contrast between this and most other views out there. So, and I've, and I've been there, you know, we were talking carnivore. I've been, you know, I've done low carb, I've done keto, I've done intermittent fasting. And you know, throughout the, my time doing that, didn't see the results I was expecting and you know, was always continuing to research and came across what's called the bioenergetic view of health, which is the idea that the energy that we produce inside of every cell, inside of the mitochondria, we normally consider that to be ATP, that that drives our health. And when we see degenerative states, chronic health conditions, symptoms, anything from insomnia to fatigue to fatty liver disease and on from there, you know, autoimmune issues, the whole spectrum, what happens is there's a breakdown in energy production and we're left with basically a lack of energy, a lack of ATP that causes degeneration and prevents us from effectively repairing every cell and tissue in our body and also prevents us from feeling our best. And so that, that's the approach with which I, I view health and you know, and digging into a whole, you know, the whole spectrum of, of health issues from neurodegenerative conditions to as I said, fatty liver disease, autoimmune conditions, hormonal imbalances, you see basically breakdowns in mitochondrial respiration, breakdowns in energy production. And so my focus is on how we fix that and how we maximize the cellular energy production so that we can maximize our health.

Ben Greenfield [00:04:46]: Okay, so let's, let's jump into some, some illustrative examples here. Let's take this idea and I think this would be a good way for you to explain how you view this whole idea of energy. Let's take something like hormesis, right? The whole, like, what doesn't kill you makes you stronger concept that a lot of people, especially in the longevity sector, are pursuing these days. Right? Like exposing yourself to mild amounts of oxidative stress, fasting, energy depletion, cold therapy, heat stress, you know, exercise stress, etc. Tell me about how, how hormesis kind of fits into the whole, the whole bioenergetics model that you just described.

Jay Feldman [00:05:31]: Yeah, so as you said, hormesis is built on the idea that, at least originally, it was something that was very toxic. Mercury, cadmium, ionizing radiation would cause damage and our bodies would respond to that damage and, you know, basically become stronger as long as it wasn't too much, as long as the dose was small enough. And then as a result, we would see an improvement in health. That's really where the idea started. And since then it's expanded to encapsulate a lot of different things that we do in our, you know, day to day lives that might cause stress, whether it's exercise or low carb diet or fasting or cold exposure. And we see similar pathways, just like with mercury, you see, you know, inhibition of mitochondrial respiration, you see an increase in oxidative stress, and you see the activation of defensive pathways. You know, when our bodies experience these things, they try to upregulate their antioxidant systems to prevent oxidative stress, and they try, they release a number of different hormones to deal with the stress that we're dealing with. And so the idea is that those things are beneficial because they cause a small amount of stress that our bodies are able to adapt to, and then we, you know, become healthier in the process.

Ben Greenfield [00:06:39]: Right. Sounds fantastic.

Jay Feldman [00:06:41]: It does, it does. The issue comes about when we start to get into the specifics. So as I was saying, there's actually no difference in terms of the stress and oxidative stress pathways between something like mercury, like a heavy metal that we know will kill you, and relatively small dose. Same thing with cigarette smoke. Same thing with very toxic byproducts from bacteria like lipopolysaccharide. Those share the same stress pathways with exercise or with fasting or with a low carb diet, and cold thermogenesis as well. And so what we might say is that, you know, I guess as a starting place that might want to lead us to have some caution about doing these things right, if they're activating the exact same pathways.

Ben Greenfield [00:07:24]: Well, when you say that they're activating the same pathways. For people who might not fully understand what that means, what those pathways are, what do you mean when you say like a cigarette would activate the same pathways as say, like fasting?

Jay Feldman [00:07:36]: Yeah. So you basically see the upregulation of various kind of defensive pathways. You see increased activity of AMP kinase. AMP kinase is produced when there's a lack of ATP. Basically, as ATP gets depleted, there's an increase in AMP and that increases AMP kinase. We see increases in a pathway called the NRF2 pathway, which is an antioxidant pathway as well. There's a whole kind of plethora of different pathways here that all activate in the same, you know, from these different stressors.

Jay Feldman [00:08:07]: And they all converge in that they're causing oxidative stress, they're causing some amount of damage. And then our, our bodies are responding to those. And so, for example, AMP kinase is something that will then, as a result of there not being enough energy, will then upregulate our energy production or will upregulate antioxidant systems. Another pathway gets activated is called the NAMPT pathway. And this gets activated when we have a lack of NAD, NAD+, which is one of the main molecules in, you know, inside of our cells, that helps us produce energy. And when that's low, we increase the activity of NAMPT, which is an enzyme that increases the production of NAD. So it's this, these universal pathways that happen anytime we're stressed, anytime we encounter something that's harmful, anytime that we are seeing basically damage to the cells. Those are, these are the kinds of pathways that we're talking about.

Ben Greenfield [00:08:58]: Okay, got it. Okay, keep going, go ahead.

Jay Feldman [00:09:00]: Well, so what people, you know, in the research, people will see that when we activate these kinds of pathways in different organisms, you know, rodent models and things like that, we see longevity. And so we assume that these pathways must be beneficial, they must be having long-term benefit in terms of longevity and health. But what happened, what's happened is that we've missed a huge part of the hormesis picture, which is everything that's happening outside of these pathways. So this is something that was delineated by Hans Selye quite a while back. And what he basically identified was that it's true that all of these different harmful aspects of our environment do share similar pathways. And this is called their stressor effects, basically the way that they deplete energy and cause oxidative stress and damage and inflammation. But they also have other effects that he called specific effects. And this is what differentiates something like exercise from something like arsenic.

Jay Feldman [00:09:50]: Right? Arsenic doesn't really have any beneficial specific effects. The main things that it does are basically impair mitochondrial function, block our ability to produce energy, you know, and cause some, some major damage. Whereas exercise, while it does cause similar effects to a, you know, to a small extent, it also has a number of other benefits. You know, we're increasing lymphatic flow and circulation and we have stimulation on the muscle fibers that will stimulate hypertrophy and, and there's, you know, neurological interactions there that will improve strength as well. So there's a number of other things that happen that we call the specific effects. And what Han Selye identified was that if the specific effects outweigh the stressor effects, we have a net benefit. So in the case of exercise, we can most of the time have a net benefit if we're doing a moderate amount of exercise. If we're excessively exercising.

Jay Feldman [00:10:40]: And we see this, you know, in the most extreme examples of, you know, marathoners for, you know, as a clear one, you tend to see some negative health effects. When we're doing too much exercise, we're incurring too much stress relative to the benefit of whatever it is that we're, that we're doing.

Ben Greenfield [00:10:53]: Right, the so called Goldilocks effect.

Jay Feldman [00:10:55]: Exactly. Yeah, exactly. But it's not just a matter of the dose makes the poison, because when we start to get into that conversation and this has happened in hormesis, people will start to say, well, the dose makes the poison for anything, right? With water, the right amount is good, too little is bad and too much is bad as well. And then they attribute that to stress. So they say, well, if it follows this dose response curve where a little bit is bad and too much is bad, but right in the Goldilocks zone is okay, it must be due to stress and the water must be having a stressful effect. It must be hormetic. And that's where it, we're getting our benefits from. So it's true there is a Goldilocks zone for all these things.

Jay Feldman [00:11:33]: There is a dose response curve. But in the research that has been taken to mean it's supportive of hormesis. One, I think we need to be really careful about that.

Ben Greenfield [00:11:41]: Okay, so something like exercise, I can do that, it causes stress, but there's side benefits. I get stronger, I might have improved VO2, max bone density, less frailty, better mobility, better mental health, improve sleep, etc. In the case of a cigarette, there's oxidative stress. But you know, the benefits might be, I don't know, a little bit of weight loss from the nicotine, some alertness, but the amount of toxic side effects outweigh the pros of that type of hormetic stressor. Now, what about when you get into something like say, fasting or carb restriction? Two things that you also mentioned is potential hormetic stressors.

Jay Feldman [00:12:22]: Yeah, and, and those I would say, fit in the exact same way. So there are benefits, of course, to low carb and, and ketogenic diets and fasting. There's also inherent negatives due to the stress that they cause. And it's not a small amount of stress either. You know, one thing that people will discuss when it comes to low carb diets is that, you know, over time you don't see a long term increase in cortisol. But what you do see, and we'll, you know, we can get into this in more detail because I do, you do still see long-term elevated stress. But even in the short term, what they call short term, you see elevated cortisol. That short term is normally about four weeks, four to six weeks even.

Jay Feldman [00:12:56]: There's very few things that we can do that cause so much stress that you'll have elevated cortisol for four to six weeks. So it's definitely not a small level of stress that we're talking about here.

Ben Greenfield [00:13:03]: Wait, when you say elevated cortisol for four to six weeks, that's from what?

Jay Feldman [00:13:07]: That's coming from a quote, normal diet or a non ketogenic diet. And then you go into a ketogenic diet.

Ben Greenfield [00:13:13]: Okay, so, so we're saying like the day that you start a ketogenic diet, cortisol would go up and stay up for four to six weeks. Like the day that you start, say, restricting carbohydrates.

Jay Feldman [00:13:24]: Right, right, exactly.

Ben Greenfield [00:13:25]: And is the cortisol going up? Because cortisol is one of the mechanisms via which your liver and your muscle might dump extra glucose into the bloodstream. You know, the same thing that people notice if they're wearing a continuous blood glucose monitor and wake up in the morning, get that morning cortisol awakening response and see the surging blood sugar. Is it similar but just going on for a longer period of time?

Jay Feldman [00:13:49]: Yeah, that's exactly what it is. The cortisol is responding to the lack of energy because there's the lack of carbohydrates and our bodies are shifting over fuel to what I would say is a suboptimal fuel in fat. And that lack of energy leads to basically all of our tissue saying alarm bells, like they're giving off alarm bells saying we need more energy. And that's where cortisol comes in to liberate glucose, increase gluconeogenesis, and also help to further shift us into fat burning so that we can conserve that glucose, since we're not getting very much. So that's exactly why it increases. And that happens anytime we're under stress. Right. Whether it's exercise or a psychological stressor, you know, an argument with somebody or something like that, or a ketogenic diet or mercury exposure. Whatever it is, cortisol is a pretty universal response there to a stressor.

Ben Greenfield [00:14:36]: Now, you just said that fat is a subpar fuel, and you don't hear that very often. A lot of people will say that fat is a slow burn fuel. You have more of it in your body than carbohydrates. A byproduct of fat metabolism might be the production of ketones, which could be used as a preferred fuel for the brain or the liver or the heart or the diaphragm. I mean, I could go on and on, but a lot of people say that fat, particularly in people who have followed a low carb diet for long enough to have become more adapted at burning fat, is a superior, not a subpar fuel. But you called it a subpar fuel.

Jay Feldman [00:15:14]: Yeah. And so the first thing I want to make sure that I clarify is that I'm not saying there's no place for consuming fat. I'm not saying there's no place for burning fat. As you said, it is kind of more of a low octane slow burn fuel, and that's perfect for tissues that don't need a lot of energy. So, for example, at rest, our muscles do really well burning fat. Right.

Jay Feldman [00:15:32]: And there's, I would say there's not really a negative effect to them. That's totally fine. But we see the issues with fat burning when we look at a place that has really high energy needs and is very sensitive to oxidative stress. And the brain is our best example of that. And so, as you said, when we're in a low carb state, we can be producing ketones and our brain will use those, but our brain can't use fatty acids for fuel, except for maybe less than half a percent of its total energy needs. For the most part, it really does not use any fat as a fuel, but it can use glucose or ketones. And the reason for that is exactly what I'm discussing is that there it is an inherently suboptimal fuel in terms of the amount of reactive oxygen species that get produced per ATP.

Jay Feldman [00:16:11]: So you have more oxidative stress per ATP produced.

Ben Greenfield [00:16:14]: When you burn fat, you create more oxidative stress per the amount of ATP that you produce.

Jay Feldman [00:16:21]: Yeah. And again, this is fine if we're talking in the muscles at rest, because those reactive oxygen species kind of slow the speed of the engine a little bit. They act as an inherent brake on the system to make sure we're not producing energy too quickly.

Ben Greenfield [00:16:35]: Right. We're under excess oxidative stress, so don't produce too much energy. Kind of very similar to how, like a lot of lactic acid accumulated during exercise would put the brakes on muscle contraction due to the pH of the muscle tissue.

Jay Feldman [00:16:47]: Exactly. Yeah. Yeah, exactly. And so that's. That's fine if we don't need a lot of energy, but in the brain, that can't fly because it's very sensitive to oxidative stress and it needs to produce a lot of energy. And so the reason for this boils down to some biochemistry that I'm happy to dig into as deep as you'd like.

Jay Feldman [00:17:04]: But essentially, there's a ratio of FADH2 and NADH that gets produced when we're burning different substrates. And when we produce carbohydrates, that ratio is much lower, meaning that there's much more NADH produced and much less FADH2.

Ben Greenfield [00:17:19]: You said when we produce carbohydrates. You mean when we consume carbohydrates?

Jay Feldman [00:17:22]: Yeah, when we burn.

Ben Greenfield [00:17:23]: Okay, when we burn carbs, we do what now?

Jay Feldman [00:17:26]: There is a higher amount of NADH and a lower amount of FADH2 that gets produced when we burn fat. The opposite is the case. There's about 250% difference in terms of how much FADH2 gets produced relative to NADH. So we have opposite. An opposite effect. And the result of that is that when we go down to the electron transport chain where we produce ATP, basically things get slowed down when we're burning fat, and there's a lot more reactive oxygen species that get produced. And so this is just the biochemical mechanism that is responsible for the difference in reactive oxygen species production per ATP in either case.

Ben Greenfield [00:18:05]: Okay, and why would that not be okay when. When you look at fats producing more oxidative stress. I mean, and the reason I ask is I would hypothesize that there might be some sort of a mechanism that would allow for reduction of that oxidative stress or that you know, fat still might produce some more slow burning fuel or that the ketones that you are getting from the fats would be enough to go around since the brain needs kind of trace amounts of glucose relative to say, all the skeletal muscle in the body anyway. So explain to me why it would actually be bad that fat would cause this issue.

Jay Feldman [00:18:42]: So in the brain it's not so much of an issue. The brain will mostly be using ketones. It'll still be using, you know, 30 to 40% glucose, but for the rest of the body, most of it will be using fat. We don't produce that many ketones just in, in general, when we're on a ketogenic diet, we really only produce enough mostly for the brain. The rest of the body is almost running entirely on fat. And so when we're then faced with any increased energy demands, we're more prone to having lack of ATP, which as you said, you know, if there's lack of ATP and an increase in oxidative stress, won't the body respond in some way? And it does. And this is where those hormetic mechanisms come in.

Jay Feldman [00:19:19]: We activate these backup pathways. We produce stress hormones like glucagon, adrenaline and cortisol. And those stimulate the tissues to make more energy despite oxidative stress. They basically say this is necessary, this is top priority, make the energy anyway. And in the short term that's not a big deal. But what we want, you know, what we're concerned with is the long term effects there. Because what we see is in a long-term low carb diet, we still have elevated levels of these stress hormones. It's mostly in the form of glucagon.

Jay Feldman [00:19:48]: And then with cortisol, the levels aren't elevated at baseline, but the, in terms of a response to stress or response to exercise, let's say, there's a greater increase in cortisol on a low carb diet versus a moderate or high carb diet. And so as a result of that, again in the moment, no big deal, we produce energy either way and, and we're fine. There's a little bit of damage as a byproduct. But long term, these hormones acts as, act as a signal for our bodies to turn down their metabolic rate because they recognize that this is not sustainable. We have to continue to pull these resources from our stores. That's what the stress hormones do. And we're producing a lot of oxidative stress in the process. So we're, even though the engine isn't working as well, the fuel isn't optimal, we're kind of forcing it anyway.

Jay Feldman [00:20:29]: And this has effects on kind of the larger umbrella of our hormonal state, namely at our thyroid and also in terms of the reproductive hormones. So what we see as a result here, let's just say, of elevated glucagon, is you're going to see a reduction in the conversion from the inactive thyroid hormone T4 to the active thyroid hormone T3. And what that does is it slows our metabolic rate down. Since T3 and our thyroid hormones in general are the main ones that keep our metabolic rate up, we see a reduction in T3 which lowers metabolic rate.

Ben Greenfield [00:21:00]: Right. So, absence of adequate glucose is putting the brakes on T4 to active T3 conversion.

Jay Feldman [00:21:05]: Exactly, yeah. And as a downstream effect of that, we then see lower production of the reproductive hormones as well, which depend on T3 and are directly impaired by hormones like cortisol. So we see a reduction in things like testosterone reduction in the female reproductive hormones as well. And this is something that's seen in, like in epilepsy patients who are, you know, have to be on a ketogenic diet long term, and the women have incredibly high rates of amenorrhea and, you know, kind of reproductive issues on a ketogenic diet due to the disruption in those hormones.

Ben Greenfield [00:21:40]: Right. And do you think the hormonal disruption is due to so much cortisol being produced that there's fewer building blocks for hormones like estrogen or testosterone? Or is there a direct impact on things like follicle-stimulating hormone and luteinizing hormone, FSH and LH? Meaning do they require some type of glucose similar to the T4 to T3 conversion to adequately produce something like testosterone? Or is it more just that too much is going, too much of the building blocks is going towards cortisol?

Jay Feldman [00:22:10]: It's not even the building blocks or even a need for glucose. It's more of the hormones. So cortisol on its own will inhibit GnRH, which is gonadotropin releasing hormone, which then will reduce FSH and LH. So then you're going to get a downstream reduction.

Ben Greenfield [00:22:24]: So it's upstream negative feedback brought on by cortisol?

Jay Feldman [00:22:26]: And at the, at the actual locations as well. So at the testes, for example, if you introduce cortisol, it'll lower testosterone production. And if you take away T3, it'll impair testosterone production since T3 is necessary for the, the activity of the STAR protein, which allows for the uptake of cholesterol into the mitochondria. And then produces steroid hormones like testosterone or progesterone.

Ben Greenfield [00:22:49]: Right. And just so I understand, when we're talking about this, how low carb a scenario are we talking? Because there's different definitions as, you know, for some people, low carb. I mean, some people define me as low carb, and I have anywhere from about 250 to 350 grams of carbs per day. Other people would define low carb as like 40 grams or more of a strict keto approach. But how much are we talking here as far as the body's needs and how low an amount of carbohydrate intake would cause some of the issues you're talking about?

Jay Feldman [00:23:20]: Yeah, well. And most in the health world these days would. Would say that you're having a very high carbohydrate diet. You know, I know.

Ben Greenfield [00:23:26]: Even. Even though for me, that's less than 30% of my total calorie intake.

Jay Feldman [00:23:29]: Right, right. Yeah, normally I would say So I recommend 40% on the low end of carbs for most people. It's. When we're looking in the literature, 200 grams tends to be a good low end. You know, typically when you're going below 200, you really start to see these effects. Above 200, it's a lot more muddy. But of course, that's gonna depend also on our individual needs. How active are we? How much muscle mass do we have? Where's our metabolic rate? Are we, you know, have we dealt with the effects of aging over a long time, and we're dealing with a low thyroid activity?

Jay Feldman [00:23:58]: You know, then those needs would be a little, you know, then I think 200 would maybe be a good minimum at that point. But I think for, you know, you or me, our needs are going to be considerably higher.

Ben Greenfield [00:24:12]: Yeah. And how much of this, because you mentioned research, how much of this has been looked at in research? Like, have they taken low carb versus high carb? And look at that cortisol, looked at thyroid, looked at hormones, or looked at. What was the other one? Oxidation. Have any of those studies actually been done?

Jay Feldman [00:24:34]: Yeah, so there's a lot less research than we'd hope. And a lot of the research is not particularly long term. You know, they'll do a diet for a lot of times, it'd be a week. But there's enough studies that they'll do at least, you know, four weeks or so, which some people would argue is still not enough. And so the number of studies that go into this longer term are few and far between. But they are there and they are notable. So in the research what we clearly see is low T3 and this is even on people who are averaging four years on a ketogenic diet. There's a great study that was looked at in support of the lipid energy model, the lean mass hyper responder phenotype, that whole area of research, and they were looking at women who were on a ketogenic diet for around four years and found that they had particularly low T3 and also elevated reverse T3.

Jay Feldman [00:25:19]: Not by the kind of mainstream ranges, but I mean I think most people would agree that, that those values were definitely not ideal. You know, the free T3 was like 2.5. They put them on a carbohydrate containing diet for three weeks and their T3 came up to I want to say 3.5, which is a pretty significant increase. They went back on the ketogenic diet and the T3 went right back down to I believe right around the same 2.5, maybe 2.6 or something. So we do have, and these aren't people who are already on a ketogenic diet for the long term. There are others looking at epilepsy patients showing a general trend toward lower T3 and elevated TSH. As I was mentioning, the studies on epilepsy patients showing issues with the female reproductive hormones. So those are some of the clear ones as far as the stress hormones go, elevated glucagon is seen pretty universally on low carb and ketogenic diets. At least at the four week mark and typically beyond that as well.

Ben Greenfield [00:26:17]: And remind people who aren't familiar with it what glucagon is doing.

Jay Feldman [00:26:19]: So glucagon is kind of our first stress hormone. We've got a few primary ones. I mean, there's a bunch. But the main ones I would focus on are glucagon, adrenaline and cortisol. And they kind of increase sequentially. So in the most minor stress you'll see elevated glucagon. In a little bit more intense stress, you'll see epinephrine, which is adrenaline. And a little bit more intense and you'll see cortisol. And so in the studies looking at the stress hormones in, on people on a very low carb or ketogenic diet, elevated cortisol is seen at least through the first month, sometimes beyond that as well, elevated glucagon is seen past that point.

Jay Feldman [00:26:54]: And then the other thing that's seen as well is that even though the cortisol levels aren't always elevated past that point. In people who are on a low carb diet for that long or for longer, what they see is that there can be normal cortisol levels, but inside the tissues, there's actually a reduced clearance of cortisol and an increased regeneration of cortisol. These are based on effects at enzymes like 11 beta-HSD and 5-alpha reductase. 5-beta reductase. And so effects on these enzymes actually can cause high cortisol in the tissues. Even if your blood cortisol looks normal, which a lot of people will say, you know, initially I saw a high cortisol and low carb, and then over time it went back to normal, but you still could have high tissue cortisol.

Ben Greenfield [00:27:35]: It's a blood cortisol measurement, and blood does not necessarily reflect tissue cortisol.

Jay Feldman [00:27:39]: Right, right. You can look at the urinary metabolites of how much cortisol is getting cleared as like an indirect test.

Ben Greenfield [00:27:45]: Like a Dutch test. Yeah, that's a really good point. I do recommend the Dutch test quite a bit because a lot of times blood cortisol values can be normal, but that doesn't mean the metabolites aren't either building up or being cleared very quickly, which was. Which is what a urine test can tell you.

Jay Feldman [00:28:00]: Yeah. And salivary as well. I've seen people with normal blood cortisol but very elevated salivary cortisol. Especially because blood is normally done once a day and our cortisol is a natural rhythm and that rhythm can be interfered with. And so you might have normal cortisol in the morning, but it's really elevated later in the day. And you don't see that if you only get a blood test in the morning.

Ben Greenfield [00:28:19]: Now, what would you say to people who would say that constant access to carbohydrates and a relative stabilization of cortisol is almost a little bit of an ancestral mismatch, because human beings for thousands of years have had periods of time where they might have experienced famine, fasting, hunger, needed to push through without a lot of fuel on board while, say, hunting or gathering. And that by simply saying, well, let's just give ourselves ad libitum carb access throughout the day so that our cortisol stays low and we're just kind of, you know, fat and happy, so to speak, really is not the way that human beings have operated from an ancestral standpoint. And this would be a relatively new phenomenon to propose, just eating carbs 365 days a year, 24/7 without having periods of say, carb depletion or fasting.

Jay Feldman [00:29:17]: So it's true that we're always going to be encountering stress and that stress can come in different forms, whether it is fasting or a lack of carbs or the stress that a lot of us are facing modern day. So I don't think it's something where even if we're eating a high carb diet, we're free of stress, which is just one thing to consider. But another is, you know, we can kind of, we can guess as to what exactly we were eating, what exactly we were doing. However, there is, if we look at A, certain native cultures currently that are eating very high carb diets and B, we look at some different evidence in terms of what was going on ancestrally. It might not be so far-fetched to have a very high carb diet even in a natural environment. So for one thing, to consider humans, for most of our evolution and pre-evolution, the evolution of primates prior to us and other hominids and everything, we were in pretty tropical climates. We only really left the tropics about 40,000 years ago or so. And of course in the tropics, there's year round fruit, different fruits that are available all the time.

Jay Feldman [00:30:25]: And so the idea that fruit would have only been seasonal would only really be true for a small blip in terms of our evolutionary lineage. And we can look now at are other, you know, ape counterparts that are currently living in those areas and they eat a diet that's 60 plus percent fruit most of the time. You know, chimpanzees.

Ben Greenfield [00:30:45]: Wouldn't some people say that their guts are developed in such a way that they can transform a lot of the fruits that they're eating, a lot of those fibers, into fatty acids due to different gut composition and butyric?

Jay Feldman [00:30:56]: Some of the primates. Yes, but so when we look at the, what's called the expensive tissue hypothesis, which looks at the relationship between the gut, the size of the large intestine, small intestine and brain size in primates, and then also diet, what they find is a couple of things. One is as fruit increases in the diet, you see an increase in intelligence and you also see a decrease in the size of the colon of the large intestine. And on the flip side, as more fibrous foods are consumed, you see a decrease in terms of intelligence and a larger large intestine, which is where we're converting those fibers to the short chain fatty acids. So if you take a gorilla for example, they ferment a lot of food. They eat very fibrous food and they produce a lot of fatty acids. So even though their diet is coming from a decent amount of carbohydrate, they are still using a lot of fat that's coming from their gut. But with chimps and bonobos, that happens much less.

Jay Feldman [00:31:47]: The large intestines are much smaller, much more similar to ours, and they're absorbing the fruits up in the small intestine, and actually getting the carbohydrates.

Ben Greenfield [00:31:55]: Right. They're actually getting more glucose than fatty acids compared to a gorilla.

Jay Feldman [00:31:58]: Yes. Yeah, glucose and fructose too.

Ben Greenfield [00:32:01]: Okay, yeah, glucose and fructose. So what about these people, like, forget her name, Mary somebody, who used coconut oil and the ketogenic diet to help out with Alzheimer's and dementia. And you see this repeat a lot. I think Dale Bredesen talks about it sometimes as well. This idea of a high fat diet being almost very healing for the nervous system and stabilizing for those with brain issues. Alzheimer's, other forms of dementia, concussion, TBI, etc. Like, it seems as though limiting carbohydrates assists those type of cases.

Jay Feldman [00:32:36]: Yeah, it does. And I think there's really good reason for it. And I think we can get those same benefits without the negatives, which is the same way, same thing, I would say, whether we're talking obesity or diabetes and low carb diets. And so, and they're very similar because a lot of people will identify that insulin resistance in the brain is a primary driver of these issues like Alzheimer's, and they'll call it type 3 diabetes. And so what's happening in that state is our bodies are having trouble using the carbohydrates, the glucose effectively. They're getting to the mitochondria, and the mitochondria are blocked by other things, and so they're not effectively using the glucose. Well, in the brain, that's a huge problem because if they're not using the glucose well, and we're on a high carb diet, so there's not really any ketones, you're left without any good fuel. And so you might still use the glucose, but you just convert it to lactate, which is really inefficient. You're not getting very much ATP, and you end up with a lot of oxidative stress, a lot of issues.

Jay Feldman [00:33:27]: So one way that these, that a low carb or ketogenic diet provides relief in the state of something like Alzheimer's, is providing an alternate fuel that we can still use even if we're having trouble using glucose. So if we're dealing with insulin resistance, let's say just in the brain and it's not using the glucose well, it can still take up those ketones and use those well, and now you have adequate energy production. The second reason, which has been shown in different models as well, is carbohydrates can cause problems in the gut when we have an imbalanced microbiome.

Ben Greenfield [00:33:58]: Right. Something like small intestine bacterial overgrowth or something like that.

Jay Feldman [00:34:03]: Exactly. Yeah, exactly. And when that happens, instead of us digesting and breaking down those carbohydrates, a large portion goes to the bacteria, and especially the ones that are higher up and overgrown. They're not just producing short chain fatty acids, but they're producing different things that are relatively toxic to us. One of the most well known is called lipopolysaccharide or endotoxin. And that alone is, can be or is considered to be responsible or a primary driver for insulin resistance. And you see what's called metabolic endotoxemia, which is just generally elevated levels of endotoxin in everything from heart disease to diabetes. And so that's the second main area that we would get benefit when it comes to a low carb diet is we're not feeding these bacteria, we're not producing the endotoxin. Things are a lot calmer in the gut.

Jay Feldman [00:34:48]: And endotoxin also is able to get into the brain, cross the blood brain barrier, and cause insulin resistance and oxidative stress there. So by alleviating this massive, massive kind of toxic stressor from our bodies, we can also have major benefits.

Ben Greenfield [00:35:02]: Right. So it's kind of back to Hans Selye's idea that you have to step back and look at is the amount of stress caused by restriction or additional of a certain hormetic stressor paired with enough pros to be able to justify it. Even if it's short term, you have something like Alzheimer's, dementia, SIBO, etc. So you're not painting with a broad brush and saying, just eat as many carbohydrates as you want. No matter what you're saying, generally, try to get about 40% of your diet from carbohydrates if you don't want the cortisol stress, potential impact on the endocrine system, thyroid, etc., that could come with excessive carbohydrate restriction.

Jay Feldman [00:35:43]: Yeah. Yeah, exactly. And I'm also not saying all carbs are equal either. And that we should all be, you know, eating bread and Coca Cola as our carb sources.

Ben Greenfield [00:35:52]: Sure. You're not. You're not a seco guy. You're not. You're on the, I suppose, I guess would be something more like, what's a guy, Layne Norton, who's just, you know, I think that's kind of his take on this.

Ben Greenfield [00:36:02]: Right. That macros are most important, but the composition of them is not as important.

Jay Feldman [00:36:07]: Only in so much as they cause you to eat more, you know.

Ben Greenfield [00:36:10]: Right, right. So what does your diet look like? I'm just curious, like, how you apply this, like, in the streets. Like how you actually diet and how you exercise on an average day.

Jay Feldman [00:36:19]: Yeah, I can walk through that. And also how I apply it to people who I work with and also people who are dealing with things like insulin resistance, because there's a lot of great information on that. But essentially, I would say that 40% is kind of the low end when it comes to carbohydrates of what I recommend.

Ben Greenfield [00:36:35]: And is there a high end, by the way?

Jay Feldman [00:36:37]: Normally, like 65 or so would probably be the high end.

Ben Greenfield [00:36:41]: And is it because of the nutrient density of fruits or their digestibility or the fiber content or the satiating effect that you recommend fruits as the primary source?

Jay Feldman [00:36:49]: So I would say the primary reasons are digestibility, polyphenols, and nutrient content. And that nutrient content includes the carbohydrates, which I think are very beneficial. So, yeah, all of those things. And we can talk about, you know, in the research issue that you see issues with pure fructose feeding, which is really irrelevant because we never get anything with pure fructose, and that causes a lot of endotoxin production. We can talk about issues with sugar, sweetened beverages, and pure table sugar, but if you look at research on fruit, it's pretty universally all beneficial, even in people who are dealing with diabetes and fatty liver disease. And really, the same applies for fruit juice as well.

Ben Greenfield [00:37:28]: I saw that study a few weeks ago, by the way. No difference between whole fruit and fruit juice when it comes to the glycemic index. And in fact, I reported this on a podcast, blending fruit lowers the glycemic index of the fruit, paradoxically, because apparently you're blending all the seeds and skins and making them more bioavailable. And so it made me feel pretty good about the blueberry huckleberry in my smoothie kick I've been on lately.

Jay Feldman [00:37:52]: Nice. Nice. Yeah, I think fruit juice is definitely, has definitely gotten a bad rap, but I don't think it's deserved.

Ben Greenfield [00:38:00]: Okay, so your, back to your diet or the diet that you're using with your clients. A lot of fruit and around 40 to 60% carbohydrate intake.

Jay Feldman [00:38:08]: Yeah. And so fruit, other sources would be honey and maple syrup which are very high in polyphenols. And the maple syrup has some nutrients in there as well. And then I do think that depending on digestibility and this can vary based on the individual, we can bring in root vegetables and some easily digestible or well processed grains like white rice. On the root vegetable side, this can be again well cooked and processed potatoes, sweet potatoes, carrots, parsnips, things like that.

Ben Greenfield [00:38:35]: Okay, got it. And then, what are you doing about the proteins and the fats? Where do those come in and what are the sources for something like that?

Jay Feldman [00:38:41]: Yeah, so I think this is an area where you know, very much align with the low carb crowd and that I think, you know, our quote, animal-based protein sources are generally best when it comes to nutrient and fat composition. So red meat is a great source there. Low fat seafood that's low in PFA is, is great as well. And very nutrient dense dairy for people who do well on it. Of course, some people don't digest it well. Eggs. And then, you know, some, I think some other non-ruminant meat can be okay if it's lean. I think we do have to be really careful when it comes to chicken and pork that they can be really high in omega-6s if they're fed foods that are really high in omega-6.

Ben Greenfield [00:39:20]: Two perfect examples along with shellfish and fish higher up in the food chain of you are what you eat. Ate.

Jay Feldman [00:39:25]: Yeah, exactly, exactly.

Ben Greenfield [00:39:27]: Okay, now, now if exercise is so stressful that it could cause this law of diminishing returns when it comes to the excess cortisol, potential increase in inflammation, oxidation, etc. How does your exercise protocol look or the exercise protocol you're using with your clients?

Jay Feldman [00:39:44]: Yeah, so our, you know, the general capacity for dealing with the stressor is going to vary based on the individual. So on one end, we could have someone who has chronic fatigue or was really, you know, dealing with severe metabolic syndrome and they could go for a walk for a mile and have a lot of inflammation and feel pretty bad after it. Maybe they don't sleep as well or their energy crashes. Whereas someone else who is on the other side of the spectrum might not even notice any effect from doing that. So I think to exercise is also something we need to tailor to the individual. And generally, as long as we're moving away from being sedentary, that's, I would say, the most important thing that's gonna make by far and away the biggest difference. And that's seen in the research as well. When we look at metabolic syndrome, weight loss, if we can just not be sedentary, that by far and away accounts for the most benefits.

Jay Feldman [00:40:32]: And then I think as we can improve our stress tolerance, bringing in some occasional, you know, medium or higher intensity exercise can be great. My suggestion in general is to find something that you enjoy, whether it's, you know, a sport. People are playing a lot of pickleball these days, but it could be swimming or tennis or basketball, you know, pickup basketball, whatever it is. Weightlifting as well is an option. You know, it can really be anything, as long as we're getting some level of activity in and we're, we're walking enough, we're not sedentary. That's my, that's kind of my baseline recommendation that I think, you know, we can get it to minutia. And the minutia definitely can matter at the ends, you know, when we want to go from 90% to 95% of. In terms of improving athletics or body composition or muscle mass.

Jay Feldman [00:41:16]: But for most people, I would say that's. Those are the most important things.

Ben Greenfield [00:41:20]: What about like heat stress, cold stress, things like that?

Jay Feldman [00:41:23]: It kind of depends on what the outcome is that we're looking for. When we look at the. What kinds of things will stimulate muscle growth, for example, there's a lot of different. There's been a lot of different theories out there. And one of them is that if we just introduce enough stress to the muscle, that will cause the growth of the muscle fibers and that'll increase strength and hypertrophy. And most of the research outside does not support that. And instead what it shows is that there is an increase in muscle synthesis, muscle protein synthesis, in response to a stressor, like some version of, let's say, heat stress or cold stress or introducing lactate or something like that. It will increase muscle protein synthesis, but it doesn't increase net muscle protein synthesis.

Jay Feldman [00:42:06]: So what that means is that there's muscle breakdown when we introduce these stressors, and then the muscle protein synthesis comes in to repair that muscle breakdown. When it comes to the things that actually increase net protein synthesis that'll help with muscle building and strength, I would say what seems in the research to be the most really the only thing that matters, I would say, is getting enough muscular tension, enough tension on the muscle fibers. And, you know, there's a lot of ways we can do that, and some of these interventions that you're mentioning might help us do that. Right. If we're doing occlusion training, for example, that might be something that helps us get to that level of muscle fiber recruitment and activity and tension, but it's not independently beneficial, I would say.

Ben Greenfield [00:42:50]: What about heat stress and cold stress? Like that? That's what I was curious about. Like, people are doing sauna, cryotherapy, cold baths. Is that a part of your protocol or are you recommending that to people at all?

Jay Feldman [00:42:59]: Yeah. So when it comes to heat, like, let's say sauna, I think there can be a lot of benefits. I think there's a lot of benefits to infrared light when it comes to mitochondrial function and red light when it comes to mitochondrial function. There's benefits to heat in that it increases circulation, helps with lymphatic flow, helps with, you know, sweating, which helps with de detoxification processes. So there's a lot of benefits to it. But if we do it long enough, it will definitely induce more stress than those benefits. So it's one of those things where several minutes, 10, maybe 15 minutes in a sauna that's moderately hot, I think is fine. I think when we're going beyond that, we're inducing more of the stress side and that's going to start outweighing the benefits.

Jay Feldman [00:43:37]: So that's how I would think of the heat side of things. When it comes to cold, I don't think cold, in my view, as far as the specific effects, I don't see that much in the way of cold other than improved tolerance to cold. So when we get more and more exposed to cold, we get more tolerant of cold and it doesn't affect us as much. But I don't see much in the way of, at least I would say, good support for cold doing anything other than causing a good amount of stress.

Ben Greenfield [00:44:08]: What about blood glucose management and insulin sensitivity with cold?

Jay Feldman [00:44:12]: I think that those are going to be mediated by the stress. When we're like, there's a big increase in, in stress hormones and calorie expenditure when we're exposed to cold, which is the same as if we were exercising. Right. We use a lot of fuel and both of those will help use the glucose that's available. You know, it'll kind of dispose of that glucose.

Ben Greenfield [00:44:31]: Yeah, I mean, it plummets my blood glucose for hours after I do it.

Jay Feldman [00:44:35]: Yeah, yeah. Which I'm. I don't know if you've measured like stress responses after, but I would assume that with that glucose going as low as it is, we probably have elevated stress for a while too.

Ben Greenfield [00:44:45]: Well, short term, big stress response. And I mean, when I do my cortisol measurements, even though I've been doing a lot more blood these days, my cortisol levels are fine. But the longest I'll get in an ice bath unless there's some type of throw health out the window competition between me and my friends is about two minutes. Basically I get up within 20 minutes of waking. I get in 35 degrees for a couple of minutes. And I can tell you that I don't even think about a cup of coffee after doing that.

Jay Feldman [00:45:13]: And a lot of people are using coffee in the same way. Right. They're drinking coffee right when they wake up and they're getting the same stress effect. And so ideally I would say, you know, we don't want to get, be getting all that stress. And that is, it is worth mentioning with the cold. That is a, you know, there are some benefits in terms of mood for sure. Again, I think a lot of them are stress mediated.

Ben Greenfield [00:45:31]: It feels different than a cup of coffee. It's more alertness than like jitteriness or anxiety, you know, especially with too much coffee intake. But I'm curious with all of this though. You know, you start to describe what you do with your clients. But I want to know about Jay. Like what's Jay do when he wakes up? What do you have for breakfast? When do you do exercise? You know, do you have lunch? What's going on the rest of the day? How are you weaving in this, you know, this non exercise activity? Walk me through a day with Jay.

Jay Feldman [00:45:55]: I wake up and have breakfast maybe 30 to 45 minutes after, you know, wake up, take the dogs out, and then prepare breakfast. And so it might be, you know, it's always some balance of carbs, fat and protein. My macronutrient breakdown is about 20% protein and then 40 carbs and 40 fat.

Ben Greenfield [00:46:13]: Yeah. Not a whole lot of protein. So you're probably. When people say you should be getting like close to a gram a pound, you'd be a little bit under that. Most likely.

Jay Feldman [00:46:21]: Yeah. My recommendation is 0.6 to 0.8 grams per pound.

Ben Greenfield [00:46:24]: Okay. Yeah, that's, that's, that's somewhat low.

Jay Feldman [00:46:27]: Yeah. It's coming from research. Menel Henselman's has some great studies on this looking at resistance training athletes and people who are actually, it's not just sedentary average individuals and basically beyond about 0.7 grams per pound, there was no benefit in terms of protein synthesis, muscle protein synthesis.

Ben Greenfield [00:46:48]: I think some of that has to be couched in the actual population study because I think with very active weight training individuals, it has been shown to be a little bit higher as far as the net gains where protein intake kind of tapers off.

Jay Feldman [00:47:02]: We'll have to take a look at that study because from what I remember, it was looking at people who are in that category of individuals that are training quite a bit.

Ben Greenfield [00:47:12]: Okay, so trained individuals, 0.6 to 0.8 grams per pound. And you're starting off today with protein, fats, carbs.

Jay Feldman [00:47:20]: Yeah, so I might have plantains or fruit smoothie. And then, you know, I might have eggs or some pastured bacon or beef bacon with that. Sometimes I'll do like a chicken hash with eggs on it and the hash will have some potatoes. And I do, I will have coffee at that point, but I make sure the coffee is not fasted on an empty stomach to help avoid the stress, because as long as the coffee's with fuel, you don't get that same stress effect. So that's breakfast and most of the time after that it's, you know, I'm up in the office until lunch. And lunch is similar in terms of breakdown, you know, so it's going to be some protein source. Could be beef, lamb, lean chicken.

Jay Feldman [00:47:59]: And you know, it could just be fruit, dried fruit on the side, maybe juice. Sometimes it'll be potatoes or rice.

Ben Greenfield [00:48:07]: And are you active at all in between breakfast and lunch? You stop in moving, standing workstation, things like that.

Jay Feldman [00:48:13]: I've got a sit-stand workstation. I wish that my work didn't keep me glued to a computer as much as it does. But for the mornings, normally I'm pretty glued here. But I will have to get a walking setup like you have.

Ben Greenfield [00:48:27]: Yeah, it's nice. Saves my butt on many days where I'm not able to do much except walk on the treadmill and talk with people like you. Okay, so you got lunch and then what happens after lunch?

Jay Feldman [00:48:39]: Yeah, so again, I would say most days between. So I would call that first lunch. I normally have four meals. And so between first and second lunch, I'm normally back in the office for, you know, a couple more hours and then I'll have a second meal that's or second lunch that's basically the same as the first and again same Thing, sit, stand, desk. But not much beyond that. And then normally after that second lunch is when I'll either take. I mean, I might do a bit more work and then I'll either take the dogs for a walk or play with them out in the yard. I do go to the gym for weightlifting once a week. And then once or twice a week I do MMA training or Muay Thai kickboxing, those kinds of things.

Ben Greenfield [00:49:15]: So if you only go to the gym once a week to lift weights, how long are you there?

Jay Feldman [00:49:19]: About an hour.

Ben Greenfield [00:49:20]: Okay. Yeah, so. So not too much. I'm assuming you're going pretty heavy, though, and going with a lot of that time under tension that you mentioned.

Jay Feldman [00:49:26]: Yeah, yeah. I'm definitely trying to get the. That stimulus for sure. And I. It's a full body workout. It's not, I would say it's not optimized for building as much muscle or strength as possible. That's. My goals are kind of maintenance on that front and maybe a little bit of growth, but more so my, on my athletic ventures, I enjoy mixed martial arts and, and Muay Thai kickboxing, those kinds of things a lot more.

Jay Feldman [00:49:48]: And so that's more my focus. And honestly, in the past when I. Cause I, you know, there was a point where I was about 205 pounds and really lean, I had a lot more muscle mass than I do now, and I felt like it really slowed me down when it came to those other athletic goals.

Ben Greenfield [00:50:03]: Yeah. Do you take any supplements?

Jay Feldman [00:50:05]: Nothing daily, but as needed, I'll use, you know, maybe some. Some B vitamins. Just if I feel like I need a bit of a boost or. Yeah, I mean, it's really pretty rare that I'm using too much.

Ben Greenfield [00:50:19]: Yeah, yeah. And for you, you know, being a guy who's as immersed in the science of this as you are, are you also doing tests? Like, have you done blood testing? Do you find things that you want to tweak and adjust, or are your levels pretty good across the board from the protocol you just described?

Jay Feldman [00:50:33]: There's always small things I'm adjusting. You know, I'm looking at vitamin D and just, you know, I'll make a point to get outside a bit more. I try to eat my meals outside the lunches. Outside. Yeah, there's. There's always small things I'm tweaking, but it's. They're generally pretty small.

Jay Feldman [00:50:47]: Yeah.

Ben Greenfield [00:50:47]: Okay, got it. What do you think about the carnivore diet? Because a lot of People will say, well, you could use that meat and break it down and produce adequate glucose through gluconeogenesis. You don't have to have a bunch of carbs with that diet. But what's your take on carnivore?

Jay Feldman [00:51:01]: Between carnivore and keto, I would actually say I think keto is better in terms of macro breakdown.

Ben Greenfield [00:51:06]: But when you say better, you mean like, healthier?

Jay Feldman [00:51:08]: Yeah, yeah. Healthier. Like, I think that it's better to rely more on fat than it is to rely more on protein's conversion to glucose, and the main reason for that is basically twofold. When we're, when we've shifted fully into ketosis, we're running a lot more on fat. And everything's kind of running on kind of like a lower steady state when it comes to a really high protein diet or a higher protein diet, if it's carnivore and it's not high enough fat, if it's not carnivore keto, if it's just kind of carnivore, you tend to see much higher increases in stress hormones because of that constant conversion from glucose to. Or, sorry, from protein or amino acids to glucose.

Jay Feldman [00:51:34]: Since you're running more on glucose, but you don't have that glucose available, and that tends to increase things like glucagon and cortisol more. And I would say, you know, then has a worse effect when we're looking at the thyroid, when we're looking at reproductive function. I think the benefit of a carnivore is some people are super sensitive to different plant foods.

Ben Greenfield [00:52:06]: Autoimmune issues. You mean the reason that people like Jordan and Mikhaila Peterson would have used a carnivore diet?

Jay Feldman [00:52:12]: Exactly. And so that's, I think, a place where carnivore could benefit over keto. But I'd still prefer if you're doing carnivore, it's keto carnivore. It's still high fat and more moderate protein. But it. Otherwise, it's still. So you still have the same benefits, right? You still have the same provision of alternate fuel instead of glucose, at least a lot more fat. You still have the benefit of relief from the gut.

Jay Feldman [00:52:31]: In most cases, you're still gonna have way less endotoxin. However, another issue with very high protein is there is, in many people, limitations in protein digestion. And that same protein can then travel down the intestines and feed bacteria and create some really toxic products as well. And so that would. And that has been shown to happen, you know. Someone's consuming more protein that they can adequately digest. So that is, you know, an issue there. But again has the same benefits for the most part in terms of the gut and providing an alternate fuel, but the same long-term issues.

Jay Feldman [00:53:02]: And you know, most of the people I'm working with are very much, you know, very into their health and they've been. They've done keto, they've done carnivore. And initially they normally experience those benefits and those benefits have really outweighed the negatives and the drawbacks. But over time they start to notice their sleep deteriorate, they start to notice testosterone decrease or libido decrease. You know, on the female side, cycles getting irregular, they tend to notice the energy start to slump. So I really see that play out where we're having these short term benefits and then start to see those costs catch up with us.

Ben Greenfield [00:53:35]: What about these guys like, like, you know, Dr. Sean Baker, who just seemed like an absolute, you know, beast? You know, I realize I say that, you know, kind of like the liver king, you don't know, you know, what kind of things are also going into the system to help them keep up. But it seems like some people are, are thriving on a carnivore diet or at least staying pretty strong and seem to have a decent amount of energy.

Jay Feldman [00:53:58]: It's great that they're doing well. I, it's so hard to know what's going on under the surface for somebody and I'm, you know, not trying to say like anyone's lying if they say that they are doing well and they're not. I know for me, I probably would have said I felt really great when I was on low carb and I think I didn't know what, like I would say that. I definitely didn't. Looking back, you know, it's, yeah, it's hard to say what someone else might be experiencing. I think also some people are really resilient and you know, some people are able to. We were talking earlier about excess exercise and marathoners and negative cardiovascular and gut effects, but some people are able to do incredible amounts of exercise and still remain very healthy. So I think some people are naturally more resilient. It's hard to say. It's all kind of conjecture at this point.

Ben Greenfield [00:54:46]: It is interesting. I think the highest consuming population that I know of, energy drinks and stimulants, is the low carb keto crowd. And I suspect that part of it could be right because they have that long-term cortisol exposure and eventual energy depletion and a lowering of ATP production via some of the pathways that you've described. So you see a lot of those people, you know, sucking down a lot of energy drinks, a lot of stimulants, a lot of nootropics, and in many cases it's because they're afraid to have an apple and some blueberries in the morning.

Jay Feldman [00:55:21]: Yeah, yeah. And I think a lot of times too kind of making up for some stress effects with high dose sodium, you know, the electrolyte packets, things like that as well.

Ben Greenfield [00:55:30]: Yeah, yeah, you see that too. Well, my approach is, you know, like I said, I eat 250, 350 grams of carbs per day. I don't like to eat a lot of carbs, typically until the evening, mostly because it's my most socially flexible meal. And the meal where there probably is going to be things like, you know, bread, pasta, higher carb intake, desserts, etc. I usually have, like I said, also, especially in the summertime, berries with my morning smoothie, sometimes a little bit of fruit with lunch. But I think my main takeaway from a lot of what we've been talking about is that, you know, as you implied, Jay, early on, stress is stress is stress. And while I don't necessarily think that people need to forego things like heat stress, cold thermogenesis, you know, paying attention to how many carbs that they eat, exercise, etc., I think they do need to take into consideration how much stress they're piling on their bodies by doing yet the next thing that is supposedly the beneficial hormetic stressor. And once you pile up like 10 hormetic stressors in a day, then you can run into some pretty significant biochemical issues.

Ben Greenfield [00:56:38]: And I also think that, you know, when it comes to, to the idea of how many carbs you're going to take in, I think you also made a really good point that sometimes if you do have gut issues or you do have autoimmune issues, or you do have something like Alzheimer's, you may need to be careful with the type and extent of the carbohydrates that you're consuming. But that doesn't necessarily mean that carbs are the villain that many in the keto low carb carnivore community have pinned them to be.

Jay Feldman [00:57:15]: Yeah, and we don't have to be stuck in that state either. We can improve our ability to utilize the carbs coming in by addressing possible nutrient deficiencies, fixing the gut health.

Ben Greenfield [00:57:24]: It'd be like short, short term healing stints, you mean?

Jay Feldman [00:57:26]: Yeah. And there, you know, I think a lot of this kind of has gotten swept under the rug in the low carb crowds. But there's quite a few studies, I mean, on hundreds and hundreds of people using very low fat diets, you know, in, in insulin resistance and diabetes and getting people off of insulin. I mean, it's not this idea that the only solution is cutting carbs. I think is, is missing some of the, the larger picture of what's really going on. And, and hopefully someone listening to this takes this as an opportunity to, you know, if you are in the low carb sphere, consider are you, are you health? Like, are you fully healthy? Are you optimally healthy? How's your sleep? How's your libido? How's your stress? How's your mood? How's your energy? And maybe this could be an opportunity to test something else out.

Ben Greenfield [00:58:13]: Right? Understand that carbs aren't going to kill you. And then, man, I wish they could do a CGM like device that would also do glucagon, cortisol and stress hormones, you know, adrenaline, norepinephrine, etc. That would be very useful because then you could just know, hey, you know, and I realize HRV could be a corollary for that. And maybe that is a good idea, right? Like if you're tracking HRV and you're listening in, maybe try adding a little bit more carbohydrates, see what happens to hrv. And that could be a pretty good indicator right there. What do you think, Jay?

Jay Feldman [00:58:42]: Yeah, I wonder, I wonder how, like if it's going to change by the hour enough.

Ben Greenfield [00:58:48]: Yeah, it'd be a long-term improvement with a chronic increase in carbohydrate intake, I think.

Jay Feldman [00:58:52]: Yeah, yeah, I think so. Yeah. And I've seen that for sure.

Ben Greenfield [00:58:55]: Well, for those of you listening, I'm going to put all the show notes at bengreenfieldlife.com/feldman2. Feldman, the number 2. Because this is the second time Jay has been on the podcast. I'll link to the first discussion that we had in the science of his bioenergetic hypothesis, also in the show notes. And if you have questions, comments, feedback, I realize some of this stuff can be confusing for so many people who might think keto low carb, carnivore is the way to go. And now they hear fruits are okay or carbs are okay. So I think that the main thing to understand is another friend of mine who's a nutritionist named Joel Greene says, you know, just be careful of baby talk in nutrition. It's not all good, all bad, black and white. There's a lot of subtle nuances.

Ben Greenfield [00:59:37]: And I think that as you've done a really good job outlining here, Jay, stress is a major component of those subtle nuances. So again, it's going to be bengreenfieldlife.com/feldman2. Feldman, the number 2. Jay, thanks so much for coming on, man.

Jay Feldman [00:59:52]: Yeah, thanks for having me. And if listeners want a good starting place, I have a free Energy Balance food guide they can download if they head to jayfeldmanwellness.com/guide and that might be a good starting place for figuring out what kind of carbs might be good ones to begin with and go from there.

Ben Greenfield [01:00:08]: Jayfeldenwellness.com/guide. Cool. I'll put that in the show notes too. Jay, thanks so much, man. I always learn a lot when I'm talking with you.

Jay Feldman [01:00:14]: Yeah, thanks for having me, Ben. That was a great chat.

Ben Greenfield [01:00:16]: Alright. folks, I'm Ben Greenfield, along with Jay Feldman and Jay Feldman Wellness signing out. Have an incredible week.

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