Geoff

Professor Keith Baar, welcome to the H.V.M.N. Headquarters. Thank you for coming by.

Keith B.

Thank you, it's great to be here, it's a nice facility.

Geoff

Yeah, thank you. I mean, you had to trek in through some rain, it's raining pretty badly outside in San Francisco, so thank you for making the trip. So, to provide context for our listeners, we had first met at a human performance related summit back a few months ago. And you gave an interesting talk around some of the work you're doing around human performance, increasing performance, increasing resilience, and obviously all that work that you do at UC Davis relates to a lot of what we're interested in, both from a company but also as a community here in our podcast space.

So I think there's a lot of ways we can start and highlight topics. I know you've done work with them mTOR, ketogenic diet, tendons, PPAR-delta agonists. But perhaps to start the conversation, a ketogenic diet is something that we talked a lot about on the program, so it might be a nice entry point into the discussion. Can you describe your work with the ketogenic diet, how'd you get first interested in the space, but also maybe just to open up the opportunity to talk about how dud you even become a physiology researcher and a biochemist, and all of that.

Keith B.

Okay. So for me, the trip to physiology started in performance. So I was a strength and conditioning coach with the Michigan Football Team, so I was working with high performance athletes for a long period of time. And so, the idea there was that, we would put all of these different guys on these different training programs that were fairly similar. They all lifted a lot of weight, they'd all be working really, really hard, high intensity training to failure. And then some of them would grow huge and strong and build muscle like there they were just inflating themselves with a pump, and other people would work just as hard, maybe even harder and you wouldn't see any changes. And I really wanted to understand, kind of why or how the muscle grew in response to these trainings. And so, that was my PhD. And so I had gone away, I had originally gone to Berkeley and then came back to the University of Illinois, the Medical Center there, and I did my PhD. And was lucky enough to discover kind of this central regulator of growth was activated by exercise. So, when you did resistance exercise you turned on mTOR complex one, and if you turned on mTOR complex one more, you will get more muscle growth than if you turned it on less.

And so that was really the foray into starting to understand kind of how you could target one single molecule with all of these other things that you're doing. And then the neat thing comes when you've identified a molecule that's kind at the base of kind of affecting what you want to do. And now what you can do is, you can say how can I affect that using diet, or how can I affect that using other things. And so our interest then became, okay can we manipulate this with diet. And sure enough, the leucine rich protein, what leucine does is it activates mTOR complex one, so it makes sense that when you do exercise with leucine rich protein, you get a bigger muscle than if you didn't have the leucine protein. And the real crux of that, that's really important is, when you understand the molecular mechanism of how you turn on mTOR, leucine does it differently than the exercise. And so, when you do the two things together, you actually get an additive effect.

So what leucine does is, is it moves an inhibitor away from the mTOR complex. And what resistance exercise does, is it moves a different inhibitor, and so what leucine does, is it brings mTOR to its activator. And what resistance exercise does is, it removes the inhibitor from that activator. So you've got mTOR moved to the right spot now, and the activators, the thing that prevents it from working is gone from the resistance exercise, those two things working together you get this huge response. Whereas, if you only have one, you only get part of the response. And so, those types of things really brought this lesson of, look, if you understand what you're trying to do, you can figure out all kinds of different ways to do that. And then, some of them are gonna add together to produce more, and some of them are going to work in the same way and you're just gonna get the same response.

Geoff

Right. It's kind of like almost engineering an outcome that you want right? You found this mechanism, it's like the underlying mechanism, that you think is very, very important. How do we manipulate it? And one of the most common shorthands we always bring up in conversations is mTOR. Can we break that down for the audience that might not be as familiar with mammalian target of rapamycin.

Keith B.

Right. So this is this really interesting protein complex, and that's the key component of it. So what mTOR is, it's an enzyme, and what it does is it adds phosphates on to other proteins, so it's a protein kinase. And so, what it is, is it's the core of a lot of signaling pathways. And mTOR exists in two different complexes. mTOR complex one, is one that's important for protein synthesis and protein breakdown. And what it does is, it interacts with a couple of other proteins which all it does is decide which proteins it can phosphorylate, which ones it can add phosphates to. And so in mTOR complex one, it's together with a protein called raptor, which allows it to target proteins, that are important in growth. In the other complex, mTOR complex two, it's together with a protein that's called rictor. The difference between the raptor and the rictor, is in the name. So, rapamycin is where raptor gets its name. So rapamycin sensitive complex with TOR, and rictor is rapamycin insensitive complex of TOR. So, we say mTOR complex one is the first target of rapamycin. If you treat it for long enough, it blocks both of them and that's some of the problems with rapamycin. So it's basically this protein in mTOR that is in these complexes that allow growth, allow protein synthesis, allow protein degradation, so that you can have a dynamic growth situation.

Geoff

Right. So, one thing that most people associate with mTOR is a nutrient sensing pathway. So can you unpack, when people hear mTOR it's usually nutrient sensing. Can you help glue these concepts together?

Keith B.

Yeah, so there's two ways that mTOR is regulated by nutrients. The most obvious way is that, when there's leucine rich protein, leucine actually can bind to a specific protein within the cell. It's in all cells, it's called sestrin. There's a bunch of different flavors of sestrin. And what it does, is it actually removes the brakes. And there's a complex process by how this happens. But what happens when leucine binds to sestrin, is this series of events starts, that ends up with mTOR moving to its activator, it's a small protein called Rab. So when the leucine comes into the cell, it binds to sestrin, and that releases all of this inhibition, and mTOR moves to its activator. And so, that's leucine rich protein will do it.

The other way that mTOR is inactivated, is actually by metabolic stress. And so, specifically classically it had been this idea that AMP-kinase can inhibit mTOR. And the AMP-kinase is activated when the ATP ratio or the amount of ATP in the cell goes down, and the amount of AMP goes up. So in situations where there's low glucose, where there's fasting, you'll get an activation of the AMP kinase, and that is thought to inhibit mTOR through one of the upstream inhibitors of mTOR. AMP kinase can phosphorylate this protein and keep it together with that little protein Rab, and it prevents mTOR from being activated. So it keeps Rab inactive. So mTOR is kind of the hub of nutrient sensing, because amino acids can come in and these carbohydrates, fasting can come in to give us a sense as to whether it's a time to grow, so let's turn on mTOR because there's lots of leucine rich protein, or whether it's a time where we need to restrict growth because we're in a caloric deficit.

That became really a focus when I came back to my undergraduate Institute at Michigan, and I did a postdoc there. And the guy that I worked with is one of the smartest people literally in the world. He does everything from engineer little things to diagnose whether you have a concussion. He engineered the first type of muscle, he engineered heart ... all of these incredible things. He's an engineer, he builds stuff. He's built something that's in every automatic transmission car, so he doesn't really have to work, he does it because he likes to work. So, this is the kind of person that I was working with at Michigan. And he really instilled in me this idea that, look there, an engineer, you just build it. A physiologist, you want to understand how everything works. And those two things working together can create something that you wouldn't imagine from the physiology.

So the engineer just wants it to work. He doesn't care how it works. The physiology only cares how it works. And now, when you put those things together, you get these things that work, you have no idea why. But then if you actually know what you're trying to target in physiology, now the engineering says, well what if we did this combination of different things, and what if we used this different technique to do it. And it really shifts how you think about it. And so, when we started understanding those things and we'd look in the literature and mTOR complex one is central to cancer, and it's central to growth, and that's essentially why it's important for muscle growth, is because it's important for growth in general.

But with growth comes this idea that, if I'm the biggest of the species I'm gonna live the least amount of time. The example I always give my students is, if you have two dogs and one's a little thing that we don't really call a dog, and one's a big dog, that big dog's gonna have a shorter lifespan. And really, one of the only differences between them is their IGF signaling which goes through mTOR, which causes your Great Dane's to be much taller, much bigger. And it also presumably is contributing to this decrease in lifespan. And so when you look at drugs that increase lifespan, the number one drug that increases lifespan is rapamycin which blocks mTOR. And so now you've got this really interesting thing, and that's where we had stepped into this ketogenic diet idea. Because at Davis, we have probably the best lifespan sciences in mice, a guy named John Ramsey, who is a colleague of mine, and we have Geno Cortopassi. And the two of them had been working on dietary or nutritional, or metabolic things that increased lifespan.

So they had started looking at this molecule called P66SHC, which Italian group had shown could increase lifespan. And what they found is that the kind of the genetic profile that you get, is an increase in fat oxidation, it's something that's similar to what you would see if you shifted more towards fat utilization. And so, the big study that they did and they included me on, was this study that what we did is, we kind of clamped the number of calories that they could have, because some of the diets are more palatable than others. And then what we did is, we manipulated the macronutrients. And so, this is again John Ramsey does this probably better than anybody in the world, where he can go in and he feeds the control diet. We then gave a low carbohydrate diet, so it was still high in protein. And so, in mice that's important, because mice are very good at converting amino acids into sugars. So they were not ketogenic at that point.

Geoff

And then the control mimicked the standard Western diet.

Keith B.

The standard western diet, the ADA type diet.

Geoff

Okay.

Keith B.

And then what you had as a third group, it was a lower protein to induce ketogenesis. So it was a no carbohydrate, it was about 10% protein, the rest was fatty acids. And so, what John found in the lifespan studies, is that just going low carbohydrate increased lifespan, it was nonsignificant, but it was about 6%. And then when you did the low carbohydrate ketogenic diet, what you found was that the lifespan increased by 13% over the control. And so that was an exciting finding, because that's similar to what you would see with something like rapamycin which is a drug that has really been popularized as this possible thing that could increase lifespan in a variety of different organisms, humans, dogs, all kinds of things. And so for us, that's real interesting because it could very well be that what the ketogenic diet is doing is, it's decreasing mTOR complex one activity in the body, and that's why the diet is working. And so, what our role on that paper was to do, is to actually go in and measure that. And so what we did is, we started measuring markers of mTOR activity in the liver and other tissues.

And sure enough, mTOR activity was down. And so that was really interesting and exciting. And the way that we're thinking of going forward with that is to say, is the increase in lifespan the result of the ability to inhibit baseline mTOR activity. So, mTOR is really important for cancer growth. The mice in our study, eight out of the 10 control mice died of cancer, in the ketogenic diet there were only two out of 10 of the mice that we went in and quantified how they died. Only two of them died from cancer. So again, especially in the sense of the cancer component of it, it had a huge effect.

Geoff

One thing that that was interesting or perhaps nuance that not a lot of observers would understand, is that mTOR can be tissue specific. And I believe that you discovered different tissue specificity on the ketogenic diet.

Keith B.

And that's huge for us as well, because basically one of the things that's good about exercise, as I'd showing in my PhD, if I want to grow my muscle I need to turn on mTOR in my muscle. But when I do exercise to activate mTOR in my muscle, it's got a metabolic consequence. So I'm using all of this energy in order to do my exercise. And what that does is, that depletes energy from other places. So if I look in the liver, mTOR activity is lower in the liver. And that's important, because it's going to have consequences for glucose production, it's gonna have other consequences in the body.

If I look in the fat mTOR content, mTOR activity is lower. And then if I look in other tissues throughout the body, what I'd see is that by putting that metabolic stress of the exercise, what I've done is I've actually suppressed that mTOR in those areas. And then in the brain, one of the things that we think is happening is that, you get an increase in this this protein BDNF or brain derived neurotrophic factor, and downstream of that can be mTOR as well. So some of the protein synthesis necessary for learning and memory we think is potentially activated by mTOR or mTOR is involved in that process. And so, what you can get is you can get positive effects on the muscle for growth, you can have affects in the liver where regionally you've inhibited mTOR and that's got a positive effect on liver metabolism. But then because you also can stimulate this in the brain, you've also got the potential to activate something that's going to improve learning and memory in the brain.

Geoff

Right.

Keith B.

So by doing this regionally, that's really important. And that's why we try and do it with diet and not with a drug like rapamycin.

Geoff

Which hits everything universally.

Keith B.

Exactly. And so, we know that when you treat individuals with rapamycin, it increases the lifespan, it also causes insulin resistance, it also causes muscle wasting, it also impairs muscle regeneration, because we know there is an absolute necessity for mTOR to fix damaged muscle.

Geoff

Right.

Keith B.

So if we injured a muscle by doing eccentric loading, the only way that that muscle regenerates is if it has proper mTOR activity.

Geoff

Right. I think a lot of the popular discussion with mTOR for longevity, seems to be fairly simple. Where it's one dimensional, on or off switch, and we want to be inhibiting as much as possible. It's kind of like the first double headline that most people I would say in the biohacking space or just the general lay interested folk looking to optimize longevity. It's like okay, minimize mTOR. I think it's worth a nuanced discussion around okay, we want tissue specificity, because I think as referencing to your football days, we want to be gaining lean muscle tissue, and you want to be activating mTOR for those use cases. And for different other regions like the liver, you probably want to be minimizing that. So given that there's this nuance of regional difference, could you expand upon ... I guess explore the nuance a little bit, like what regions would we want to be amping up, or ramping down mTOR? And it sounds like a drug like rapamycin is not tissue specific, so just hits everything.

Keith B.

Exactly.

Geoff

Which could be reasonable, but maybe not ideal. And it sounds like for diet, this is much more tissue specific.

Keith B.

Right.

Geoff

And I guess the natural question is, after that, are there tissue specific compounds or drugs that one can come up with?

Keith B.

So we start with the basics. So obviously for us, mTOR activity in muscle is gonna be paramount because in humans ... so all of the rapamycin data is in model organisms because obviously it takes a long time to get that date in humans. But the interesting thing with model organisms is that the food is right there, they don't have much activity, they don't have a bathtub that they have to get in and out of. When you go to humans, the number one correlate with longevity is actually muscle to mass, it's actually strength. So, if you have greater muscle mass and strength you're gonna live longer. And so, that's a really important nuance between the model organisms where everything is kind of there, and their longevity is not determined by their ability to do their activities of daily living, because they-

Geoff

I want to interject. Do you have a hypothesis on why lean muscle mass is the highest correlate?

Keith B.

So, it contributes in a number of different ways, and one of them is just the strength to survive. There's a second that we really think is important, which is if you're older and you're strong and you're robust, people always come up to you, "Oh, you look great!", and you get all this positive reinforcement. And the only way to actually stay robust, is to actually go out and be in an environment where you're out in a social environment-

Geoff

Social component, a little factor there.

Keith B.

There's a huge social component to it. There's a huge functional component of being able to ... you're not gonna fall as much, you're not gonna have all of those secondary problems. But it's also, the tertiary thing is that, you have this huge muscle mass and all of that muscle mass is going to use [crosstalk 00:21:17]. It's gonna be a glucose of it's gonna be a fatty acid sync. If you have healthy muscle that maintains mitochondrial function, those mitochondria are actually gonna produce things that actually are really essential to inhibit the production of a neurotoxin in the brain, so there's this beautiful pathway that's around this amino acid degradation product called kynurenine.

And kynurenine is really interesting because it circulates in the blood, and what happens is it goes up to the brain, it goes across the blood brain barrier, and then it can be broken down into quinolinic acid. And quinolinic acid is a neurotoxin. Well, when you exercise you have a high amount of mitochondrial mass, you produce an enzyme called the kynurenine amino transferase. And what it does, is it cuts kynurenine into kynurenic acid. And now it's a charged molecule and it can't get across the blood brain barrier.

And so, this is supposed to be one of the ways that exercise inhibits depression. This is supposed to be one of the ways that exercise inhibits the progression of neurodegenerative diseases like Alzheimer's or other things. We talked earlier about this idea that it produces BDNF, and that's one component of it, so you're producing a positive thing. And you're also getting rid of this negative thing. And so that's really an important function of muscle, especially muscle that is rich in mitochondria, it's rich in metabolic activity. And so all of those things. So you have this metabolic sync where you can take up fatty acids and you can use them as a fuel, you can take up glucose and use it as a fuel. You can break down things that are gonna be neurotoxic. You can do your activities of daily living.

Muscle is playing this immense rolling in our longevity and our well being, especially our health span. And so, that's really what we think is key. And so, when we look at something like rapamycin, which can extend lifespan, but it can cause muscle to slowly decline, your muscle mass and strength to slowly decline, we actually think that, yeah you're gonna be alive, but you're not gonna be enjoying life.

Geoff

Right, your health span.

Keith B.

Your health span is going to be-

Geoff

Might be compromised.

Keith B.

Yeah, severely compromised. And I always give the example of my neighbor. My neighbor is 102 years old now, and she, up until a year and a half or two years ago, she was out, every day she'd go for her walks. She would go down to the senior center down a couple blocks away. She would do yoga, she would do all this strengthening work. She's totally fit. Her brain works beautifully, everything works beautifully. And that's exactly what you want to be able to do. Relative to her size, she's super strong. She used to complain that the yoga instructor at the senior center made him get down on the ground to do these things, and the ground was all dirty. But she would have to then get herself up so she would have to use her musculature to get herself up. And so it kept training her, it kept doing those things all throughout this extensive life. She's still going at 102, and she's out plugging away. That's exactly what muscle mass does, it gives you this energetic sync, but it gives you the ability to do all these things. And everybody who sees here, talks to her and she gets this positive reinforcement. All of those things together, make it so that you feel young, you behave much more like a young person.

Geoff

Yeah, that makes sense. And then, I gotta put you on a little bit of tension there, but going back to the tissue specificity and why diet or nutrition is more tissue specific, and then if that is the case, can we develop drug like compounds, or just external molecules to be, you know, the better version of rapamycin that's tissue specific?

Keith B.

Yeah. So the tissue specificity is really important for this, and this is why we think that where rapamycin breaks down, is what I want to be able to do is, I want to decrease baseline mTOR activity, but I still want to be able to stimulate it when I need to regenerate my muscle. I still want to be able to stimulate it if I want to grow my muscle. I still want to be able to stimulate it if I have an infection. Because rapamycin was originally developed as a drug for anti-kidney rejection. So when you got a kidney transplant, what rapamycin does is mTOr is absolutely essential for your immune function. So, by taking rapamycin you decrease your immune function, and so when you have a kidney transplant, you're not gonna reject the kidney. And so that's where it developed, and that's why it was really a powerful tool. But if you are going through day to day life and you can't mount an immune response, now you're at greater risk of having other complications. If you can't grow your muscle, if you can't regenerate your muscle, now you're at the risk of going into a decline. So, if you can't have tissue specific activation or inhibition, and you don't have the dynamic range of the signal, that's where the problem comes in.

So what happens as we begin to age, we begin to get a little obese, we begin to develop these things. Baseline inflammation goes up. So mTOR activity actually in the muscle, if we look at it over time, it actually rises at baseline. And what the ketogenic diet does, it keeps the baseline down. So if through age we're getting this slow inflammatory other signals that are causing a baseline increase in mTOR, now when we actually go to do something that stimulates it, like we need to regenerate a muscle, now we don't have the dynamic range anymore.

Geoff

So the delta is bigger, and that's going to give an actual better response. Like this mTOR fatigue or something.

Keith B.

So what happens is the signal is already kind of on, so it's harder to turn it on, and it's harder to get the increase in activity that we need in order to have all of these functions.

Geoff

Kind of like the story with insulin resistance where you just have a higher baseline.

Keith B.

It's exactly the same. So, basically what we think is happening, is your baseline mTOR activity is going up, and just like insulin resistance when you just don't have the dynamic range to then respond when there's a glucose challenge, or when there's an immune challenge, or when there's all these other challenges. And so what we think is happening with these diets is that, you're decreasing the baseline. So that when you have a stimulus, your dynamic range is much higher. And so when you have an infection, if you've been on a diet where it's lowered mTOR activity throughout the body, now your immune system has this huge dynamic range that it can use to generate the immune response. When you got and you've exercised, now you've got this huge dynamic range.

And so, that's why we think that this tissue specificity as to ... and it's really more about keeping the baseline low, maintaining the dynamic range and then by keeping the baseline low, all those other tissues that really shouldn't activate mTOR except in the case when you get a cancer, now those are always low anyway. And so you're not getting that response in those tissues, but you still have the dynamic range in the tissues were you need that response.

Geoff

Right, as opposed to rapamycin, which would suppress or blunt any sort of dynamic range?

Keith B.

Exactly. I was on the train today with somebody who was telling me about a daughter who was born and had to have a heart transplant at a month. And then you have to be on all these antirejection drugs. And so, what the result is, is she's very, very small. She doesn't grow normally.

Geoff

That make sense.

Keith B.

And as a result, because all of these drugs are blocking the whole system, so she's not able to grow taller. Because the way that you grow taller is, that you have these signals through growth hormone IGF1, that increase collagen synthesis, which pushes your bone plates apart and you grow taller. And so, all of those responses are inhibited. And so for her, that's an extreme example of what happens when you don't have these tissue specific effects. You just don't get the same growth, you don't have the same ability to thrive.

Geoff

Right. So how would we go about engineering tissue specific molecules or interventions. I mean, I think that's a natural engineering question. Like okay, we have some understanding of the nuances here. This is probably in line with your work. How do we play this, so we optimize the benefits without the downsides?

Keith B.

So as far as drug targeting it becomes a little bit difficult. But what we would do is, we would do something that we would do in exercise, okay. So what we do, and this is something the British cycling or sky cycling now has done for years. And what it is, is you target by using exercise as a targeting device. So if I were to take any supplement right now, sitting here, sitting on the train on the way down here, not really having had any activity, it would go to my liver, it would circulate around a little bit. If there's no response, it's going to increase blood flow to any tissue. So if there's no insulin response ... because one of the things insulin does is, it shunts blood to specific tissues, so that you can target nutrients. So if I don't have anything like that, I just take the supplement and I sit here. It's gonna get to my liver, it's not really gonna go to many other places.

Geoff

And broken down and-

Keith B.

And it's gonna get broken down and shuttled out. Now if I do an exercise session, and I take it right afterwards, and I've got lots of blood flow going to the muscles they just worked, what you've basically done is you've taken an envelope that you've put into the mail, and you've put an address on it. So same nutrients, same supplement, but now by using blood flow that I've done, I've targeted to the muscles I want to target by using exercise, now everything that I just took in is going to go to the place that I want it to go.

And the way that to go yeah okay the way that sky cycling has done this, and other cycling and British cycling, and a number of other groups, they want to get rid of the upper body. They want to maintain legs, because that increases power to weight ratio. And so the way that you do that is, you go on a very low calorie diet, and all of the calories are taking in around your activity. And so, we've done this with USA track and field as well, basically if you're a track athlete you need to have leg strength, but you're just carrying the upper body. And yeah, it's important for balance, but it doesn't need to be very big for balance. And so what we try and do, and especially with sprinters who've had to, you know, the US doesn't support their Olympic athletes overly well, so they have to go out and get a job modeling. If you're gonna be a model, if you have a big upper body it makes you a better model, it makes you more attractive. And so they build these upper bodies that they then have to carry on the track.

And so what we do is, we give them a very low caloric diet. We have them take all of their calories in around their exercise, and then we give them all calories that are gonna be leucine rich proteins, so that it's gonna be targeted to the muscle that we want to maintain. And so, in that way you can ... you know, I know sky cycling, they maintained leg strength, leg size, in an individual who had a 3 to 4 kilo loss in upper body mass. So you waste the upper body mass, because you don't need it, and then you maintain the lower body mass by using the exercise as a way to target the nutrients.

It's the same thing that Lance Armstrong did during his cancer rehab. So, he was getting chemotherapy, he was taking in calories, and he was cycling through this. So as he was cycling, he had been a triathlete, he had been a guy with big upper body, big back, big shoulders. And then as he's cycling with chemotherapy, the chemotherapy and the nutrients are all getting targeted to his muscles of his legs, so he maintains. The chemotherapy targeted him and he lost a huge amount of upper body mass. And it was a lot of muscle mass that he lost. And so that increases power to weight ratio and gave them this great advantage. So as far as whether you can get in and target a specific drug to have a signal in it, which takes it to the liver, which takes it to the ... well it's easy to get it to the liver, but it takes it to the muscle, or it takes it to another area, that's a little bit difficult. But we can do that using our activity.

Geoff

Yeah, I think that makes sense. I think that's a lot of nuance, that's something that we've been thinking about and talking about recently on the podcast and in the community is that, there's like a few different levers. There's the timing of consumption, the macronutrient ratio of that consumption, and then I think about the two main levers. I think most people in an exercise or other activity that you do, I think most people talk about them in silos. I think that's something that was actually brought up at the conference. This strength and conditioning coach, hangs out in the strength and conditioning coach department. The nutritionist at his department, the skills coach is at his department, they don't talk. And what you're saying here, is basically you're combining the exercise with the timing of nutrition, which targets exactly where you want to target.

Keith B.

And it's not that there's a window where you have to get in within a certain amount of time. Because the window is quite big and it's quite open. But what you do have to do is, you have to get it to where you want it to go. I think the best example of this is a study that Lou Van Lou has been doing in Holland and Belgium. So he's a colleague of mine who studies protein turnover, and he's one of the best in the world at measuring protein turnover in muscle. He's done it in brain, he's done it in all kinds of tissues. And what he did is, he took people who they come into the hospital in coma. And what he does, is he just electrically stimulates, slightly electrically stimulates one leg. And he can maintain the mass in that leg, while the other leg atrophies completely. That's how little activity, so it's not a ton of activity, he's just stimulating it, he's just giving it enough of the stimulus so this contractile, so that you get a little bit more blood flow that you can get some of these signals that we still don't really understand. But just by doing that, now that leg can stay at the same size, while the rest of the body's going away, because they're in a coma.

Geoff

Which is I guess, a good hope for folks that have more of a sedentary lifestyle, that you need just only a bit.

Keith B.

Yeah, it really is just a little bit. And all your exercise really does, is it helps, as this is what Luke always says, it's what his mom used to day, is you go and you exercise because you are what you eat. And when you exercise you actually become more of what you eat. So that means that you incorporate more of the things you eat, into you as a person. And so, one of the big things that exercise does, is it actually drives nutrients and it drives the ability to take up those nutrients and use them to build and turn over the proteins within your body.

Geoff

So you've touched upon and you mentioned collagen, ligaments, tendons as an area of interest that you've been looking at. Obviously ACL injuries, these are one of the most common sports injuries in America, in the world. Curious to hear about your work there, and other practical tips that has come out of your work that folks can get some tips or lessons from.

Keith B.

It's a really interesting area, because probably even 10 years ago people just thought it was a completely inert tissue, your tendons were these bands on the end of your muscle, and they didn't really do anything. Your ligaments were just sitting there and the only time anybody thought about them was when they broke. And so, what we've really been noticing and learning, is that they're completely dynamic tissues. And the way that we got into this is that, when I was working with my postdoctoral mentor, Bob Dennis, who's that really smart guy I talked about earlier, we were engineering these muscles. So we were engineering little muscles, and this was part of a project for the military, where we were trying to create these brain ... basically you could control the muscle, and the muscle would be a motor, and that you could use that motor to do whatever, so it could last forever because it could sell regenerate, it had all these capacities that a normal muscle does.

But what we'd do, is every time we put onto onto a machine, it would pull off, because the interface between the muscle and the machine was always the weak spot. So we had to figure out how the body did that, so we had to understand what a tendon was and how a tendon was working. And so what we had learned in that early work that I did with Ellen Arruda at University of Michigan, is that our tendons are these really cool tissues that aren't just an inner band, they actually as you go along them towards the bone, they become stiffer. As you go along them towards the muscle, they become less stiff. And so that's perfect for what its role is, is to connect two tissues that are very different in their mechanics.

Then we started trying to engineer these tendons and ligaments. We engineered with one of the PhD students here...she engineered the first tendon. And then we've since done some really cool work, where I have a colleague Liam Grover in the UK who's at Birmingham, and he's 6'10" himself, 6'11'' I think. So he's this huge guy, I met him at a conference just because, oh my god, who the hell is that over there, because he's huge. But he's a bone engineer. So that's kind of fitting for somebody who had to build a lot of bone, he makes bone. So, what we do is combined his technology for making these little bones with our engineered tendon, and now we engineer a ligament which is kind of bone ligament bone.

And when we were starting to play with these things, what we would notice is that we could manipulate things, and they would grow bigger and stronger, they would get more collagen, they would be really dynamic. And one of the first things we did, because we have all these engineers, is let's build some little exercise equipment. And sure enough, we could build these little machines that could pull them. And they could stretch them, and you could then figure out, okay what's the best type of exercise for tendons and ligaments. And so, when we started doing this work we thought coming from the muscle field, that you have to do a lot of work. The early work that had come out of Copenhagen out of Michael Kjær's lab, most of the studies were on these 37 kilometer runs, and then they'd look at how much collagen synthesis there would be in the patellar tendon or the Achilles tendon. So we thought it was going to take a lot. And we started doing these experiments, and we'd dial everything back and in the end, it took less than 10 minutes in order to maximally activate the cells within these tendons or ligaments.

Geoff

Interesting.

Keith B.

And so, we were really ... we thought that was insane. And then we went to the literature, and sure enough if you look, bones are basically, they're ligaments that have been mineralized. So, it wasn't too surprising then, when we found the bone literature, it showed the same thing.

Geoff

Ten minutes to load-

Keith B.

Because as little as 40 loads to maximally activate or maximally increase bone collagen and bone mineralization. So you get this maximal effect with 40 loads. And then, if you were to do 40 loads then you ask how long you have to wait before you do it again. And it took between six and eight hours. And when we did it with our engineered ligaments, it was exactly the same. So you would maximally activate it in about 10 minutes. And then we'd wait, we wait we waited all kinds of different times, but it seemed like we'd get back maximal activation again after six hours.

Geoff

So 40 little like twitches at maximal load and you're done and wait six to eight hours, and that's optimal.

Keith B.

Yeah. So there's literature in humans in the bone field, where they would do 10 jumps three times a week. Jump as high as you can 10 times in a day, just at this period of time, and you'd do that three times a week and then they looked at bone accretion rate, and the bone accretion rate increased. So it takes a very small amount for these connective tissues. When we did the final study in the ligaments, where we'd pull them for 10 minutes and we'd let them rest for six hours, we'd pull them for 10 minutes. And we did that continuous, like that 10 minute intermittent stress, where we'd stretch them continuously for 24 hours a day, again because these are little machines that we can do this with, we found that you actually got more collagen synthesis and a stronger tissue when you did just the 40 minutes a day, rather than you did 24 hours a day. And so that was the first time that we started thinking about, okay there's exercises that can be specific for our connective tissues, and there's exercises that can be more important for our hearts and our skeletal muscle.

And then we started asking about nutrition, because the medias that we get are not unlike some sort of a soup that we feed these constructs, these ligaments. And what we found is that when we added more proline to the constructs, we actually see more collagen and they'd be stronger. And it makes sense, because a tendon is made of collagen and collagen is a repeating sequence of glycine and the amino acid and then proline. And so, if you have more proline, or if you have more glycine, you should be able to synthesize more collagen. And so, that was what we had discovered in our ligaments, is that's exactly what we found. There's some work out of Brazil that says, if you have tendinopathy and you feed rats really high amounts of glycine, something that's not really possible in a human that amount of glycine, but you can actually improve collagen synthesis and repair some of the tendons.

So what I did is, I did just did a simple, here's what you do, you could Google whatever foods are rich in proline, and up comes gelatin. So I was like, okay well, this, then and I tried to talk for I think it was three or four years, I tried to talk people into doing this, because we'd found this in our engineered ligaments, we didn't do human work at the time, and so somebody's gotta do the study where just feed people gelatin and see whether you increase collagen synthesis. And after three or four years, when we couldn't get anybody to do it, we finally did it Greg Shaw at the Australian Institute of Sport. And so we both ... you know, it's this really nice paper in The American Journal of Clinical Nutrition, but it's kinda limited in scope because not too many people in it and there were only a couple of treatments, but that's because it was Greg and I paying for it out of our own pockets. So we couldn't afford to do much.

But what we did is, we fed people either a placebo five or 15 grams of gelatin. And we measured how much the amino acids increased in your blood after after this. And we had done this, and we looked over time and all of the amino acids that are high in collagen, like glycine and proline, hydroxyproline, hydroxylysine, they go way up at about an hour after you drink the collagen or the gelatin. And then, so what we have them do is, an hour after we had them drink the gelatin, we had them jump rope for six minutes, because we had shown that these short bouts are enough. And sure enough when we do that, we saw this nice increase in collagen synthesis. And when we looked at the placebo or the five gram group, there wasn't a bigger increase with five grams, but when we did 15 grams of gelatin, we actually doubled collagen synthesis.

Geoff

And what is the biomarker for collagen synthesis?

Keith B.

We used this marker which is P1NP, which is the internal peptide of collagen one. So it's the pro-collagen one internal peptide. And so when you make collagen, you have to cut off the two ends, the C and the N terminal in order for it to go into the triple helix to make the actual collagen. So we used that as a marker. Because we're taking it from the blood, because there's so much bone in the body, it's really, when we take it from the blood the P1NP is mostly coming from bone. And so, what we had done, is we had seen that bone collagen synthesis could be increased with exercise and nutrition together, if you do the nutrition as a gelatin.

And the other thing that we did is, we took blood at an hour and we put it on to our engineered ligaments, and we grew it either from before they took the drink, or an hour after they took the drink. And what we saw is that an hour after the drink there was a dose dependent increase in collagen in the engineered ligaments. So there's something in your blood that we can isolate your blood, you know, just take the serum from that which has the amino acids, it has all these other things, and when we add that to our engineered ligaments it makes them stronger and gives them more collagen.

Geoff

And it's not even exercising these little ... something, okay.

Keith B.

It was just giving them the food. So if we can deliver it to them, it's a positive effect. So what we think we're doing is, the exercise was delivering it to where we were trying to get it, and then the nutrition was giving us a beneficial effect. And so, that was the first human study on that. And then the first kind of-

Geoff

And didn't you add some vitamin C to that? Because I think that's something that probably most people don't realize. I think most have seen gelatin or collagen supplements, but there's no vitamin C in that. And it sounds like you, you know.

Keith B.

So that becomes important, especially for our study design. We use people who are overnight fasted. And because our bodies don't produce vitamin C, we actually need it from a dietary source. If we don't have it, we get scurvy and that was actually the first nutrition study ever was in the 1700s, a study on scurvy. Because overnight you consume most of the vitamin C within your body, if you don't provide vitamin C when you take the gelatin or the collagen, what you do is you don't see the increase in protein in collagen synthesis. And we know that from two studies that we've done, and we mistakenly did this, because we were expecting this to have a positive effect and we didn't see anything. And the only thing we could figure out is that, we didn't have vitamin C.

And the first study was, we took gelatin and hydrolyzed collagen and compared them, and they're about the same on average. The gelatin in our groups was a little bit better, but not statistically significant. And then what we did is we combined ... so we did 15 grams of either gelatin and hydrolyzed collagen, or we combined 7.5 of each into a gummy, so we actually made it up. We boiled it, we made it up into a gelatin and people would eat the Jello. And what we realized in hindsight is that, when we boiled the juice, you killed the vitamin C. So the result is, that in the gummy there was no increase in collagen synthesis. So it was exactly the same as the placebo. So the hydrolyzed collagen and the gelatin were increased over the placebo and the gummy. And so we had first thought that, oh because it's hard, it's not being digested and absorbed. So we measured amino acid content in the blood, it's exactly the same. So it had to have been that there was no vitamin C. So if you're just getting up in the morning, and you're getting a coffee and you're just putting in collagen, which I've seen people say that this is the way to take collagen, you're not actually going to have the positive effect on collagen synthesis.

Geoff

Unless you drink orange juice with it.

Keith B.

Or you take it in some source. But a lot of the people that are doing that, are doing it as kind of an intermittent fasting, so this is an early morning thing where they're not going to take in anything else, and they're staying away from a juice like an orange juice, because they're worried about the carbohydrate load. So what they're doing is they're actually ending up with something that's not going to be useful.

Geoff

An expensive placebo.

Keith B.

An expensive placebo.

Geoff

That's a very practical tip for folks listening.

Keith B.

So the easiest thing is just, you can go to any place and get a powdered ascorbic acid, you just put a little tiny bit and you can make your gummy into a sour gummy, and you can then eat it that way, and it's perfectly good that way. But you do want to make sure that you actually keep your vitamin C in the fridge, because it is very sensitive to temperature changes. So if you have it you know, just sitting out and it's in a sunlit area, you can actually lose vitamin C activity in your supplement very quickly.

And again, you don't need much. So when we're talking about supplements, all of our studies have only used 50 milligrams so far. So that's right at the daily recommended allowance. So it's not like ... so that's an orange essentially. So some of the pro athletes that we do it with, what they do is they take an orange juice and they add the collagen or gelatin to that, and they make either a slurry if it's the gelatin, or it dissolves if it's the hydrolyzed collagen, they just drink that.

And especially if you're gonna take it as part of a bigger program where you're trying to decrease other macronutrients. If you're trying to decrease some sugars and you're not having juices, that's one of the big sources of vitamin C. So you have to be a little bit ... you have to think about it a little bit more if you're gonna be doing it in a very specific, a very regimented diet.

Geoff

I want to move on to exercise delta. I think people have probably read in the news about PPAR-delta as this very interesting targets, and there's been, in won't say fairly splashy magazine articles about how these people or delta agonists are going to completely replace exercise, and then they'd just gave a lot of people cancer, and it really failed. I know you've been looking and exploring this space. Curious to hear your thoughts on this category and what do you think is exciting in this space?

Keith B.

So people are, especially for muscle, PPAR-delta was seen as this really great thing. Because Ron Evans had developed these animals that overexpressed PPAR-delta and-

Geoff

Animals, right.

Keith B.

They could run forever, they'd just run forever. And so the idea then was that, okay, if we just activate PPAR, we can get the same response as exercise, we can get this endurance response. And it's actually one of the interesting things about a ketogenic diet, and this is one of the reasons why we're interested in some of the things we're interested in right now. Because collaborator, Professor Gino Cortopossi at UC Davis, when we were doing the ketogenic diet studies, he was doing whole genome analysis to see what kind of genetic changes were happening in the body. And the thing that came up is the number one upregulated pathway, was PPAR-delta or PPAR. PPAR activity goes way up. And the reason it goes up is because these transcription factors are fatty acid activated transcription factors. So we know that they're activated by fatty acids. If you have a ketogenic diet and you have a richer fatty acid pool, you're going to increase PPAR. It makes sense because the PPARs, one of the main things that they do, they upregulate pyruvate dehydrogenase kinase, which then phosphorylates PDH, that means that carbohydrate can't get into the TCA cycle, so that more fat can be used as a fuel.

It does all kinds of other things, increasing fatty acid oxidation enzymes, and all of these other really great things, but that's one of the key things that it does is it shifts metabolism towards fatty acid use. We got interested in it when I had my first laboratory in Scotland because, one of the things that I had heard about it, these little sandpipers, that had changed their migratory pattern so that they ended up in the Bay of Fundy every year, before they did this huge like 3,000, 5,000 mile flight. And the interesting thing about the Bay of Fundy, is that they had these little crustaceans that were the richest source of omega 3 fatty acids that could potentially activate PPARs. And so, they had changed ... evolutionarily they had figured out that these things would increase their fatty acid oxidation capacity and increase their exercise capacity, so if they flew there and they took in this nutrient dense source of omega 3 fatty acids, that they then had this huge mitochondrial effect without exercising extensively because-

Geoff

And it's better for fitness and they survived.

Keith B.

Exactly. So they had changed their whole migratory pattern. And so we had come up with this idea that if we could figure out a way that we could use natural products to activate PPAR, and be well below some of the drugs that people use that cause the brain cancer issues that were problematic, that we could actually do something that would increase the ability to use fat as a fuel, increase the effects of exercise, or potentially mimic exercises ability to shift that. And so we had started doing that. I had a postdoc Kurt Watson, who was really good, I immediately wanted to hire him because he was Dr. Watson and I thought that was the greatest thing, being a huge Sherlock Holmes fan, that's the greatest name-

Geoff

Dr. Watson.

Keith B.

Yeah, exactly. That would be wonderful. And he came up with this really cool system, where we could use muscle cells, and we could actually go in and he could put a few things in the muscle cells, and then he'd give us a readout, as to whether we've activated PPAR-delta. And it was specific to PPAR-delta, because we would try the other PPARs and it would give us no activity. So it was this really cool assay. Then we went in and we screened hundreds and hundreds of natural products, and then we found a bunch of them that activated this in muscle. And then what we did is, used the same engineering techniques that we've used in the past where, what we do, in a single experiment we add a little bit of each one into all of the different, but in different amounts. So what you do is in one experiment you say, "What's the optimal concentration in combination of all of these different potential activators?"

And so, we had come up with three of these things that when you did all of these engineering experiments, that was the optimal combination and concentration. And so, there's just a couple of things that are GRAS certified, they're impossible to pronounce, so I won't even bother, but one of them is gamma-linolenic acid which is a normal PPAR-delta agonist. And so the other two work together with it, and we got something on the order of a five to six fold increase in PPAR activity, where the drugs were giving us 16 to 20 fold. So it was right in this really nice sweet spot. So now what we're doing is, we're going in to see whether we can use that as a way to mimic the exercise. For a lot of the people who are listening and watching this, they're doing something similar if they're doing a ketogenic diet. Because one of the things that we think is really positive about the ketogenic diet is that it's activating the PPARs. And we think that that is really positive, just like we had talked earlier about mTOR being something that we want to keep down at certain times, and then activate and have that dynamic range, we think one of the things that's important for maintaining longevity is this possibility of shifting towards fatty acid metabolism.

Is there ability to shift toward fatty acid and maintain mitochondrial function. Some of the work that we haven't published from our long ketogenic diet study, we've looked at the muscle, and in the old animals on a ketogenic diet, they have more muscle, they've maintained their muscle. It's not that they've grown their muscle, it's just that they haven't lost it as much as the control animals. And they have better endurance, their endurance is the same as when they were young, even though they haven't exercised. And so there's different things in there that seem to really have an exercise mimetic affect. They're not gonna do everything that the exercise does, but they're going to have some of the components. And then to do those types of things together with a little bit of exercise, probably -

Geoff

Synergize.

Keith B.

We think it'll synergize.

Geoff

You think this it'll synergize on top of a keto diet, exercise and PPAR agonist, hopefully you triple up the benefits?

Keith B.

I don't know whether it's gonna be an additive effect like that, it could be that the exercise and the keto is potentially something that's enough to get the PPAR-delta activity.

Geoff

So you're saying maxing it out or something?

Keith B.

Potentially, but we don't know. One of the things that we had seen, is one of the one of the ways that is really big in training is this low glycogen training. And specifically you train twice in a day or you train in the evening and you sleep in a low glycogen situation, and you get up in the morning. And you do a second exercise bout in a glycogen depleted state. And one of the things that we had seen early on with that, when we had been doing some work with Oscar and John Hawley, is that when we did this in a rat model, the one thing that we saw was that, when you did exercise into glycogen depleted state, the biggest effect that we saw was this huge increase in PPAR-delta activity.

Geoff

Makes sense, yep.

Keith B.

So we saw this really big increase in PPAR-delta binding to its transcriptional targets-

Geoff

Because the only thing you have is fat, so you've really got to be fat oxylating really, really efficiently, so it makes sense.

Keith B.

Exactly. And there's a huge metabolic demand, and the only thing you've got is fatty acids. So now that together is giving you this big signal, the exercise alone didn't give you. So we think that some of it is to do that. Now, the low glycogen training is designed to specifically overcome one aspect of the whole fat adaptation, and that's this idea that when you fat adapt completely, what you're doing is you're actually decreasing the ability to use carbohydrate. And so, what you do by this intermittent low glycogen training, you get the PPAR-delta activation, but you don't get it to the extent that it overrides the ability to use carbohydrate. Because as we talked about earlier, PPAR-delta increases PDK1, which blocks PDH, and trends downwards and beautifully shown that when you try and do a sprint, and actually Tim Noakes was the first one to show, is that your ability to do distance when you're fat adapted was maintained and you could go hard, but you couldn't do the sprints.

And so he had done this long distance cycling race, and it had, I think it was eight sprints in it. And so Tim Noakes had shown that, the fat adapted group did fine on the distance, but they didn't do as well on the sprint. And Trent Stellingwerf had shown during his PhD, that when you do the fat adaptation and you try and sprint on the bike, you can't sprint as much. And when they took biopsies what they say was that PDH activity had gone down. So you couldn't get glucose in.

Geoff

It's a trade off.

Keith B.

Exactly. But that's why doing it intermittently through the low glycogen training, you still can use carbohydrate, but now you've had the ability to have a transient increase in PPAR activity. And so that's why when you do the sleep low studies, John Hawley's done these studies, you can see this increase in performance based on you're still able to use carbohydrate, you're still able to sprint, but you had a better adaptation-

Geoff

For fat oxidation.

Keith B.

For fat-

Geoff

I think that's another subtle point that I don't think most people talk about. I think we talked a lot about the benefits of a ketogenic diet, but you're also making a trade off for performance. And I think that's something that we've been focused more about. There's the orthogonal dimension between longevity and then performance. Sometimes they overlap, but many times I think in this particular case, they're not necessarily overlapping, or they're just opposite goals.

Keith B.

Right, and I right the best example for me was a few years ago, LeBron James, and this one I use with my students, LeBron James, everybody's like, "Oh my god, he's lost his step, he's looking, he's ripped but he's slow, and we don't know what's going on." And that summer he had gone on a high-fat low-carbohydrate diet, and he had lost weight and he looked great. And the nice thing about at the NBA, is you've got analytics there. And you can actually see that his velocity went down. He wasn't running as fast, and the distance he could cover fast went way down. He had this two week period where he took a break from basketball, he re-did his diet, he came back and everybody's like, "I don't know what he did in those two weeks, but he's moving so much better."

Geoff

He ate some carbs.

Keith B.

He just ate some carbs. And so he was back, and so now he's got a little bit of the adaptations, so he's lost some weight, now he can use carbohydrate again because he's gone off the complete low carbohydrate situation, and so now he's got a really good combination of the two worlds. Where he's at a better weight to be able to perform, now he can use carbohydrates so he can sprint better, and so his performance went way up. And everybody's like, "Oh my god, I don't know what ..." That's the classic example of what kind of things can happen. You don't necessarily get the big shoot back up in performance, unless you've had something like the body weight loss. So if you've lost a lot of fat mass when you've been doing it, and then you can get back, and give yourself enough time to get back so you can use carbohydrates as a fuel, now you've really got this benefit of having lost the weight, you can still use the fuel and you've had this adaptation where your mitochondria work better.

Geoff

I think some of the more keto advocates would say, well if you do six months of adaptation or 12 months of adaptation, you can get back up to peek performance. I haven't seen data on that, I mean, do you do you think that's a little bit of a stretch on pushing keto too aggressively?

Keith B.

I think it's a stretch, I do. I know, like the supernova studies that Louise Burke has been doing. They've been beautiful studies, they haven't gone six months or a year. It seems like no matter how long the studies go, that people who are like really passionate about it say, "Oh, you didn't go long enough." Well, you're in ketosis for a long period of time. We can produce ketosis in a matter of minutes just by doing the right nutritional things. You can produce ketosis with your product without having any change in diet. And so you can do those things, you can see a lot of the positive effects. And so, we can actually do, and some of the studies we've been doing in mice now, we have moved to these intermittent ketogenic diets. So it's one or two days, on a ketogenic diet, and then a few days, and then a week off. So when we had published or cell metabolism paper, there was another paper from people at UCSF who had done the intermittent ketogenic diet, and they saw the same effect on longevity. So it's not that you have to fat adapt, it's not that you have to become fully adapted to the keto diet in order to have the beneficial effects on longevity and these other things. So I'm not understanding really, how that's going to be important for getting back the performance, and I don't see it coming back.

Geoff

I mean, it seems like you plateau out your fat oxidation ability pretty quickly, and at a certain point you just need glucose for anaerobic activity.

Keith B.

Well you just need glucose to go fast. Because what limits how fast we go, is how quickly we can produce energy. And so it takes more time to produce energy using fatty acids. It is a thermogenic reality. So it takes more time, so you have to go down a little bit slower so that you have enough time to produce the energy. And so, if you're completely fat adapted and you're blocking glucose entry into TCA cycle, you have to go a little bit slower in order to allow it.

Geoff

Do you think the paradigm might shift with things like Ketone Ester, or some of your PPAR-delta agonists? I think I would still agree with you that, for optimal performance, even if you have a ketone ester, you probably want to up, you want to preload with carbohydrates as well to maximize all possible fuels. And I think that's we recommend. It's like hey, get as much as every single possible substrate in there.

Keith B.

So the nice things about some of the keto esters, is that they can get into the muscle really easily, and they can get into the mitochondria really easily. So as soon as you put in a keto ester, or ketone, what you see is you see this huge increase in acetyl-CoA. And so, it's getting into the mitochondria really quickly. So what you're doing is you're providing more sources of acetyl-CoA. And that has the potential to then, if acetyl-CoA is then driving TCA and how quickly you can produce energy, if you can do two things at once and you can get acetyl-CoA from two different sources, that's entirely different than -

Geoff

Fat oxidation, yep.

Keith B.

Or if you've just got a carbohydrate, because then you've acetyl-CoA only from one. And so, if that's driving the rate at which you can produce energy and the limit is how much you can get in at that level, then potentially you're gonna have a beneficial effect, and that's what the cell paper really showed, was that with the keto ester, you saw this increase in performance. It wasn't that you were blocking carbohydrate performance, or oxidation, you just were adding a little bit of another type of energy that could then produce energy faster and you go faster.

And so that's really attractive about this. Because scientifically, the biggest thing that we see, if we add in a ketone, the number one thing that we see almost immediately is an increase in acetylated proteins. And that's just because there's more acetyl-CoA. And so, we think that it's really quickly broken down to that acetyl-CoA, so you can either acetylate proteins, or you can have these other effects like driving metabolism. That we think it's important as well, because you're acetylating proteins and that can stabilize some. One of the proteins you acetylate, is dysregulated by acetylation, is PGC-1alpha, which is important in mitochondrial biogenesis, so we think that that's one of the reasons that you get more mitochondria on the ketogenic diet, is because you've got this increase in PGS-1alpha activity.

We also think there's other targets that are acetylated and that regulates, say growth. So one of the reasons that we're anticancer it our animal study when we had this ketogenic diet, with some of the proteins that regulate growth in a general form, they become acetylated, they become stabilized, and they accumulate to a greater degree. So we think that the ability to get in and be converted into acetyl-CoA quickly, it's one of the great positive effects the ketone. So if you can do that without sacrificing glucose entry into the cycle, now you've got the...

Geoff

The best of both worlds.

Keith B.

Potentially yeah.

Geoff

And one thing that I think it's interesting, I don't think it's necessarily resolved, is that people will talk about the benefits of ketones or ketosis in general, I think it's kind of conflated. How much of the benefit do you think is from going on a ketogenic diet with a dietary restriction of carbohydrate, how much do you think is because of the signaling affect of beta-hydroxybutyrate or a ketone body itself? My stance on this, like it's a bit of both. There's some Venn diagram of overlap and some that are distinct. Curious to hear you unpack some of the nuances there. Because I know that HDAC inhibition is probably based on beta-hydroxybutyrate itself, which is interesting for potential longevity.

Keith B.

Potentially. But it's also modulated by acetylation.

Geoff

Right. So that's for like hitting the nuance, and I think there's more work to be done.

Keith B.

So the best thing that we have so far, is our cell metabolism study, where we did the low carbohydrate high fat, but we kept protein high, so ketone levels were low, versus the one where we drop the protein a little bit and we got the higher ketone levels. Yes, we decreased protein and protein is associated with longevity as well, but we decreased protein to only 10%. So that's still above their recommended daily allowance for a mouse. So, they still had enough protein to do everything, so they weren't in a protein deficient sense. What you see there, is the low carbohydrate high fat diet, you have a 6% increase in longevity, the ketones seem to be driving an extra doubling of it. If we look at things like acetylation, the low carbohydrate diet animals, had no change in acetylation. It was only the ketogenic diet that saw the big shift in acetylation. So some things are distinct from the low carbohydrate. Because low carbohydrate was zero carbohydrates, so it was no carbohydrate in both, but in one you had protein and in the other you didn't, so that you can drive ketogenesis. Because in the mice, you need to have lower proteins to drive ketogenesis.

So we think that there are very specific things that are driven by the ketone, and there's different things that are modulated by the carbohydrate level. And so, for us it's really about trying to understand is that just because the ketone. And so, one of the things that we've been looking at is actually looking at Karen Clark and potentially working with her to say, okay if we just give a keto ester, do we see all of the same benefits. And in some of the initial stuff we seem to think that we can if it's the right. Because the keto salts are problematic, there are all kinds of different delivery possibilities, but at least for the ones that we've seen, it seems like there's something specific about the ketone. And we don't know whether it's binding to a receptor and activating an G coupled receptor, which is something that's been proposed. Or whether it's just coming in driving acetylation, driving this change in acetyl-CoA, which then increases acetylation rates, and if you've got enzymes like histone deacetylase, if you've shifted everything towards acetylation, is that enzyme than functionally inhibited, because you're just driving acetylation. And that's one of the things that we've proposed.

Geoff

I see.

Keith B.

Is that yes, we're getting acetylation of proteins like PC1-alpha, which has got this good effect. We're also driving the acetylation ratio towards pro-acetylation. So if you're at deacetylase, and now that's histone deacetylase inhibition, we've shown that increases mitochondrial mass. That was stuff that we had done with Sean McGee in Australia, he had done a postdoc with me in Scotland and we had started that. And then he had gone to his own lab and continued. But when you use something that blocks histone deacetylase, you get an increase in mitochondrial mass, you get an increase in fat and carbohydrate utilization. So you get all of these interesting ... so is the ketone giving you acetyl-CoA, driving acetylation towards that side, away from the deacetylase, and it's functionally inhibited the deacetylase.

You know, because that's the way some of these things work. So the [Corey's 01:12:02] had discovered, they were gonna measure phosphorylation. And what they did is, they took this glycerol phosphate, and they added it into their buffers when they were homogenizing up tissue. And when they did that, now they can see phosphorylation. But without those buffers they couldn't see it. And all it did was give a ton of phosphate. So if there's lots of phosphate the enzymes that take the phosphate off are inhibited, because you're so much phosphate that they buy into that instead of buying into their target. So is that what's happening with the ketone? It's coming into the mitochondria, you get all these acetylations, and now you've driven everything away, or you've produced so much acetyl-CoA, that you're now functionally inhibiting HDACs.

Geoff

Right. See, I think that's where it's exciting to see that science is still at the cutting edge.

Keith B.

Exactly.

Geoff

And hopefully we can ... the big group of folks, whether at Oxford or Karen Clark, we can help make it happen. I think that would be very fascinating to understand, what is the dominating factor. I presume a little bit of both, but it would be interesting to understand what is the dominating factor. Whether it's the ketone itself, or the process of ketogenesis.

Keith B.

Exactly. But we know that there's enough from some of the keto ester stuff, that says there's functional things happening when you're fully on a regular diet, when you take a keto ester. So that's telling us the ketone is doing something.

Geoff

100%. What's on your deck for 2019? I mean, I think the broad areas that we cover, I think are super fascinating to us, specifically our audience, but on the horizon, obviously, potential work with ketones, keto esters and all of that, but on your docket, what do you think is the most exciting in 2019, 2020?

Keith B.

It's an interesting day for me today, because I'm sitting nervously because our grant at NIH is right now being decided whether it's gonna get funded. So we'll find out to day whether our ketogenesis diet and longevity studies are going to be funded as of today. So we're hoping that that goes through. And then, we've got this project that we're gonna move through on really trying to understand how the ketogenic diet affects the neuronal component. And what we're thinking is it's coming from muscle. So there's a signal that's coming from muscle that's maintaining the brain function. And we know that individuals who are active and have more muscular activity have better brain function. So what we're trying to do is, we're trying to see whether the ketogenic diet is having these direct effects on the muscle, and whether if we block what happens at the muscle, do we stop the positive effects of the ketogenic diet in the brain.

Geoff

That's interesting.

Keith B.

Can we get in and mimic it.

Geoff

I would say that, I think some of our conversations with folks that have been looking at the connection with ketogenic diet with conditions like Alzheimer's, would go for more of the direct link, where you might have insulin resistance, or glucose uptake dysfunction in your neurons, can ketone bodies be this alternate fuel source that rescues brain function. But you're suggesting that maybe that's a component, but also this component from the muscle, which I hadn't heard before.

Keith B.

We think that there is a component that's coming from muscle.

Geoff

Interesting.

Keith B.

And again, the muscle functionality and this ability to shift it towards fatty acid utilization is changing metabolism within the muscle, and that's giving us an increase in the ability to have the brain function properly. We've got really interesting preliminary data that would suggest that that's a possibility. And so, that's a cool thing that we're looking at. We're doing a lot of things with injury and recovery right now, because one of the things that happens is we're trying to, for years we've been promoting, you know, activity is great, and then you get to a point where you can't do activity anymore, because people tell me that their body's breaking down, and how their body's breaking down. And so, what can we do to maximize recovery from tendinopathy.

So I have a student now who's got a model of tendinopathy, where we put a little hole into the patellar tendon. And then what she's gonna do is, she's going to use some of these same engineering techniques to try and figure out what's the optimal exercise program for returning that tendon to fully functioning proper tendon. Because even though muscle strains, sprains and injuries are the number one thing that causes time away from work and it cost billions of dollars every year, we only have this idea that, "Oh, you should stay off it for a while." [crosstalk 01:16:29].

There's not really anything. There's this idea that if you do these slow lengthening contractions and you do them all the time that it's really difficult to do. And we had a case study published with one of the professional basketball teams we work with where, we had an individual who had a central core patellar tendinopathy. And you could see it on the MRI, there's a hole in his patellar tendon. We put him on a specific exercise plan with a little bit of nutrition. And then 12 months later the hole is gone, 18 months later we gave the MRI to an independent orthopedic surgeon who was telling us about things that were going on in the knee in other places, but the patellar tendon was completely normal. And so, that's really strange, because everybody had always said you got to treat the donut so the healthy part of the tendon, not the hole, because they didn't think you could actually fix the hole.

Geoff

Interesting.

Keith B.

So because we were able to do that in the human, now we want to know whether we can reproduce that completely in the animal, and then understand what the genetic profile is, so that we can then say ... And this is one of the cool things you can do is, I can go in and give the best optimal exercise program to that patellar tendon, take out the area of interest, and identify the genes that are activated. And then I can go to this connectivity map, where it's got 1,300 natural products, and I can see whether the genetic signature that I have from my exercise matches with any of these natural products that people have already characterized, and now you already have things, that oh, well that should help as well. So now, can we target that. So we'll use the exercise together with that, because they're both having the same genetic signature. So things like that are going to be things that I think are really cool. We've got all kinds of other things happening with the idea of inflammatory tendonitis.

Geoff

That seems like a really cool infrastructure and pipeline right? So you have this connectivity map, you have targets, you're just going together.

Keith B.

Exactly.

Geoff

Potential solutions with problems.

Keith B.

Exactly. And so it's really cool, because what we can do is, we can manipulate things on a genetic level. We've then got these 3D engineered models where we can mechanically test to see how strong we've gotten something. We can then go into an animal model, and then we can go up to the human. And so, we've got this one right now that we're working on, because women rupture their ACLs four times more than men. And we had shown that using our engineered ligaments, if we treat them with estrogen, their stiffness goes down, and the collagen's maintained.

And so, that's really cool, because that means that what you're doing is you're affecting this protein that crosslinks the collagen, and so it's not as strong. So we then looked at natural products that could cross link protein and sure enough, we found a sulfur based molecule, just MSM, you know, a lot of the joint health medications, is usually chondroitin, glucosamine and MSM. If you just take the MSM, what it does is it cross links protein. When you put it in together with estrogen we actually make the ligaments stronger. So whereas, before you would get a weaker ligament, we actually made the ligament stronger when they had the MSM together with the estrogen. So we've done that in the culture model, and now we're actually going to do a human study. We're starting the human study to see whether if we measure knee laxity in women when they have their luteal surge and estrogen's high, their knee can be one to three millimeters more lax. So we're going to test that for a couple of months. Then we're going to do a randomized double blinded study, where they get MSM or a placebo, and see whether taking MSM for three months can now decrease the laxity that happens when estrogen rises.

Geoff

I thought that was really interesting when you presenting that data, because that also might inform how coaches might use their players, depending on where the woman is in her cycle, right.

Keith B.

Exactly.

Geoff

That's definitely important to understand in terms of training blocks.

Keith B.

It's mandatory, because estrogen is really essential for muscle repair. So if you have higher estrogen your muscle repairs better. But it's also got the possibility of causing catastrophic injury to the tendon and ligament. So we just had a paper with one of my new students, she's an outstanding PhD student originally from Nigeria. She's 19 years old and a second year PhD student-

Geoff

Whoa-

Keith B.

So she's well smarter than me. But what she's done is, she's written a nice review of how you would put training together with estrogen. So if you're an active woman, how would you want your estrogen levels to be. And then what we suggest is, look, if you're training for performance at a certain time of year where you're a track athlete and you're going to go to the USAs, or you're going to go to some competitive environment, what you would do is, you would naturally be cycling during the year, and then what you would do is you would go on to a low progesterone oral contraceptive, so that your estrogen is maintained when you get close to competition. You don't want to do it for too long, because then your muscle is gonna not recover as well, but you would do that for maybe a couple of months to two months before competition, so that your performance level will be high, and then you would cycle back out of that.

So it really talks about what we're seeing for a lot of these things. That a ketogenic diet might be great for certain period of time. Other things might be great at other times. But really, just saying I'm gonna do this. If I have a family history of cancer, a ketogenic diet is gonna be something ... or if I find out that I have a cancer, I'm on that, and I'm going to be taking that for sure. And it's going to be as long as I can. If I've got other issues, I'm going to do ... but what you want to do when you're not in that situation, you want to vary things.

We talk about, people have done this with altitude, people have done this with other things, with glucose. So low glycogen training during the base phase, and then as you get closer, you're gonna be replete with glycogen so your performance is best. Same thing seems to be true with estrogen. That you want to have it cycling normally when you're training, but then as soon as you get into a competitive phase, now you don't want that cycle anymore, because catastrophic risk is too high. Your performance is actually go down as well. Because the same thing that makes your knee lax at the ACL, makes your tendon less stiff and that decreases your performance. So, it's one of the reasons why women produce less power than men, is that they can't transmit the force as quickly because they have less stiffness in their connective tissue.

So knowing these things and trying to put it all into a single system, you can come up with those types of things, but you really can't just say, oh you're a runner, you should do this.

Geoff

No one size fits all thing. You need to time it. Yeah, I think these ideas are finally transmitting or have been transmitting in the last few years, where I think you time your nutrition, all the sort of cycles that you have. Last couple questions here. One, obviously you've been looking at a lot of these lifestyle nutritional interventions, which ones have you adopted personally if you do that sort of thing. What has passed your personal bar of confidence. And then two, it seems like there's more and more serious inquiry, at least I would say from the consumer side, around antiaging and longevity, we were hinting about what the ketogenic studies. Do you think that is also happening within the academic community? Or is it just sort of same old glacial progress, year by year. Or is it sort of an inflection point where like there's actually much more funding opportunities for that space?

Keith B.

So, we'll start with the second one first. So are far as when we look at these types of interventions and we think about what the future is, and how and whether there's interest in the academic sense. There's definitely interest. Filipe, who runs the division of aging biology at NIH, he says that most diseases that you see are actually aging diseases. Because what we've done, is we've treated heart disease well, so now people live longer, because it used to kill one in two very young, a lot of them very young. So now what we're seeing is a lot of these diseases we're seeing, are diseases that are really ageism. It's a product of age. So there's a huge interest academically to understand what's going on, and how aging is associated with all these other factors, to then say, this is the outcome that you get. This is how long you're going to live because you have this genetics, you have this diet, you have this habitual activity, and this is where you end up. Because we always see these people who say, oh yeah, you know, the interviews with the guy who turns 100, oh yeah, my secret is a cigar every day, and drinking alcohol-

Geoff

Drinking whiskey.

Keith B.

And doing all these things, and you're just like, how did that happen? Well it's you know, if you interviewed everybody that would be the outlier, but that's the one that we hear about. So, there's this huge interest academically. And there is more funding coming into it. Especially right now, over a lot of the neural neurocognitive diseases, because again Alzheimer's is really an aging issue, it's not that Alzheimer's didn't used to exist-

Geoff

No one survived long enough to get it.

Keith B.

Nobody lived long enough to get it. So you weren't worried about what would happen to you in your seventies, because you were hoping to make 50. Now that we're looking at, okay 70, 80 is our mean lifespan, now you're thinking okay, all of these other things have to be taken care of. And that's why a lot more effort is being put into neurocognitive disease, because those are just showing up now, and we still don't know much about them. As far as what things I have adopted myself. So I got into it because I loved activity. So I've always done activity.

Geoff

That's because a lot of academics, they're proud that they're not athletes and they're like physiologists, kind of like okay, I get it, you want to be distinct from you study population, but I respect that you know, you're in there.

Keith B.

I just really feel like look, the majority of the work that I do looks at muscle mass and strength, and how it affects longevity and performance. And I'm like why would I not lift weights? And that's the key thing for me, is to lift weights. I also run as much as I can, at least three times a week, I'm out running. But I'm trying to lift twice a week.

Geoff

How long are you running? Just curious?

Keith B.

I put in 20 to 25 miles a week.

Geoff

Nice.

Keith B.

So it's a little bit, but the key thing for me is I'll go in and lift weights, and that's the harder one for a lot of people. And they think it's hard because they think, "Oh, you gotta go into the gym and it's gonna take hours." But the work is clear, that if you want to be strong ... my workout takes 10 minutes.

Geoff

What is your workout?

Keith B.

So I'll start with legs...

Geoff

So is there spotting?

Keith B.

No, I go on the machines. And the reason I go on machines is because the literature is very clear, that if I lift weights to failure, my muscles will become bigger, and if I lift a heavy weight I will become stronger. So if I'm in a machine, what it does is it supports my small musculature, so that I'm not going to have any likelihood of injury. So I work with a lot of really elite athletes, I work with a lot of people who have to do modified squats, because they've ruined their back. Because as they try and go up in weight, the small muscles aren't strong enough, and that's where you fail. So I can get to failure on a heavy weight without assistance by doing it on a machine. So I'll go a leg extension, curls, leg press, and that'll be it. And it's just one set to failure. Come in, hit it, and just do the heaviest weight I can on that day for eight to twelve repetitions. When I hit 12, I go up in weight. And so, all that that does is, I'm not going to grow huge, but what it does is, it means that I'm going to grow stronger. Because it's clear now, that if you want to grow bigger, you need more volume. If you want to grow stronger, one set to failure is all you need. And so I'll go extension to curl, to press. And then I'll go a pressing exercise, a pulling exercise, and then to a shoulder exercise, and then I'll go back and do one more pull and one more press.

Geoff

So seven, eight-

Keith B.

Seven or eight exercises.

Geoff

To failure, done.

Keith B.

To failure, you're in and out.

Geoff

Ten minutes, pretty aggressive, 15 minutes I'll give it to you.

Keith B.

Ten to 15 minutes, yeah. And that's similar to what we did at Michigan. And these football players were huge, they were big strong guys. They didn't need to train for hours. Because if you go at a high intensity ... you know, we hear about high intensity exercise, everybody thinks it's intermittent endurance exercise. The first high intensity exercise that we used to talk about was, in the late eighties, high intensity exercise was this way of strength training going once set to failure, work as hard as you can for one set, and then as soon as you're done, that's all you do for that, and then you go on to the next step. And so that was high intensity training in the eighties.

Geoff

Truly going to failure, like the HIT training, kind of like kind of hard, but you're not going to failure.

Keith B.

Well, so the endurance based stuff is you're going as hard as you can, any intensity is not even gonna be close to your one rep maximum. So if you're cycling, yeah you're pushing really hard on a lot of resistance, but it's not close to one rep maximum on a leg press. So that's why the strength adaptation isn't as great when you do a high intensity, like an endurance based. So that's really where I've, a lot of ... and I go to failure because the other thing that happens at failure is, you move really slowly. And when you move really slowly that's the optimum thing for your tendons, because tendons respond to speed. And so if I move really quickly, my tendon becomes stiffer, and that's good for performance.

Keith B.

But if I want to have better health on my tendon, what I want to do is, I want to move it slowly. So as you go to failure, your movement starts going slower and slower. And the last one you're barely moving it, and that's actually optimal for tendons, because now you've got these shear forces that are breaking down some of the cross links and decreasing the stiffness there. And so that's really the biggest thing that I do, that's a core of what I've looked at scientifically.

Geoff

How about nutrition?

Keith B.

Nutrition wise, what I tend to do, is I try and not spread my calories over too ... so it's time restricted feeding to some degree.

Geoff

So it's a little bit like an intermittent fast like a 16/8.

Keith B.

It's like a 16/8 type of thing. And the only reason, I'm doing that because it's that easy to do. I'm not super strict, so in the morning I'll have a latte-

Geoff

Get some of the milk.

Keith B.

The milk is basically all I eat in the morning. So the reason for that is, yeah, we're doing the ketogenic diet in these animal studies, but in order to do it, we can't do it as ad lib diet, so we have to go in and every day we have to feed them. And this is what John Ramsey does better than anybody else in the world. He goes in and he weighs out and he feeds them. And what happens is, because they don't have food for a while, they immediately go and they eat what they have. And so, yes we're doing a ketogenic diet, but we're also doing time restricted feeding, because they're only eating once or twice a day. And so, what we've got is we've got this situation where they're going the rest of the day without feeding. And so I can't tell you scientifically whether it's actually the ketogenic diet, or whether it's the time restricted feeding.

Geoff

It's the one meal a day type of thing.

Keith B.

And a bunch of people are really getting into the time restricted feeding, as far as the scientific validity of it because there's all these circadian clocks that are really important for everything in the body, and some of them are dictated by the muscle, some of them are dictated by other systems in the body. And so, it could very well that the ketogenic diet is beneficial, but it could actually be some of this time restricted feeding component that's giving us some of the other effects.

Geoff

Right, so you're not overly restrictive on carbohydrates? you're just kind of-

Keith B.

I don't I don't pay attention to that. I have an 11 year old daughter, it wouldn't necessarily be something that ... I just want to you ... the biggest thing that we do is we make most all of the food that we eat. So we'll make it from scratch. And so that's for us the biggest thing. So we'll get real vegetables and cut them up and put in all the effort. I takes a lot more time, but I think that that's the biggest thing, because we don't have a lot of the processed food aspect of it. And there's some really nice data coming out now that no matter what you eat, if its processed more, it's actually got a detrimental effect. And so, those of the types of things that I use, but I'm not restrictive on anything. I don't focus on any specific macronutrient. Mind you, if we get some of these grants funded that tell us that on a caloric restricted diet when we manipulate macronutrients, that there's a clear winner there, it would be hard to not go for that.

Geoff

Yeah, let's be practical science driven. No, thanks so much for those conversations. Super, super interesting. I think it was a well nuanced conversation. Where do our folks follow your work? Are you on Twitter or on any social? Where do people keep in touch?

Keith B.

So I am on Twitter, I got on very early on, so I got a really good handle. I'm just at musclescience. So just musclescience is where my Twitter feed it. If people are interested in our work. The one thing that's really problematic for academic work, is a lot of times you go to look at a paper, because that's where it is, and it's behind a paywall. And what a lot of people don't understand is that, we're allowed to give out those papers. So if you email in to a professor who's written a paper that you're interested in, they will email that back to you. And it's one of the great things for most professors, because we sit there and we do all this work and then we publish something, and it sits there, and you don't have any idea whether anybody cares about it.

Keith B.

I used to have a chair of a department that would tell me, that he also wrote for Field and Stream because he was a big fisherman, so he would tell me that more people would read one of his articles in Field & Stream, than would read all of his scientific work combined. And so if you want an article that's not accessible, my email is-

Geoff

You might get a lot of email requests though.

Keith B.

Yeah, that's totally fine. That goes for most professors, is that if you see something, the way to do it is, you look at the last author, usually there's a-

Geoff

Corresponding author or senior author.

Keith B.

It's the corresponding author, and the email is usually given there. If you just email and email, whether it's me or whether it's somebody else, you'll get it usually within a few days. So that's the easiest way to stay up on kind of the really high end literature. So yeah, social media musclescience, keep up.

Geoff

Awesome Keith, thanks so much.