Geoff

Zach, really great to have you on the H.V.M.N. podcast and before we get started, I need to congratulate you on setting two world records recently. So you have the fastest 100 miler and you also, I think on that same attempt, basically did the longest distance ever covered in 12 hours. Correct me if I'm wrong, but I believe those are the two accomplishments. Again, very, very insane. This level of performance endurance there.

Zach B.

Yeah, well thanks so much for having me on, and thanks for the kind words too. But yeah, the world record was at and where I have it now, it's kind of in a unique spot where you can kind of double dip and go for the hundred mile and then if you have any bit of legs left, it behooves you to stay out there and see what you can do for 12 hours. So it's an interesting kind of set up.

Geoff

Yeah. And then to give our listeners a sense of the speed and that distance you were recovering, you're averaging, I believe like right around six minutes a mile, maybe even less than that over that a hundred mile run.

Zach B.

Yeah, it came out to, I think, just under 6:48 per mile was the average pace for the hundred miles side of it.

Geoff

And I think most people might be able to run half a mile at a 7:00 pace, maybe a mile if you're relatively fit. And then doing that for a hundred times in a row, over 12 hours is quite an accomplishment.

Zach B.

Yeah, it is kind of interesting. I think people don't always, at least the general running community, the ultra running community can kind of run the numbers. They kind of have an idea of what a hundred miles is and stuff. Most people who are running your traditional distances, they don't always think, well, what is an 11:19 for a hundred miles? But when you break it down as kind of the pace per mile, or it was 20 minutes, some high seconds, 5Ks, 32 of them in a row, or four marathons at 2:58 that's when they can kind of start to connect the dots a little bit in terms of kind of what the effort was I guess.

Geoff

Yep. I'm especially excited to talk with you because I think you cover and can speak highly towards a couple of key topics that we talk about on the program here. One is low carb, high fat nutrition, and what that means in terms of metabolic health but also in terms of performance. And I would say the other big topic that we like to cover is a high end human performance. How do we enhance ourselves, and I think from a confident perspective, being the best in the world at something definitely surpasses that mark there. Perhaps the way to get started here is, how does one decide to be the fastest a hundred miler in the world?

Zach B.

It's funny, because I think you end up in that position at some point. You don't necessarily plan for it. But for me, I got into running as early as in middle school. It was my first kind of exposure to endurance events in general. And that was more or less just because I realized fairly quickly that I could be kind of near the front if I ran distance, or I can be near the back if I ran sprints. So as a middle school aged boy you kind of gravitate towards what your interests are, which tend to be what you're better at. So I had a little bit of maybe a nudge in that direction from those experiences.

And then, in high school and college I started getting more and more interested in the sport as a whole. And by the end of my college experience I started getting really interested in just kind of the training methodology and the hows and the whys. Rather than just going for a run or doing a workout because the coach said do this workout, trying to figure out well why would we do that workout then why do we put this here and where does recovery fit into the equation? And all that sort of stuff.

So one of the biggest takes I had during my college running experience was that my favorite workout of the week was the long run. So after college, when I kind of was removed from some of that structure of the team atmosphere, and the coach and all that stuff, I started kind of just gravitating to doing more of the stuff I liked versus what I felt like I had to do to meet peak potential in a specific event.

Geoff

So when was your event in college?

Zach B.

I did mostly like 5K and 10K for track, and then 8K for cross country.

Geoff

So relatively short. So you are not a marathoner in college?

Zach B.

No, you can do a marathon in a subset of college sports, but not necessarily in your traditional division three, division two, division one programs. Typically don't go past 10 kilometers, at least not yet anyway, but that's an interesting discussion point too because I think it kind of sets the stage for where American distance runners end up in the marathon versus other countries where they sometimes start much earlier targeting that distance, but yeah, mostly 5K 10K stuff in college and then after college I explored longer distance running, longer, longer distance maybe. And it just was a logical, if you can call it logical, a logical move was to go into ultra running eventually. So it's kind of how I got into that.

Geoff

I presumed that you're racking up distance, and you realize, okay, I'm a decent marathon runner. Okay, this is handleable. I want to do a 50K I want to do a 100K. Okay, let's do a 100 miles. Where were some of the key benchmarks or checkpoints as you went on to be a world class ultra runner?

Zach B.

After college, I kind of focused it on just building up my aerobic base more or less, or my volume. I got intrigued by a high mileage training plan, if you want to call it a plan. At first, it was just doing a lot of kind of moderately low intensity runs at a high volume and just to kind of keep interest, I would jump in marathons or put marathons on the schedule, but I never really did what I would consider a well structured marathon buildup, where I went through the full phases of training in a way that I would be really faithful in the approach producing my fastest potential time. But I did a few of those before I jumped on my first ultra marathon and that have done them since then, as long hard workouts in preparation for a longer ultra marathons.

But I would say relative to my college experience, the marathon seemed a lot more interesting to me than say the 5K or the 10K, and that definitely bridged the gap between those traditional collegiate distances, and then doing my first ultra marathon, which is actually a 50 miler. So, I've done some 50Ks as well, but I actually did 50 miler first, and I lived in Wisconsin at the time, and I kind of stumbled upon the fact that there was actually a 50 miler in the state. I had no clue at the time. And when I saw that, well, I think I was 24 at the time. And my first thought was, "I'll do this one just to see what it's like, but then I probably won't do another one until I'm like 30."

And I'm 33 now, just so your listeners know. But yeah, so then I did that and I thought that was such an interesting experience. By that same time next year I was kind of all in and I was starting to do training for ultra marathon specifically, and being a little more specific about my training and periodizing things a little more versus just going out there and running along the mountain every day or whenever I felt good enough to do that.

Geoff

When did you realize that hey, I'm not just a serious amateur pseudo-professional long distance runner, hey, I could be the world's best.

Zach B.

It took me a little bit of time probably to realize the depth that there was in ultra marathon running, in terms of just the variety of events you could do. My introduction in was just trails, and I guess my thought, naively as it may have been, was that ultra marathons are just more or less done on the trails for the most part. And in North America that's a pretty big majority of the ultra marathon running. Which is interesting because when you look at the history of the sport in North America, it actually was the opposite if you go back further, the road and the flatter stuff got a lot of momentum. The trail was this really tiny, almost unheard of community.

Geoff

So like the Hard 100?

Zach B.

Yeah, the Western States and those types of events.

Geoff

So I think probably, if folks have listened to David Goggins or Jeff Browning who we work with those trail races, so I guess that might've been one route, but it sounded like in the history of the sport it used to be more flat and track based and there was some resurgence of interests are on the trail and road running?

Zach B.

Yeah. And you can even go back into, I think, the late 1800s, they would do like six day events and timed events in Madison Square Garden. And I think it actually got fairly popular for awhile, where they'd have a lot of people out there and there was a whole lot of other stuff going on. It was almost like a circus and there would be betting on runners and things like that. So it's kind of interesting to see some of that stuff.

But for me, I kind of stumbled upon this idea or this principle of specificity of training. And when you get into distances as long as a hundred miles, terrain and environment and weather play a huge role for that specificity. Because if you're better prepared for a specific weather or a specific terrain, it just compounds itself over the course of a hundred miles. And you know, I jumped into some flatter road type ultra marathons near the end of 2013, and upon that kind of introduced me into this event in Phoenix called the Desert Solstice Track Invitational.

So the race directors for that actually reached out to me and asked if I wanted to come do it at the end of 2013, and I was interested, because I'd actually just saw that there's a guy named John Olsen who, at that point, had just broke the American record for a hundred miles. And he was also the first American to go under 12 hours for a hundred miles. So I had just done a road 50 miler a few weeks earlier, and ran five hours and 12 minutes for that one. And my thought was if I can do 50 in 5:12, I can probably go through 50 during a hundred miler in 5:45, and then hold on for dear life and squeak under John Olsen's time. So, that was kind of my goal on that day. And I ended up running 11 hours and 47 minutes, and it took about 12 minutes off his time.

And that's what kind of got me really interested in, well how fast can I run a hundred miles when I'm really hyper focused on peaking for that specifically?

Geoff

So you weren't even training for world class, record level performance, but you kind of sized it up and you're like, hey, this is within my capacity. If I just go for it, I could be close. And you just rolled into it, and then you just started doing it.

Zach B.

Yeah, it was actually funny. I was actually in really good shape that year because I was training, I had one the Tussey Mountaiback 50 mile, which is the road 50 mile championships, the prior year in 2012, so my plan that half of the year was to go back and try to win it again. And I went back, and I ran a faster time on a slightly more difficult course, but I lost first place and got second by about four minutes to a guy named Matt Flaherty who is a solid runner himself.

So I kind of had this mixed emotions about it, where it was like, okay, I ran faster than I did last year, I went under the previous course record, but I was second place instead of first place. So I didn't really know how to feel about that. But then the race that I ran the 5:12 at was actually like 13 days later, I just kind of jumped into it randomly and that's when I think I kind of connected the dots, as to my training had gotten me very, very prepared for flat road or flat track type stuff, and that if I were really going to maximize my performance, it would benefit me to go to a race like that, so it matched my training.

And some of that happened just because my roommate at the time was one of my old college friends and teammates and he was training for a marathon, so we would do some speed workouts together and stuff. So I got in pretty good shape just from running a lot with him and doing some of that stuff. And that kind of got me to that race in 2013 and maybe I accidentally put together a really good training block.

Geoff

Yeah, interesting. I want to talk about nutrition a little bit, but perhaps to give folks who have a little bit of amateur running experience like myself. What does a typical volume per week look like? I mean, you're doing like a hundred miles a week. I have no idea how to train for a hundred miler.

Zach B.

I mean, you see so much variety. You can see people with what I would consider relatively low volume approaches to it. I personally like a higher volume approach. So if you look at just my running after I got out of college, or for the last decade or so, I basically have averaged about a hundred miles a week. I usually range between 5,000 and 5,500 miles in a year's time. So it can be a little above that sometimes, or right at it, or a little below it. But it comes out to about that, a hundred miles a week on average.

And within that, you have phases of the year where you're doing less and phases where you're ramping up. So when I peaked for this last a hundred mile 12 hour effort, my key training phase was this four week block where I had three buildup weeks and a de-load week. And a de-load weeks just where you kind of reduce volume and intensity. And that was like about 130 miles, 150 miles, a 75 mile week and then another 150 mile week. And that's kind of what a peak training block would look like when I'm really getting in a good spot and training and both physically and mentally really motivated to go after something.

Geoff

And internally within that week, are you doing a couple of long, 20, 30 milers and doing 3, 4, 5, 10 milers? How are you splitting up the volume?

Zach B.

Yeah, I'm usually backloading it a little bit to that Saturday, Sunday, and doing at least a relatively long run on one of those two days, and then a longer long run on the other. So I had a couple of weekends where it was like a 20, 30. I had another weekend, I think, that was 28 and a 27. And I'm trying to specify it as close to the course too. So being that this last one was on a track, I was just doing it on this like 400 meter dirt track near my house. And it is interesting, because I live in Phoenix, Arizona. So you know we were still in the thick of summer, so a lot of those runs were ending above a hundred degrees and it's both good and bad, I think. You're dealing with the monotony of running on a 400 meter loop, but when it's that hot it's not the end of the world I think because then you can just have your cooler sitting there and you can grab more water and cool off. You have ice and stuff right there for you. So it makes it a little easier logistically at least.

Geoff

Well at least you planted a seed there, which is the mental game of doing such a long endurance sport. And I think that's something that I think about a lot. The mental state, the mental game of doing something like this. So let's plant a seed there to talk about that. But before that I want to talk about nutrition. So we have a good understanding of, okay, your trajectory as a runner, as you're scaling up the volume and realizing, hey, I have a potential to be the world's best at these types of a hundred miler range races. But on the nutrition side it's quite interesting, because probably as you were being taught and coached through college, the dogma is carb load, carb load, you know, shoot sugar gels and carbohydrate gels as you're doing these races. And you're well known to be primarily filling with a ketogenic, or a low carb, high fat protocol. Can you talk us through how, why did you stumble upon some of the ketogenic principles and how you started experimenting?

Zach B.

My exposure to it was almost accidental but very well timed, when I look back at it. I first got interested about eight ago and one of the reasons I even found out about it was, when I was doing some of my training, I started feeling a little guilty about how many hours I was spending out there running. And I thought, well how can I add to that experience? So I started listening to podcasts while I was running, so I could at least learn while I'm doing it, not feel like I was just spending 20 hours a week sometimes running and not having anything else to report back about. And that kind of gave me the idea that even existed, a ketogenic diet, or a high fat low carb diet.

And ironically enough around that same time, I noticed that when I was doing my high level training and racing relatively frequently, it was just very difficult to manage sleep, manage energy levels over the course of the day. And those were kind of red flags to me, in the sense that I'm in my mid twenties, I'm supposed to be as strong as I am in my life. And here I am sleeping worse than I did when I was younger. I was on a roller coaster energy-wise when I was at work, and you're just kind of tied to that nutrition, you'd be eating basically all day long to sustain a big training load and work and all that stuff. And it just didn't seem sustainable to me.

So I was in a bit of a crossroads because I knew that the training had a role in that. I could have probably gotten away with my nutritional plan had I not been running as much as I was, but I was enjoying that. Like I wasn't miserable running, and I wasn't miserable racing. So I was hesitant to kind of give up on that component right away, without exploring some other options.

So the other logical option to me was, let's see if I can manipulate my diet a bit and deviate away from what I would consider a very well-formulated high carbohydrate diet. I wasn't eating a bunch of junk food or anything like that. It was very much what you'd expect someone who is interested in nutrition and reading the literature on sports nutrition for endurance athletes, that 60, 70% of your intake coming from carbohydrates, the fruits, vegetables, whole grains, that sort of stuff.

And basically what I did then is when I got to the end of my season that year, I had a little bit of an opportunity where I didn't have any real focused training for about a month. So I decided I'm going to try this now and see how I feel and if worst case scenario it doesn't work, and I just deviate back, then at least it's not interrupting a big block of training I'm doing preparing for a race.

So the biggest eye opening thing for me was once I got going into it, a couple of weeks into it, I started sleeping through the night again. So instead of waking up three, four, five times a night to use the bathroom or waking up wide awake and having to just restlessly lay there for 30 minutes before I'd fall back asleep. Just like in high school and college I'd go to bed, and basically sleep through the night, wake up eight, nine hours later. So that was a really big indicator to me that there's something to that or there was something in the way my nutrition was behaving with my body, before and within the context of a high fat, low carb diet.

Geoff

And it sounds like you also pretty rapidly keto adapted, right? Because I think a lot of people that are transitioning from more of a carbohydrate driven metabolism to more of a fat driven metabolism, they'll have the keto flu, or they'll have some lower performance or restlessness. But this might be due to the fact that you probably were dipping into a ketotic state as you're doing these long races and you're maybe just a little bit more fat adapted from your exercise load. That made it easier transition. I'm just curious in terms of your transition there.

Zach B.

You can definitely move your level of fat adaptation just through training. The reason that that's not an excuse in my opinion would be, you can move the needle a little bit with that and there's probably an ability to other to move the needle quite a bit with that, but it's not nearly as much as you can move the needle when you're treating your nutrition with that as well. And we saw that in the faster study was Volek, 2014, and what they did, and the reason I find it interesting is, they took a 10 person high-fat cohort and a 10 person high-carb cohort, and they made sure that both of the groups were highly trained athletes. So we could basically assume that they had maximized their ability to improve fat oxidation through training. None of these guys were off to college. None of these guys were unfit.

So when they did the study, the high-fat go heart was burning well above textbook levels. Before that you'd look in the textbooks, and you'd be like, if you're a freak, you might burn 0.9 or maybe 1.0 grams per minute of fat. Whereas I think I produced like 1.56 grams per minute or something like that, and I wasn't the highest. There's guys who are in the 1.8 range even. So you're looking at like a 50% improvement in that.

Geoff

You were a subject in that study?

Zach B.

Yep. Yeah.

Geoff

That's super cool. I got confused with the Nova study versus the Faster study. But yes, a lot of people cite that study, so that's cool. I didn't know that you were a subject. Very interesting.

Zach B.

At that point I was convinced enough that what I was doing was working for me at least. So to get kind of the tangible numbers to say, okay, this is what's happening was useful for me. And the other thing that I found really useful was it also showed me that there is a bit of wiggle room there. It's not all black and white. You see this, sometimes people say, "Well if you're going to do a ketogenic diet and make it work, you've got to be strict, and you've got to be strict 100% of the time.". And that may be true if you're using it for what we were chatting a bit about before, for therapeutic reasons, for something like epileptic seizures, type two diabetes and all that sort of stuff. But when we're talking about athletes who are metabolically healthy, I think there's some flexibility there, and it becomes less of a black and white, all fat or all carb, and more of a sliding scale, where how far do you want to slide that scale over towards fat or how far do you want to slide it over towards carbohydrate?

So I like to say, I'm aiming to be as fat adapted as I need to for the event I'm training for, versus as bad adapted as I possibly can get. I mean there was a washout period where they wanted us to make sure we were at 10% or lower carbohydrate intake, which isn't too difficult because that's about what I average over the course of the year, when you figure in my lowest carbon takes and my highest carbon takes combined. But I knew in the two years before that I was doing phases of training where I would flex my carbohydrates up to maybe around 20% or even sometimes a little over that if it was a really big session. So knowing that I was able to do that and still be fat-adapted to the rate I was was encouraging for me that I was kind of on the right path, and it just gave me a little bit of info into how I can kind of structure things going forward.

So yeah, that kind of highlights I guess the rest of that story a bit. I did that kind of four weeks of an uninterrupted phase where I was really strict. I did notice a little bit of a performance dip in those first four weeks, but it was a non-factor because I was just running basically just some off-season miles, more or less.

It was interesting though because I'd go out for a run and I'd be like, "Okay this feels like a pace that I would be around a seven minute mile." Then I would look at the watch at the end, it turns out I was running an 8:30 pace or something like that. But after about a month ... and I had some runs in the middle of that too that were right on point, so it wasn't even an everyday thing. But after about four weeks, that basically normalized. So then it just became a puzzle to solve that was like, "Okay, now what happens if I stay that low all the time?" when I reintroduced some real specific sessions that are more short interval, or VO2 max based, or threshold running type paces.

That's when I started to kind of see where there was maybe a little bit of wiggle room for someone training as hard as I am or maybe you could say a lifestyle component where the whole like 30, 50 grams a day is more applicable for someone who is leading a more traditional lifestyle, or they're going to the gym a few times a week, or they're dealing with something therapeutic, versus someone who's a highly trained endurance athlete. I think that window shifts closer to like maybe 100, 150 grams a day. Then you can also ... I'll flex up above that sometimes, too, but I'm usually balancing it out with easier recovery days where I don't need it.

The way I try to describe to people who are kind of new to it and are trying to wrap their heads around the whole thing is I say like, "Just think of the normal food pyramid, like the macronutrient ratios you're likely going to get from something like that, and then just kind of flip it on its head." So I wouldn't follow a high carb diet and eliminate fat altogether, but if I'm following a high carb diet, by default I'm going to have to be eating relatively modest amounts of carbohydrates, modest amounts of protein, and then that foundation is in fat.

I think that makes a ton of sense when we're talking about events that are a hundred miles in duration, because your race pace intensity is very low relative to some of those faster workouts that are going to be maybe more specific to like a 3k or a 5k distance.

Geoff

Or you're not throwing up weights, they're not doing like a CrossFit, a high intensity interval training type of an exercise for competition. But I think you articulate the nuance quite well. Something that's referenced, something that I wanted to just clarify within the community ... because I think within the nutrition Twitter space, I think people are very dogmatic, like, "Okay, we think carbs are evil. Don't eat anything," or like, "Fat is evil. You're going to get a heart attack if you just eat a lot of fat."

I think you put it quite nicely. For folks with metabolic syndrome, they are actually quite metabolically inflexible, so they likely do need to be more strict with their macro ratios. Okay, you want to constrain more tightly. But as you are going towards a healthier side and have metabolic flexibility, your system literally can handle different substrates just as efficiently. Then for certain types of performance attributes, you want availability of all the different pros and cons of each substrate for what you're doing. I think essentially for a sporting context, well, sometimes you do want a little bit higher carbohydrate, you do want to maximize your glycogen repletion after a long workout. That's where you might want to consider adding a little bit more carbohydrate.

Zach B.

Yeah, one of the things I find really interesting that I've kind of learned along the way, too, is it seems like there's no more nuance or more thought in kind of the time between sessions. So if I go intense enough that my body essentially fails before my fuel substrate fails, then I just can't drive energy demand high enough to deplete my muscle glycogens or my muscle glycogen and liver glycogen. So in a scenario like that where you're likely not going to come back and do another session like that until the next day or maybe even further, there's plenty of time to replenish the relatively smaller amounts of lost glycogen through fats and proteins.

Versus a training plan like mine where I might go out in the morning and in two hours with like 30 minutes at threshold, and then four or five hours later go to the gym and do some strength work and maybe an easy second jog or something like that. So that window is so tight between sessions, that volume is so high, you're just not giving yourself quite enough time. It's this weird balance where the intensity is just high enough that you can start dipping into your glycogen stores in a significant way, but just low enough that you can do loads and loads of it. It's really kind of a gray area I think, and it's an area where sometimes I question "Are humans really supposed to be doing this?"

Geoff

But I think what you're describing is really the future of sport performance. You have to think about the actual physical training and the technique in conjunction with your nutrition load. That's the one, two punch. You're exerting energy through exercise, you're intaking energy through your consumption. I think I would say in the previous paradigm of sport, you think about nutrition off to the side and you think about your training off to the side. You might cycle your training, and maybe if you're not sophisticated, you only cycle your nutrition. But I think where more and more sophisticated athletes ... and it sounds like you're very much sort of the cutting edge here ... you very much integrate how you think about your energy intake against your training load and you'll periodize both synergistically.

Zach B.

Yeah. It makes sense when you kind of just scale it down to what it is, where my lifestyle as an extreme endurance athlete varies significantly depending on where I am during the season or the year. So for me to plug and play a very exact nutrition plan day in and day out every day of the year wouldn't make as much sense as having it kind of flow, like you said, with the plan itself. So if you're doing periodized training and you're doing significant buildups and then significant recovery phases and things like that, I think there's a lot more you can do from a variability standpoint when it comes to both the macro nutrients as well as just the general energy intake.

Geoff

So maybe I think my conclusion from this thread here is that I understand why some people on Twitter or social media are pretty dogmatic around keto is good, and I think you probably need that counter swing to pull people away from the current FDA food ... or USDA food pyramid where it's like, "Eat 70% of your calories from carbs." I think there's good reason why you're seeing obesity metabolic syndrome rise, because you're feeding a lot of people processed, refined carbohydrates. So I think there is some kind of balance needed to say, "Hey, no, fats could be useful." Carbs are not necessarily great, but I think once you pass that initial, let's say, hard reshift in thinking, then I think you can potentially start reintroducing some nuance.

So folks who are listening to the program that are considering low carb, high fat, or ketogenic diet for therapeutic, or weight management, or body composition, or metabolic syndrome use cases, you probably need to be strict, because you need a hard shift and reset your metabolism. But as you get back on the healthier track and start looking at doing things like what Zach is doing here trying to win a hundred mile races, then you can get a little bit more nuanced, reintroducing carbs strategically. Which I think is important just to say that there's a couple different levels of the conversation. We each are at different stages of where we're are in our metabolic health and we need to engage at the right level before saying, "Hey, I want to do what Zach's doing, but I'm not training like what Zach's doing."

Zach B.

It's kind of funny, because you see that type of mentality in a lot of different areas in life, too. It's not necessarily a bad thing, it's just something I think people need to be aware of where ... when I look in endurance training, too, you do something that generates a little bit of awareness, whether that's something like what I did or even just in your local community. Maybe you have a group of friends and you just ran a 5K or you lost 20 pounds that you needed to lose, and you see your friends see that, and they're like, "Okay, well, what they're doing is working. I need to do exactly what they're doing." Really it's like, "Well, you need to backup and look at what were they doing to get to where they are and make sure you're doing all those initial steps, too, along the way.

Even for me when I'm working with folks who are interested in a kind of a high fat, low carb or ketogenic style diet, we're looking at a lot of different variables even as far down as to well, "How important is optimal race performance to you versus just your general wellbeing?" and things like that, and your general interests, and what you want to be eating. A lot of times even with the people looking for pure performance, we're going to spend a good month or four to six weeks even going pretty strict keto in the beginning to kind of reset that metabolic switch a little bit, so it's just a little bit faster maybe to kind of turn that switch over. Then we can always bring the carbs back. The body seems to be very efficient at turning back to carbohydrates if you do decide to reintroduce them. So to me that's a lot less of an issue.

Geoff

Yeah, I think that's where I think we should all should be optimistic. Doing N=1 experiments with myself, looking at fasting insulin, fasting glucose, you don't need to be doing a ketogenic diet for a year to see pretty profound biomarker changes. It sounds like ... I don't know in terms of fat oxidation how quickly can you ramp from 0.5 grams per minute to something to your rate of like 1.5 grams from it. Maybe you do need to be keto and training a lot to get to that kind of level of fat oxidation, but I'm sure you can go from 0.5 to 0.7 relatively quickly if you just do a little bit of fasted training and reduce carbohydrate intake.

Zach B.

Yeah, and I think ... because you mentioned a Louise Burke study, because she did that three week study with 50 kilometer race walkers. I want to say the folks doing the high fat on that, they were actually putting up pretty high numbers by that three week point in time. So the interesting thing about that is I would look at that from a performance standpoint.

I'm not really sure what that study would indicate, because I'll tell you this, it's pretty common knowledge within endurance sport and sport in general that you don't overhaul your diet three weeks before your peak performance. If I were an Olympic athlete and I had the five kilometers in the Olympics three weeks from now, the last thing I would be doing is flipping my diet completely on his head. So I'd have to look at that study to see more nuance out of it. My guess is it's saying what it intended to say, and a lot of people just maybe extrapolate out from it more than what it's intended to say or do.

Geoff

Yeah. To give context to the listeners, I think Volek and Phinney are the key thought leaders around in academia around ketogenic performance. I would say that Louise Burke's ... I think the Supernova study was like, "Hey, maybe it might increase fat oxidation, but it doesn't increase actual end performance." I think the counter argument, I think the point that you bring up as a student, which is that you're not expecting to match your previous PRs if you change your diet completely and try to shift your metabolic state completely from glycolysis driven to ketosis or lipolysis driven in three weeks.

Zach B.

Even if we do look down the road and say like, "Okay, this person's following that for a year or two," I would suspect a lot of them would have the same experience I did, which is the strict keto isn't necessarily ideal for peak performance, but that doesn't mean that you have to go right back to high carb. You can kind of do something more similar to what I do with that periodized kind of carbs sneak in there. That's where I'm interested in, I'm interested in kind of that middle ground between the two. Hopefully some funding goes towards some of that stuff down the road and we see some more research and some studies done, but either way you can do your own N=1 experiment if you're interested enough.

Geoff

Someone's got to make some sort of catchy name for that, because I think what you're describing is similar to what I implement personally, which is I would say that I have a low carb ketogenic base, but I will add in carbohydrates ahead of certain of high intensity weight lifting workouts. Or if I'm doing like a long bike ride for an afternoon, I will use carbs if I want to be maximizing performance, but also do some fasted training as well and just blend it together.

Zach B.

Yeah, and it's interesting, too, because I think when you look at what I'm eating, I hardly see it as restrictive. Because the knock on a strict ketogenic diet or if you're going to be like a zero carb diet is people will look at and be like, "Well, I can't sustain that." Then the numbers probably reflect that, too, in terms of people starting and stopping, or falling out and feeling like they failed, versus staying the course. When you get into that high fat, low carb where you're flipping it is on its head but not going quite as low as those therapeutic ketogenic levels would be at, you have a little more wiggle room there so it doesn't feel as restrictive.

I always getting a little bit of a kick out of that, because every once in awhile someone will say like, "Well, I could never do it, because I wouldn't really eat this anymore," and they'll send me a picture of this meal. I'll look at the meal and it's like, "You know, I could actually eat that. It wouldn't ruin my plan, I would just be maybe a little more strategic about when and where I ate it."

Geoff

Exactly.

Zach B.

So it's all individualized anyway at that point anyway.

Geoff

Exactly. One thing that I think is interesting that I would say is a popular sub-thread from the low carb community is carnivore. I know that you do a podcast with Sean Baker who's been on our program who is quite the carnivore proponent. Curious how heavily animal based are you? How do you sort of take all the recent N=1 anecdotal stories from carnivore?

Zach B.

I think it's really, really fascinating, especially when you start to look into where it's being more heavily researched versus just the anecdotes we see on Twitter and we see online. Because I think the first thoughts of most people is just, "Well, this is just a bunch of crazy people that decided for whatever reason ... maybe it's because they got mad enough that the vocal vegans that they're going to go completely opposite."

Versus like there's a group out of Hungary, the Paleomedicina group, I'm not sure you're familiar with them, but it's a guy, Dr. Csaba Tóth and Dr. Zsófia Clemens. They're doing a ton of fascinating research with animal based diets to help people with just really, really bad metabolic syndrome and digestive issues. They get way more technical, but for simplicity's sake it's basically leaky gut where people, they've destroyed their digestive system for whatever reason, and they're seeing some just really mind boggling results when they're putting people on this like 82%, 18% fat to protein ratio, essentially zero carb diet on animal-based products. It's pretty regimental, but these are people who are ... they're suffering.

Zach B.

It's amazing what people are willing to do when they're up against it to that level.

Geoff

It's like Mikhaila Peterson's autoimmune issues. You are depressed and want to kill yourself level and you'd try anything.

Zach B.

Yeah. One thing I find interesting, too, is just when we look at some of this stuff, you can kind of look at like, "Well, what am I eating? What am I trying to do? Where am I at? Where do I want to be?" I don't think it always has to be a like, "This is what I'm going to do now, I'm going to do it forever." I think with a lot of the carnivore movement, what we'll see is we'll see people kind of get healthy doing it almost as a real strict hard reset or a real strict elimination diet, and as they do kind of start to heal their ... give their body a chance to kind of recover, they'll start reintroducing some things.

I find it really interesting when you look at some of the ways indigenous tribes prepare their food, whether they're closer to plant base or closer to animal product base or somewhere in between. What we don't see is we don't see these tribes eating things in the state that we see them in the grocery store. One guy said it really well, I think it was Ben Greenfield who said, "It's smart food." You can look at something like bread. Well, you can have white Wonder bread or you can have a really well-formulated sourdough bread. The way your body reacts to that and the way we break down some of this stuff is different depending on how we prepare it. So sometimes going back to some of these ancient traditions and looking at what they're doing to prepare the foods or to liberate the foods to make them more digestible for humans is really interesting to me. So I think we'll see some of that too where people start reintroducing some things in maybe a more traditional sense, that they don't stick to like a strict carnivore diet.

But I think we're learning a lot from that group and I think it's smart to keep an open mind about it. Ultimately I think it also opens up the conversation of, "Where are we getting these products from and how are we raising these animals?" I like to think that it will open up a conversation towards if we're going to be relying on meat as a staple in human nutrition, well let's look at what the way to do that would be that's regenerative or that's holistic versus something that's maybe detrimental. Introducing people to that so that people are a little closer to their food systems versus kind of 100% just separated from them.

Geoff

Yep. Have you personally implemented 100% carnivores? So for background, I did a couple of cycles of four to six weeks of carnivore diet. I thought it was quite nice, quite palatable, and that has informed my day to day to not be afraid of having higher meat content as part of my overall meals. But I think just on a practical basis, it's somewhat hard to eat only meat 24/7, but I think that over the last year, year and a half, I think that really opened my eyes around, "Hey, one shouldn't be immediately scared of all the headlines running red meats and associations with cardiovascular disease and all cause mortality," in that it caused me to really dive into the research and the studies and exactly what was there and what might be potentially confounding conclusions.

Zach B.

I think that's probably the point that I'm most interested about it, too, is ... So then some of it we just don't know, right? We don't know necessarily outside of anecdotes what happens when you go on an all meat diet or a meat heavy diet. So when we get more people doing this and reporting their anecdotes, that kind of forces us into the next step. Now we're going to start having case studies, and then we start looking into the epidemiology of it, and then we eventually start to get some random control trials and really look into see what's going on and kind of find out what is working and what's not working.

The one cool way to look at some of this stuff in general is it seems like there's always going to be a pro and a con to what you're eating. So you can look at someone who has a history of a certain disease in their family or they've had a disease or something like that for them. They may want to turn to a different type of nutritional plan, because they want to mitigate the risks for that particular thing that their highest at risk for. They may have a very low risk of some other things, so they can maybe incorporate things that would potentially increase the risk of that, because they're just balancing kind of that equation a little bit.

When we're looking at things like that, I think it behooves us to have options as opposed to here's one definitive mono way of eating that the government's going to say is the right way to do it. If you're doing anything different, you're risking yourself like ... Give us five options so we can kind of pick and choose and find what's we're going to work for us from both a sustainability standpoint that we can stick to and also to mitigate whatever things that are potentially risk factors for us as individuals.

Geoff

It's just obvious if you look at it from a genetics and baseline perspective and what your goals are. Zach Bitter has this genetic baseline and he wants to win 100 mile races, you should have a thoughtful diet and exercise protocol to help optimize that. For me, if I'm trying to optimize cognition and not get Alzheimer's and not get disease and this genetic baseline, it probably seems sensible that you have maybe a little different nutritional protocol for that. I think it's silly to say that, "Hey, every human needs the same diet," even though we have quite a bit of genetic diversity and we all have different individual goals that we want to optimize for. Again, trying to win a gold medal, that activity is probably pretty orthogonal to what you'd want to do to prevent disease or try to live as long as possible. You're just trying to optimize for very different end points.

Zach B.

Yeah. Nowadays, too, when we have availability to be able to see and follow basically anyone who was willing to put it out there now, you see these different goals and these different areas of focus, so there's no shortage of seeing where those differences kind of come into play.

Geoff

So one topic that I want to move towards is the mental discipline, the mental game of what it takes to do these hundred mile ultra endurance events. Again, I'm a very, very amateur ... dabbles in these types of endurance events. The longest run I did was a 30 mile run. The initial entry to that is pretty stark for most modern people where we're very much used to having some stimulus from our phones or devices every 10 minutes. And if you are properly training for these longer runs and doing a hundred mile run, you are by yourself for like 12 hours. Do you focus on anything? Do you just let your mind drift? What is hour five into an effort like this?

Zach B.

When I talk about endurance sport in general, I think the training, both physical and then the mental components are all there, no matter what distance you're doing. It just comes down to where you place them and where you focus more emphasis or less emphasis. So as you start pushing up in distance into some of these longer events like the hundred mile stuff, I think that mental component just gets a little different, where instead of being able to force yourself through an acute pain for a relatively short period of time like you'd get in a five kilometer race, now you're asking yourself to push yourself through the monotony and the self-doubt and the boredom and the gradual fatigue and the slow aching pain type of a thing.

Geoff

Yeah.

Zach B.

And it's almost like you have this mental reservoir that you're pulling from, so you need to be careful about when and how you're doing that. And you definitely want to go into a race with that reservoir as full as possible, because that's just going to give you more potential to push through some of those low points or those negative thought processes. So you highlighted it perfectly when you said the four or five hour part, because on my last particular event, that's a point in the race where I've been out there long enough where I'm starting to feel it a little bit physically, five hours of running is five of running, no matter how you skin it.

Geoff

Most people can't even stand for five hours. Right? Just think about that. When's the last time most of us have stood on our feet for five hours straight? You get tired from just standing and you're covering some big ground.

Zach B.

Yeah. So you get to that point and then if you think about it then too, you're like, "Okay, I'm feeling a little bit worn down. I feel like I've been running for five hours, but I got six or seven hours to go." So that's difficult in the sense that it's really tough to start wrapping your head around what you have left to do. So I think that point in the race you do find yourself, or at least I do find myself having to fight back a little more doubt. And then as I get closer and closer to something I can wrap my head around, you get a little more optimistic, it gets maybe a little easier, assuming the day's going well. If the day's coming off the rails, then sometimes the further in you get, the harder it gets because then you're just questioning why you're out there on a constant basis.

So for me, when I was at mid-forties, I was at that point where I looked at ... The unique thing about the event I just did is it's on a 400 four to three meter loop, so I can see my split basically more frequent than every two minutes. So to go back to what I was saying before about that mental energy or that reservoir, if I choose to watch my splits every lap, I'm probably going to exhaust my mental reservoir a little too quick. So some of it is just doing little mental tricks where I'm acutely aware of my pace and effort enough where if I give myself a few laps in the beginning to dial in the pace range I want, I can just cruise for a while and avoid looking at that and just get a rhythm going and let my mind wander a little bit.

But I'm spot checking because if I notice I'm drifting out either too fast or too slow, I'm going to want to recalculate or recalibrate that intensity and that effort to make sure I'm still in that range. And I got to that point around the mid-forties where I had been slipping out of my pace a little bit, going a little too slow. The thoughts start crossing your mind like, "Well, maybe I just don't have a PR or a world record performance in me today, maybe I should just settle down and take what I can get." You start thinking, "Well, 11 hours and 50 minutes would still be a solid day and then I can be fresher for a race down the road." And you almost have to say, "Well, wait a second. Think of how many hours and how many training sessions you went through to get ready for this particular opportunity. Don't let it slip away right now. Let's start to zoom in a little bit" and say, "Okay, in the next two miles, I'm going to get back into the pace range. I'm going to see how I feel at two miles before I make any rational decisions."

And then you can start to slowly turn things back from that negative self-talk to that positive self-talk. So I got myself into that position where I was back into my split range and then once I was in that, it became a little easier to say, "Okay, now let's just do a few more miles." And you start getting closer and closer to that point that I was explaining before where, "Okay, now I'm far enough into this race where I'm within the distance that I did my longest long run" or "I'm within the distance where my average of my long runs ended up at." And then you can shift your mind from "I'm out here trying to run a hundred miles as fast as I can" to "I'm just doing something I do on a weekly basis now."

Geoff

Yeah.

Zach B.

It's that momentum, spiraling that momentum back positive. And then for me, on this particular event, I'm pulling from past experiences too. There's things I did at this last race that I wouldn't have been able to do earlier in my career just because I didn't have the point of experience. And one of the biggest ones was I made an attempt at the world record back in 2015 at a event called the Desert Solstice Track Invitational and I ended up breaking the American record that day but at mile 80, I was on pace to break the world record. And I remember the race director told me, "Well, these are the splits you need to run at the last 20 miles in order to break the record." And I just couldn't do it. So when I think back of how many days between then and that race that crossed my mind where I thought, "You know, I had this opportunity, I was at mile 80, I could have done it but I didn't." When you think about that enough times, when you get yourself back into that position, you go to a mode of, "Okay, I'm not going to let that happen again." And you learn from that experience. You pull from that.

I wouldn't say it was a failure at the time. I broke an American record, I had my fastest hundred mile time ever so there was definitely positives to pull from that event too, but there was also things I could point to that are like, "Well, there's a spot there that I need to make an improvement. That's where I can grow in the sport." So then, getting yourself to where I was at at this last race, I'm just thinking about that a lot and just thinking about, "Okay, how much time did I spend getting ready for this? How much time did I spend learning from my previous stuff?" The incentive to take advantage of the opportunity, I think, gets greater and that helps out when you can spin it in a positive direction.

Geoff

I wouldn't say that the 2015 race was a failure per se, but it sounds like you took some of that learning experience, that sense that you thought that you could have done better as a way to push yourself. And I think it just reflects on a conversation that I had with Pete Jacobs who is a Ironman world champion, who is now shifting more towards a carnivore diet and coming back on his comeback. And he had an interesting comment around having a mantra of love, positivity, and it sounds like for you, you've pulled on different parts of negative and positive energy through different aspects of the race. So that's part of one of the questions, some clarification on it. Is that the way you think about it? Is there some times you want to have like, "Okay, I don't want to fail. This person said a mean thing to me. I want to prove that person wrong, screw that person." And then sometimes you think about all the positive things. That was part one of the question.

And then part two was, this is something that I've come to think about more is that, I'm just curious in terms of your world record breaking performance, would you describe yourself in a state of flow? Would you almost compare yourself to be in a meditative trance or state where if you had a brain scan of you during that race, would that brain scan look like a Zen monk who is just meditating? And I think that's an interesting thing I want to just maybe plant in the ground to talk about after talking about part one.

Zach B.

It's a balance, for sure. You want to go in with gratitude and you want to go on there being appreciative of the opportunity you have as opposed to being fueled purely by hate or purely by anger, but that's something you can leverage.

Geoff

But hate's powerful, right? It's like the dark side of the force, light side of the force, I mean, I think definitely there's some work that's from like, "Yo, this person made fun of me. I want to put that aggression into the exercise or into the event."

Zach B.

Yeah. You think about stuff like that. If you use it the right time, I think it can be very powerful. From my experience, I think if you start the race thinking like that, it gets a little difficult. But if you keep it in your back pocket and lean on it a bit when you get into the later stages, it gets a little more useful, at least for me anyway. And I wouldn't say I get a whole lot of negativity thrown my way for any reason really, but you still see it. People like to think and people like to speculate and I think that's one of the fun things about sports is people wondering about what if or that sort of thing. So when you have a race like I did in 2015 and then you make another attempt later and that one doesn't work out well, you do see sometimes people saying things like, "Well, maybe 11:40 is the fastest he can go." Or, "Maybe if he would have had a little more carbohydrate, he would have run 20 minutes ..."

Geoff

Yeah.

Zach B.

So that sort of stuff, but it's not necessarily a thing where it's trying to push someone else back as much as it is, "Thanks for that little bit of fuel, I'm going to use that." And most of the time I think it's harmless, but you hit it on the head there where I think when you can have that duality of being grateful to be there, being positive, trusting your process, believing you can do it and then also thinking, "Okay, I'm going to prove something here today."

Geoff

Yeah, that generally rings true to me in terms of keeping it positive and using some of the hate fuel in the pocket when you need some extra aggression. But I agree with you, I think if you start out angry, I just don't think you can sustain being angry for 12 hours.

Zach B.

12 hours is a long time to be mad, yeah.

Geoff

It's a long time. And then the second point, I think one of the things I've appreciated with endurance activities is that's I think it's a more effective version of meditation. And I think it's increasing in popularity that meditation, mindfulness is a big buzz word, but I think most of it is performance. I think if we're just sitting in a room for five, 10 minutes, I don't think it's enough. I don't think it's true meditation or what the goal of meditation is, which is clarity of focus or clarity of mind. And I feel like with endurance sport as the medium, it almost forces you to have that clarity of mind. So I think it's a much more efficient vehicle for me to get mental clarity and mindfulness. I'm just curious in terms of, especially for endurance sport, I feel like it's just as much mental as it is physical. Or at least that mental component is very, very strong. Do you meditate? How do you think about building up your mental discipline, your mental reservoir? Do you think about it in terms of reaching the enlightened Zen state that you see the monks talking about?

Zach B.

I think you're right. It's one of those things where it's hard to quantify and it's one of those things where you're like, "Yeah, I do wish that some machine hooked up to me during that race. You could see exactly what was going on."

Geoff

Yeah.

Zach B.

But you definitely get into these states and I actually practice them when I'm doing my long runs and it's like a visualization type of a practice as much as it is anything where, say I have a 30 mile training run scheduled for Sunday and I'm preparing for a hundred mile race, I go out there and I put myself in my mind at mile 70 and be like, "Well, what am I going to do at mile 70 if I'm given this opportunity?" So you've almost done a dress rehearsal in your head and you get these experiences that you can pull from during the race, so then when you get to the race, it's less about learning it on the fly and you can go into that state of flow and just reflect back on, "Okay, I know what to do here." And then just center that and just let it happen as opposed to try to force it.

And it's one of those things where I think it almost makes describing the event difficult because you get into those states and you don't really remember being in them so in the back of your mind, you know, "Well I was definitely thinking about something but I just can't recall it anymore." And then someone asks, "Well, what did you think about the whole time?" And you're like, "I don't know." Because you think of some things you do remember and you're like, "Well, was I thinking about that the whole time or was there stuff I forgot?"

Geoff

Yeah, when I just started out it's like, "Yeah, what do you think about it?" It's such a long time you're by yourself. But then as you get more experienced, it's like, "I don't know." You get into these flow states where you've just done it. Maybe it sounds super woo-woo to people that haven't done endurance activities but I think, for people that have experienced or tapped into some levels of this, it's a very real mental state that you are in that I think more people should try to tap into because I think it's an interesting human experience.

Zach B.

Yeah. When people ask me the question, "What do you think about during it?" My mind always goofily goes back to the movie office space when they asked the guy in there, Peter, they were like, "So what do you want to do with the rest of your life?" He says, "Nothing." So, "What do you think about during a hundred mile race or what do you want to think about?" "Nothing."

Geoff

Yeah.

Zach B.

So it is kind of interesting, you get into that state of mind where you're just out there and you know you're moving but you're not necessarily feeling everything you think you should be feeling. And it's weird because you come in and out of it, you're never in it the whole time. So mile 60, I might be very aware of what I might be doing. I might be thinking very much and I'm feeling like, "Okay, my left leg hurts a little bit, my right quad's a little more sore than my left one. Am I drinking enough? Do I feel thirsty?" or just thinking about a lot of stuff. And then all of a sudden, you get into one of those states and all of a sudden you're there and then when you come out of it you wonder, "Well, why did that last eight miles? Did my ankle not hurt? And my right quad not hurt more than my left one? I didn't feel as thirsty." So you know you're kind of in it, but you don't always know about it until you're out of it.

Geoff

I think that's the key thing that, at least, it's refreshing for me to hear, given that it's hard to maintain. Even the world's best person at doing this is not holding perfect Zen state for 12 hours straight, which is probably refreshing for amateurs like myself. Like, "Okay, no one is God-mode level mental 24/7 on." Is that something that you aspire to or do you even think that's approachable? Is that trainable or do you think that that's just human nature that there's going to be just a little bit of mental variation as you're doing something over such an extended period of time?

Zach B.

Yeah, I think maybe there's a process to improve it or to maximize it, I guess, is maybe a better way to say it, but I also think there's some times where sometimes it just works better than others and those are probably the times where you're going to outperform. And if you think about it in other sports too, like in basketball, you have someone who is just on one night and they're just hitting every shot they take, they get in that flow state. And then there's another night where they want to be in that same position every night, but then there's a night where they're not and they're missing every shot they take.

Geoff

Yeah.

Zach B.

So I think there is a element of just having it at the right place at the right time to a degree, but I think you improve your chances of having that happen if you do those dress rehearsals that I talked about in training where you know where you should be and how you should be doing at certain points and you've processed it in your brain, even though you haven't done it yet, over and over again during practice.

Geoff

That rings true to how I think about it as well. It's too complicated to understand exactly what triggers flow state or not, but to maximize the probability of consistently doing it, you probably just need to do the event again and again and again and just have a template in your mind of autopiloting. Then you just take a very comfortable state for you. Awesome. What's next? Maybe you haven't thought about what's next, but knowing folks like yourself and myself, once you get the one thing done, you're probably thinking about, "All right, relax for a little bit and what's the next world record? What's the next thing I can do?" Is there something in your mind that's exciting, post a couple of world records here?

Zach B.

Yeah, so the irony of the whole situation is, when I started the training block for the second half of the year, I typically divide my year into two halves, at least now that I'm out in Phoenix and I have access to such a variety of different trails to train in. One half of the year, I'll do more trail climbing, descending type stuff. The other half, I'll do more flat, fast stuff. And the first half of the year, I was training for the San Diego 100. So when I finished that, I was like, "Okay, I'm going to start doing my buildup for the flat part of the year." And I picked a race that met my timeline really nicely, which is the Spartathlon in Greece. Then, after I had already put all those pieces together, I found out about the event I had just done and it was such a unique opportunity, I didn't want to pass up on it. So I thought, going into the training block, worst case scenario is, I can just use this as a tune-up run for the Spartathlon. As I got through the training, the flat fitness came back so fast and I had such good workouts that my mindset going into that race I just did was, if I feel good, I'm going to go forward. If not, then, it is what it is and I'll be ready for Spartathlon at least.

So things went as well as I could have expected, but I still have this race on the schedule to do over in Greece, which I'm actually leaving for this Saturday. It's in a little more than a week. It's 153 mile race. It goes from Athens to Sparta on a rolling hill, paved and gravel road. So we'll see how that goes. Five weeks recovery is a little tight for something like that in my opinion, but the Spartathlon is also a race I feel like I'm probably going to do a couple, if not a few times in my career, so if nothing else, I'll at least be able to get to do a repetition of the experience out there and figure out what the course is really like and put together a more solid, more prepared plan for the next time out there. But with that said, I do feel pretty well recovered. I'm going to lean on some fitness that I had before the last race, hopefully, and see what happens.

Geoff

Awesome. Yeah, good luck next week. And then one of the questions I always like to wrap these conversations up with, and I'm curious to get your take because I think you have so many different interests here is that, what is some of the most interesting scientific questions that you'd like answered? If you had infinite resources, Guinea pig populations, whether you wanted to look at ultramarathoners or just average Americans, you can put them in a metabolic ward, you can make them do thousand miles runs. What would you study? What would you structure it? Maybe a couple of questions.

Zach B.

I would want maybe a more specific, what would be the primary nutrition plan for the varying distances as opposed to, "Well, this is what works for endurance" or "This is what works for power lifting. This is what works for sprinting." Can we figure out what's the difference between the 50 kilometer and the hundred mile or then the six-day or something like that, which I think opens up a ton of windows.

Geoff

Yeah, they're pretty damn different things.

Zach B.

Yeah, yeah.

Geoff

A 5K is like a freaking sprint to you, but at this point, right, versus a hundred miler? I mean, that's a completely different thing. It's like a one rep max deadlift versus, okay, do a hundred deadlifts in a row.

Zach B.

Yeah.

Geoff

Those are very different types of performances.

Zach B.

Yeah, completely different systems so it is interesting.

Geoff

Okay, so you'd want to get more fidelity and nuance around the different lengths of race, where I think, right now, and I would agree with you, it's just like sprint and then long distance and long distance is anything from 5K to 500 miles.

Zach B.

Yeah. Yeah.

Geoff

Cool. Well, thanks so much, and then good luck with the Spartathlon next week or in a couple of weeks. Really good conversation. I'm excited to follow your progress as you keep exploring the limits of human forms here.

Zach B.

Yeah, well, thank you so much for having me on. It's been a lot of fun.

Geoff

Cheers.