Zach Bitter: Fat Adapted Endurance Training And How To Break 100-Mile Records

I first met this episode’s guest, elite professional ultra-runner Zach Bitter way back in 2016, back when he was first starting, getting himself on the map and dreaming of a career in ultra marathon running—and now look at what’s happened to his career!

Besides being the national 100k champion and holder of many other titles and records, Zach was an early pioneer in the ultra running scene, and is known for his success at pushing the edges of human performance as a fat adapted endurance athlete. He also hosts the wonderful Human Performance Outliers podcast.

To get a sense of the level he’s performed at, get this: he set the world record in the 100 mile run (on an indoor track) when he caught the time of 11 hours and 40 minutes. That is an average pace per mile of 6:48. The next time you run, try to see if you can run a 6:48! He also set an amazing record for 100 miles on a treadmill in 12 hours and 18 minutes. You’re going to learn so much from Zach in this show as this absolute endurance machine talks about his background and training, his take on minimalist footwear and the reason why he actually still wears “normal” shoes (and how often). You will also hear him discuss his revolutionary training methods, what he does in order to race more efficiently and recover faster, and much more! Enjoy the show and connect with Zach via his website, linked below.


Brad reviews conversation from 2016 with Zach Bitter when he was just getting started in his career in ultra-running. [01:05]

Zach Bitter’s amazing fetes include setting a world record in the hundred-mile run on an indoor track. [02:11]

Zach and Brad are both fans of minimalist shoes, but they intersperse wearing those with “puffy” shoes. [04:02]

The big goal of the Faster Study was to find out what is the difference in energy oxidation rates between carbs and fats. [06:06]

You can get better and better at burning fat and your’re gonna need fewer ingested calories. [08:10]

On the Western States 100-mile race Zach ate very little fruit and drank only water with electrolytes. [10:23]

In the beginning in the ultra-scene, Zach was carb fueled.  What changes have you noticed? [12:46]

As Zach transitioned his diet, he slowed his training a bit. [16:03]

The experience of oxidative stress comes from consuming the carbohydrates. [20:09]

When restricting dietary carbs, it has a potent anti-inflammatory effect known to be at the level of the most powerful drugs. [24:20]

Zach lowers the carb intake to get better performance. [25:19]

Has there been a change in the ultra-scene towards that adaption? [30:39]

What tips does Zach have for runners looking to make the transition? Be patient is the first one. Get good sleep. [33:48]



Brad (00:01):
Welcome to the Return of the Primal Endurance Podcast. This is your host, Brad Kerns, and we are going on a journey to a kinder, gentler, smarter, more fun, more effective way to train for ambitious endurance goals. Visit Primal to join the community and enroll in our free video course.

New Speaker (00:25):
Hey listeners, I’m so pleased to introduce my conversation from years ago, 2016, with Zach Bidder. And what’s so cool about that is that he was just getting going back then. He took off from his substitute teacher gig in Sacramento, California to meet me in person up at the finish line of the Western States 100 mile run in Auburn. He’d already had some great performances back then. He was getting known as a fat adapted, keto adapted endurance athlete. So he was one of the early pioneers in that area, in the ultra running scene along with two time western states, champion Timothy Olson.

Brad (01:05):
But Zach was just getting on the map dreaming of a professional career in ultra marathon running, which really didn’t exist back then. But look what’s happened to this athlete’s career progression. It’s absolutely been astonishing. And with the progression of his own career, we have seen an incredible progression in the popularity and the sophistication of ultra running as a sport. So that’s great for the leading athletes like Zach because now he’s able to make a legitimate full-time career out of it, which he deserves to training at that level. I mean, these guys are training as hard or on a par with any other athlete in any sport in the history of sports. I mean, you cannot believe the training load, uh, in an impact sport like running the Tour de France. Guys certainly train hard and are on the bike all day, but running a hundred twenty, a hundred thirty, a hundred forty miles per week in and week out, and then competing at the hundred mile competition level, or even those 200 mile longer crazy events, it’s pretty amazing.

Brad (02:11):
The great thing about Zach is he’s very knowledgeable and formed well spoken. He’s a true enthusiast of peak performance in every way, and he has a great podcast. So I strongly encourage you to go over there and listen to the great content that he puts out on the Human Performance Outliers podcast. But to get a sense of the level that he’s performed at over the years as he’s progressed with his career, he set the world record in the a hundred mile run. This is on an indoor track running laps and laps on an indoor track. He clocked a time of 11 hours and 40 minutes to run 100 miles. That is an average pace per mile of 6 48. I want you to go out on your next run. You could put your smartwatch on or go to the track and run four laps and get a sense of what it feels like to run a 6:48 if you can even run a 6:48 <laugh>.

Brad (03:08):
How about a a 03:24 for half a mile? It’s moving, it’s clicking along. And he did that for 100 miles. He also said an amazing world record of 100 miles on a treadmill in 12 hours and 18 minutes. Imagine running on a treadmill next time you complain about your boring workout cuz you had to hit the treadmill for 40 minutes cuz it was icy and snowing outside. Think about Zach not only staying on the belt for 12 hours, but running just over seven minutes per mile over and over and over. Absolutely phenomenal endurance machine. So we get to hear from him about his background, his philosophy about training, and you’re gonna learn a lot from this guy. One takeaway that I had from him in a recent conversation when we were talking about the popularity of the minimalist shoe movement, I’ve been such a big fan for so many years.

Brad (04:02):
But he had a great insight that I’ve implemented into my own training, which was that he’s a big, uh, fan of minimalist shoes as well, but he likes to rotate in cushy shoes now and then to give his feet a break and kind of transfer the impact load to in a different manner when you’re wearing the puffy shoes. And so I went out and got myself the puffi -est possible shoes I could find, and I used those for my 13 hour hike on the Cactus of Clouds route in Palm Springs. It was a 22 mile epic adventure that lasted all day, starting at three 30 in the morning. And my feet felt great. And I suspect if I had been wearing vibrams, I probably could have done it cuz I’m well-adapted. I’ve been wearing them for years. Uh, but who knows what my feet might have felt like at the end.

Brad (04:48):
And so I’ve, uh, had a recent practice of doing mostly minimalist footwear with my workouts, uh, with my everyday life. And then on occasion, especially when my feet feel beat up, uh, the day after a high jump workout or a sprint workout, I will slip on the pillow shoes and with a big smile and not feel, uh, embarrassed or that I’m departing from my strong commitment to the barefoot and the minimalist shoe lifestyle. And that’s just a great little tidbit that I got from Zach. Much more to come here. He is Zach Bitter old school Zach Bitter.

New Speaker (05:21):
Brad Kearns here in Auburn, California at the finish line near the finish line of the Western States 100 trail running capital. Thanks for joining us in Auburn. It is Zach Bitter, the fat burning beast himself.

Zach (05:35):
<laugh>. Well, thanks for having me, Brad. It’s been a pleasure to follow you guys online and now be on the show.

Brad (05:40):
<laugh> Coming alive from the pages of the book Primal Endurance. And I think the, the intriguing thing, if you read in chapter four about the Faster Study and how you came out burning an incredible percentage of fat, an incredible rate of fat-burning per minute that was beyond what was previously believed to be the human limit. So mm-hmm. <affirmative>, why don’t we start there and tell us about this experience with the Faster Study Sure. And what they were studying and, uh, how it came out.

Zach (06:06):
Yeah. So I think the big goal, the Faster Study was to find out like what is the difference in, uh, your, your energy oxidation rates between carbohydrates and fats in well-trained endurance athletes. So folks who would’ve already maximized the amount of fat metabolizing rate they could achieve through a training stimulus. So now we wanted to add to that what on top of that does diet do? So we had a group of high carbohydrate athletes and a group of high fat athletes as well and paired them up to kind of test these root differences.

New Speaker (06:41):
And I think one, so it’s the high carb diet. So they’ve reported they’re eating high carb for a long time.

Zach (06:42):

New Speaker (06:47):
And then you have these reported high-fat eaters for a long time. So they’re coming into the study totally disparate the way they’re getting to the finish line. Mm-hmm. <affirmative>. But the, they were equal ability. These were all elite leveled people, right?

Zach (06:58):
Yeah, yeah. They, they basically looked at the ultra-running community and tried to find willing participants that had had, you know, won events and, you know, finished high level at these, some of these events and, and

Brad (07:09):
Wants to run for three hours on a treadmill.

Zach (07:11):
Yeah. <laugh>. So yeah. So they basically collected a bunch of data between muscle biopsies, fat biopsies, blood draws, we put on the, the oxygen mask thing, um, during the treadmill session as well as the VO two max test. And, um, and, uh, gathered all the information like rates of fat metabolization during, during these, these, uh, these, this, these events. And, the thing they discovered that I think is most interesting of people is that folks who are eating a high fat diet are able to metabolize much higher rates of fat during, uh, varying intensity levels throughout the course of, uh, of a race or a training training program. So, you know, it’s a really eye-opening piece of information that, that we can use to take to the training table and kind of decide like, what can I do outside of just the act of running or, um, competing in order to improve myself, uh, along the way.

Brad (08:10):
So I guess we’ll get to the study in a sec, but it seems like the overall goal is if you, you can get better and better at burning fat mm-hmm. <affirmative>, you’re gonna need less ingested calories. Mm-hmm. <affirmative>, and it sounds like from stuff we talked about, off camera, um, you’re also noticing improvements in recovery mm-hmm. <affirmative>, um, and, and all these kind of things.

Zach (08:30):
Yeah. Yeah. So I think it is definitely twofold. You’re in the vent and then after the event and in the workout and after the workout and stuff like that. And, um, from what I’ve noticed, uh, you know, from the Faster Study is that, you know, my metabolize my my rate of fat metabolization, which I think peaked at 1.56 grams per minute, you know, which is double average, um, and 50% higher than the, what they used to think was the highest you could possibly get. Um, and I wasn’t even the highest burning one there, there was guys who did higher than that. And just knowing that, like you can manipulate that with your diet certainly puts you in a position to not have to ingest as much during a race. So you’re not diverting as much blood to digestion during an event if you’re not eating as much. And being able to kind of rely on that energy source that you have, uh, relatively unlimited supply of, which is your body fat storage.

Brad (09:20):
So you’re burning a gram and a half of fat per minute. Mm-hmm. <affirmative>, that’s, uh, 13, 14 calories. Yep. That 600 that’s, that’s eight or 900 calories per hour Yeah. Of fat. Mm-hmm. <affirmative>. So basically a 900 calorie per hour effort is, is, uh, that, that’s, that’s pretty aggressive.

Zach (09:41):
Sure. Yeah.

New Speaker (09:41):
So in other words, you don’t need carbohydrate.

Zach (09:44):
Yeah. Pretty much even going part, even going fast. Mm-hmm. <affirmative>, um,

New Speaker (09:47):
you talked on your blog Zach in detail about what you consume during the national 100K championship where you’re running 06:30 miles for hours and hours and hours mm-hmm. <affirmative> and you were throwing down, what would I see in their Mountain Dew and this and that <laugh> and one Oreo cookie. It’s very good. Go read it people, but you’re, you’re topping off the tank when you’re going full gas mm-hmm. <affirmative>, but when you’re in the lab running a comfortable pace, you’re essentially, what we talk about is a fat burning beast. You can go on and on. And you also told me off camera about your Western state’s pacing experience where mm-hmm. <affirmative> how far was that and how, how much did you eat along the, along the way?

Zach (10:23):
Yeah, so I, you know, I, I always run these little tests on myself cause I’m very much, I like, I like to think that I’ve got an open mind and wanna try different things on myself. And I see that I’m an individual, so I need to try it on myself as opposed to say, oh, it worked for them. I must work for me kind of a thing. And you know, when I, when I went to, I paced a friend at Western States for the last 38 miles, I wanted to see like, you know, how good would I feel when I was just taking in water and electrolytes and, um, you know, it was about eight, eight and a half hours out there. And, um, you know, I, I basically took in nothing but water and electrolytes. I, I grabbed a handful of fruit at an aid station one time.

Zach (10:58):
And other than that, it was, uh, you know, it was, it was just, we were just moving through and I didn’t feel really any difference at that low intensity. And, um, so it’s just one of those things where like, you know, you go out and you kind of see like your level of fat adaptation like in real time as opposed to in a lab. Cuz you know, the interesting thing too is like you look at like a pace. So like, at Mad City, my pace held consistent or like a pace held consistent at the Faster Study. You’re not deviating, you’re not like burning any matches, so to speak by doing a fast surge and then backing off or anything like that. Where in a race you might, especially if it’s a hilly course where you’re gonna power up a hill and you might go anaerobic for a bit and then have to try to come back down, you know? So like, um, being able to see that bad adaptation kind of work even in, uh, in, in, in the real live environment is always kind of nice to kind of quantify what, what you’re doing

Brad (11:48):
<laugh>. So if you can go 38 miles over extreme hill canyons, heat with no calories, uh, you’re pretty much fat adapted, would you say?

Zach (11:56):
Yeah. Yeah. <laugh> i’d,

New Speaker (11:58):
that’s a good, good measuring stick maybe. How about sitting at your desk and going without calories for eight and a half hours is still a challenge for many people?

Zach (12:05):
For sure. Yeah. Yeah. People bonk at work every day,

Brad (12:08):
Every day. That’s why they’re vending machines at and napping areas. Yes. Napping pods like at Google.

Zach (12:14):
Right. And I think that’s the most intriguing thing for a lot of people about the lifestyle is that you have this steady supply of energy that you can rely on. Um, and you know, when you’re sitting at a desk or like moving very little, your demands for a high octane source of fuel, like carbohydrates are nonexistent. So like, if you can train your body to be able to tap into that, then you’re doing yourself a lot of favors in terms of not having that two or three o’clock in the afternoon, like, oh, I need another cup of coffee, or I need to take a nap, or something like that. You, you’ve got that steady stream of energy throughout the day.

Brad (12:46):
Um, let’s go back to your beginnings in the ultra scene where you were carbohydrate fueled just like everybody else. Mm-hmm. <affirmative> and going for what was your, your guideline for racing? How many calories were you putting in? What were you using and then what did you notice?

Zach (13:00):
Yeah, I was always aiming for like like three to 400 calories an hour. And I felt like I did better on the high end, so I would always try to hit 400. And, you know, basically that was like, I looked at the literature and it was like, that’s what you can handle anymore than that. Your body can’t process. And like, and I felt any less than that. I’m leaving something on the table, so to speak. So that’s kinda what I aimed at. And I, I guess, I mean, I, I never had a huge issue with digestion on the course, so I just pounded it like, you know, <laugh> it sad already,

Brad (13:26):
What are you consuming like?

Zach (13:28):
Oh, everything, like any sports drink, like soda, things like that gels, all kinds of stuff like that. Like, you know, I’ve since moved to a, what I think is a higher product fuel and x endurance, but at that time it was like, you know, just whatever, whatever was high sugar, like super quick energy source type of thing. You know, and, and what I noticed was I didn’t have trouble. My most people figure out they need to make a change because they find themselves, like at the end of the race puking or going to the bathroom a bunch of times. But I didn’t really have that experience. My experience was more so in day to day life. Like I noticed my recovery was slowing down. I was getting like inflammation and swelling and in my ankles and waking up at night and things like that. So I knew something wasn’t sustainable

Brad (14:15):
And, you know. Oh, so you’re feeling these symptoms mm-hmm. <affirmative> and you’re also hitting it hard and you’re doing crazy ultra schedule, like a lot of the elite do.

Zach (14:23):
Yep. Mm-hmm. <affirmative>.

Brad (14:23):
So when did you think, Hey, maybe I should fool around with my diet?

Zach (14:27):
So it was probably in about, in 2011. I did, uh, three 50 miles and nine weeks and, uh, yeah. And I mean that was on top of like, you know, my, my a hundred plus mile a week training programs and things like that. So I was definitely starting to, to feel it and kind of like, uh, you know, notice some of those, uh, abnormalities I guess like outside of the actual training. And, um, you know, that’s when I decided, you know, do I need to scale back the training in racing to make this sustainable or is there something else I can do? And, you know, I really loved that lifestyle, so I didn’t really wanna scale back much if I didn’t have to. And, um, so I looked at nutrition first and, you know, before that my, my mindset was basically, you know, I’m out there burning two, three times my resting metabolic rate on some of these higher training days.

Zach (15:17):
So I just, you know, supplemented that additional calorie source with high levels of carbohydrate. So what I basically did is I took a large chunk of that carbohydrate fuel source and replaced it with dietary fat. Um, and I right away started to notice a lot of those symptoms going away, like the swelling, the prolonged recovery periods, um, you know, the waking up at night type of thing. Uh, that all kind of went away pretty quick. And then, you know, within about four weeks or so, I started noticing that the switch in energy, the switch in fat as fuels opposed to carbohydrates field during training, um, wasn’t, wasn’t impacting me in a negative way in terms of slowing me down or anything like that. So there’s definitely a transition period, but after about a month or so, a little less than a month, it was pretty much smooth sailing.

Brad (16:03):
Okay. So you battled through that transition period. Are you slowing your training down to make sure that’s, uh, going hand in hand with your transition to a high fat diet?

Zach (16:13):
Yeah, I think a lot of people do better by like not doing much training at all during that phase. Cause you wanna induce as little stress as possible during that phase, that metabolic, which is gonna happen much quicker in a stress free environment. So, um, you know, I, I definitely was at a point where my season was over. I didn’t need to do any speed work or anything like that, you know, I was, uh, you know, doing some easy running and stuff like that. So I was, I was running every day I think, or most days, uh, but at a very casual rate. And you know, what I noticed is in those, uh, those two to four weeks or so when I first started, there were a couple days where I’d feel really, really, really low on energy. You know, I, I’d go up for a run and I’d feel like I was running a lot harder and my pace was actually slower than what I normally would do an easy run at. And you know, after about two to four weeks of that though, like, you know, it wasn’t every day. It was like maybe three days outta the week, I’d have a day like that. And then, but after about two to four weeks it looked over and every day, which is pretty consistent, you know, my easy pace was back to where it normally was. And, you know, the only difference was I would, instead of eating copius muscles carbohydrate, I was supplementing my, my meals and, and snacks with higher fat sources of food.

Brad (17:25):
Okay. So you’re, you’re increasing your fat intake mm-hmm. At the same time you’re trying to cut carbs. Yep. Which I make it a lot easier. You’re not hungry and walking around thinking about a pint of ice cream. Yeah.

Zach (17:37):
Yeah. You know, it’s, when you’re training hard on a high carb diet, I feel like you’re thinking about food and eating all day long. Um, and you’re always kinda hungry and you always get, I remember, um, I’ve talked to other, other guys who’ve made a similar switch to me. It’s like, you, you remember these times where you do a huge training block and you’re full, your stomach is physically full, but you’re still getting hunger pangs, <laugh>, which is just a, to like, I don’t anything in my down my throat. But you get these hunger ps still, so like that, that type of thing is, is gone. Like you, you literally can metabolize body fat or dietary fat, which is much lower in volume too, which I like, cause I’m doing like a two day training block. I don’t wanna have full going that last training. But, you know, if I’m doing high level training, I don’t wanna skipping either. So having that like empty stomach feeling is always nice for, for a workout for sure. Or even just a, an easy long run or something like that.

Brad (18:32):
Okay. So then you get into the race situation mm-hmm. <affirmative>. And as you detail on your blog, um, you’re, you’re fine tuning, especially when you’re going at a fast pace with whatever carb in take you feel, feel you need. Mm-hmm. <affirmative>, how’s that strategy work?

Zach (18:49):
Uh, it worked. It’s basically what I did is, uh, you know, rather than like zoning in on this like 400 calories an hour, like what I used to do, you know, I’ve, I’ve bumped that back way lower to, you know, closer to calories an hour.

Brad (19:05):
This is going full board national championships, running 06:30 miles all day long. So even that is, it’s very few calories mm-hmm. <affirmative>, uh, but you’re probably a guy who needs more calories than anyone behind you in the field because you’re running close, you know, you’re running in the faster pace

Zach (19:19):
Right? Yeah. Yeah. So, you know, it’s one of those things where, like you, I look at the numbers in the lab and I, I feel like I probably need less than I actually do. But then on the other hand, you know, it’s one of those things where I don’t, I’m not doing a whole lot of negatives to go from a 100 to 150. Um, I think I’d be doing some negatives if I went from like a hundred to 400 that just adding way too much extra, like oxidativetive stress from the carbohydrate digestive type, you know, processes. So for me it’s like I always, I err a little bit on the side of caution, um, and take in, and I just try to trickle in carbohydrates really slowly, um, throughout the course of the day at a very low rate. Uh, you know, like at Mad City, like you describing somewhere around calories an what felt right and felt comfortable and even energy levels all day.

Brad (20:09):
So you bring up another point when you said the oxidative stress from consuming the carbohydrate.

Zach (20:14):

Brad (20:15):
So we have these guys, let’s say, that came in the Faster Study mm-hmm. <affirmative>, these are top performing guys. They’re winning races. They’re wearing olives wreathes on their head. They’re, they’re champs <laugh>, but down the line. And Maffetone talks about this too. Mm-hmm. <affirmative>, it’s like, let’s see how long their career will last. Let’s see how often they get injured, sick, burnt out. And so it seems like you can make it work si those carbs if you’re lucky and you don’t have those stomach problems that are leaving you on the sideline mm-hmm. <affirmative>, but like you report you didn’t have the massive digestive difficulties, bbut you notice the swollen ankles and waking up at night and these little things that were indicative of an overly stressful, as you say, unsustainable lifestyle.

Zach (20:54):
Yeah. And you know, that’s, that’s a study that’s less talked about too. They did a study on oxidative stress at Western States in 2012. That was kind of the precursor to the Faster Study. And I think, I think this study actually was what ultimately got like interest in the, the Faster Study getting its funding and getting its ability to be put on and stuff. And what it was, was they were looking at the oxidative stress of ultra runners who were taking a high, high fat diet route or a high carb route. And it was just like the rates of fat oxidation, it was like mind boggling how much of a range it was. Oh really? Some of the high fat athletes came back and like, they didn’t look like there was a whole lot of oxid stress at all really. And then the high carb folks, it looked like there was just some like real horrible things going on. <laugh>.

Brad (21:40):
So they’re actually drawing blood during the race or urine looking at, I’m trying to

Zach (21:43):
Think. They did blood, I can’t remember if they did. I don’t think they did blood during the race. They did like saliva swabs.

Brad (21:48):

Zach (21:49):
So, um, they did some blood draws before and after though too, just to kinda get some baseline markers. Wow. And then, uh, you know, they didn’t interfere too would’ve a draws people would consider a chance of a lifetime run Western States. So they did the, the, um, they did the saliva swabs during, and then I think for like seven days after you kept saliva the swabbing and them freezing them, mailing them in. Uh, and yeah, Dr and Dr were the that up and, you know, it was pretty impressive to see the oxidative stress difference, which, you know, goes right into the recovery phase. Like if you generate tons of ox stress during an event, it’s gonna take you longer to bounce back and be ready for another go. Whereas if you limit that, you know, you feel like you get stronger after it almost, it’s quicker. You know, and you look at like the, the inflammation factor of metabolizing a carbohydrate compared to metabolizing a fat. And that’s hugely different too. So standard reason that for me, my inflammation would go down and my swelling would go down when I’m not causing generating those high inflammatory ox stress type responses from the, of my workouts with carbohydrates.

Brad (23:08):
Well, you have the recovery factor and then you also have the life factor and the aging factor. Yeah. And we detailed this in the book that, um, if you’re training in a chronic pattern and consuming that high carbohydrate carbohydrate dependency eating pattern mm-hmm. <affirmative>, you are literally accelerating the aging process due to your pursuits of endurance sports which are seemingly healthy and you have fit looking people on the starting line, but we now know that they’re not immune from cardiovascular damage, heart disease risk, and also just the breakdown and the burnout from doing something that’s, it’s inherently stressful to go a hundred miles. Yeah. And then you’re, you’re throwing sugar on top of it.

Zach (23:46):
Mm-hmm. <affirmative>. Yeah. Yeah. You’re already doing something that is relatively like non-typical for the human body. Think human’s definitely designed to run and run long distances at slow rates. But hundred miles is probably stretching your luck a little. There’s not a whole lot of like reason to really do a hard hundred miles in any scenario <laugh>. So like yeah. When you’re, when you’re taking something that’s already probably tempting fate a little bit, uh, and then toing it off with something that’s gonna just exasperate the problem, it’s like kinda wanna try to eliminate as of those you can.

Brad (24:20):
And this is great from, Phinney and Volek’s work the art and science of low carbohydrate, uh, living and performance mm-hmm. <affirmative>, um, detailing that the science is showing when you’re in that ketogenic state to make an extreme example of, you know, really restricting the dietary carbs. It has a potent anti-inflammatory effect known to be at the level of the most powerful drugs.

Zach (24:43):
Yeah, yeah. Yeah. It’s, uh, it’s, it’s pretty crazy the difference. And, you know, I’ve had some blood work done when I’m in like a low carb base of training, like a really low like ketosis level and you know, my inflammation markers are incredibly low. Like,

Brad (24:57):
And you’re in the middle of a hundred mile training week, the Whole thing.

Zach (24:58):
Uhhuh mm-hmm. <affirmative>.

Brad (25:00):
That’s crazy.

Zach (25:02):
Some, I’ve had a couple where like, um, I’ve come off like a huge training block where it’s like a, where it would almost simulate like doing a race to some degree. So you would think that’s when those, those inflammatory markers would be the highest and they’re still like really low as long as I’ve those carbs down at, you know, during phase.

Brad (25:19):
So what’s your routine? Like you, are you making a concerted effort to get in that ketogenic state, getting your carbs under 50 or 75 grams a day? Or do you go back and forth?

Brad (25:31):
Yeah, I definitely, um, I definitely range a bit depending on what I’m doing. When I’m in my high intensity, high volume training phases, I’m definitely bringing the carbohydrates back, for no other reason than to seek better performance <laugh>. Um, you know, if I were looking at from a health standpoint, I wouldn’t do that. But then I’m always trying to kind of put a check on that process.

Brad (25:53):
It’s so funny what he just said. Cause you know, the, the opposite has been said so many times. Like, I upped the carbs for no other reason, but for better performance <laugh>. And now this guy is saying he’s lowering the carbs to better performance and he’s winning national championship. So let’s pause for a commercial for Zach Bitter himself and Zach setting us straight and getting rid of those carbs to improve your performance.

Zach (26:17):
Yeah. It’s, it’s,

Brad (26:19):
It’s mind blowing cuz it’s changing every, all the parameters that we’ve previously thought about, which was I guess essentially how good it, how good are you at sparing glycogen or slamming down gels, um, in order to, uh, stay with the pack in front of you.

Zach (26:33):
Yeah. Yeah. And you’re walking that fine line both during the race. Like, am I gonna, am I gonna, my gut gonna fail me or am I gonna have to stop like 20 times?

Brad (26:40):
Is this gonna be my lucky day?

Zach (26:43):
Right? Yeah. So you’re always kind of walking that fine line when you’re depending on that high level of fuel intake during a race and you know, that’s just looking at it in on the surface too. If it gets i it gets hot out, it makes even harder. Like your body gets even worse at being that stomach things. That’s where you see a lot of people’s turns on these hotter races, huh. <affirmative> they go through like the canyons at Western states. And that’s where you can see some people kinda fall apart too because either they continue to try to fuel and they end up puking it back up or they realize they can’t fuel anymore and then they’re trying to slog through the canyons on a body

Brad (27:18):
All of a sudden become fat adapted. Yeah. Yeah. Become found adapted. Mile 45 at Devil’s Thumb, see if I can hang. Right. Good luck.

Zach (27:27):
Mm-hmm. <affirmative>. And that’s where it gets tricky and you know, I always, I guess, you know, one of the biggest questions I always get is like, yeah, well what about the elite 5K 10 K guys and why aren’t they doing this? Or what, where does this fall for them? And you know, I think, you know, they’re definitely gonna have a little different ratios during their intensity phases and things that I do and uh, but they can still have a fat-adapted like mind frame, you know, they can still spend their recovery and spend their easy times or base building phases, in a fat-adapted state to kind put that, that framework in place and then bring the cubs back the same way I do, uh, you know, for these faster events and, and then, you know, still reap the benefits of not accelerating the aging process or, um, you know, the like inflammation factors or the, like, if you’re, if they’re in a scenario to where I was like the swelling and things like that and speed up the recovery. So like, you know, it’s, it’s interesting, it’s, you know, you’re always looking at the lifestyle and like, what do carb where, where is the lo For me it’s always like, what’s the lifestyle and what’s the lowest I can drop my carbs in that lifestyle to still maximize performance, um, without sacrificing, you know, adaptation.

Brad (28:41):
So let’s say you’re doing some of the higher intensity training, you’re pointing for a shorter race or whatever, I don’t know if a shorter race is a marathon for you or something, uh, but I imagine there’s times, how do you do it? Are you doing it before your glycolytic workouts? Are you doing it to recover after mm-hmm. <affirmative> And what kind of carbs are you choosing when you’re upping the carbs from your, your normal baseline?

Zach (29:03):
Yeah, so a lot of times it’s just, uh, you know, I’ll, if I have a big block coming up, um, I’ll really like maybe a day or so or two days before I’ll start kind of like inching it up a little bit, the carbon take a little bit and then I’ll, I’ll try to be pretty strategic about using it during it as well where I’m not like snacking on high levels of carbohydrate when, uh, when I, when they’re gonna be like heavy insulin responses for it. So like kinda that before, during, and after type of mentality once I get into the hard training block is usually a pretty good timeframe to aim for. For me, I aim for mostly like what you consider low glycemic carbohydrate sources, like sweet potatoes, melons, berries, things that aren’t gonna generate a huge like insulin response in my body. So those are kinda the ones I’ll turn of those like water-based fruit sources that are much less super concentrate. Um, and then like some of those slower, slower insulin response type carbohydrates, like maybe raw honey or, you know, like the sweet potato type.

Brad (30:09):
So we had this amazing results from the Faster Study we had, the fat adapted group and the carbohydrate, high carbohydrate eating control group. These guys go home and, uh, start googling stuff. And has there been a change in the, uh, I guess in the trend mm-hmm. <affirmative> in the, in the ultra scene towards that adaptation?

Zach (30:33):
I think there’s definitely been a trend moving, like a higher percentage moving over, at least experimenting with it. It’s always interesting because there’s so much information to be learned. So you, it’s, you run the risk of kinda being like knowing just enough to kinda get, get yourself into trouble <laugh>, um, or you can kinda do it right and kinda see the benefits of it. So you’re walking a fine line there. You know, you definitely get people who try to the, the process and kind of do a not so good job of it and then you end up hearing about them and how it failed for them and stuff. But, uh, Uhhuh,

Brad (31:09):
So what, what would that, what would that look like? Is it, is it someone who’s maybe not doing such a good job cutting carbs and so they’re in this, this wavering zone where they’re not getting enough to refuel like they did in the old days, uh, but still not good enough to be fat adapted?

Zach (31:25):
Yeah, I mean, I see, I see people not let it take hold. Like, uh, is one big thing. They don’t give it that that month or so to kind of like, you know, they don’t, they don’t, they don’t treat it like a detox where, you know, like if you have someone who’s like addicted to like a drug or something like that. You know, they don’t just like decide the next hour and I’m done with this and then it’s all roses after that. There’s a good three, four weeks sometimes where they’re miserable, you know, sometimes they’re checked into a facility so they can handle it and you know, it’s not quite that bad for most for, for a dietary switch, but, uh, there’s definitely like days where you like, I don’t feel as good as I used to. I should, I should strap this.

Zach (31:59):
And I see people giving up after a week or two and it’s like, you gotta give a little more time than that. Um, and then the same hand, you know, you see, you see some of the common pitfalls like, um, they, they lower the carbs and then they also lower sodium and it’s like you gotta be really keep careful eye on those electrolytes when you’re going low carb too. Um, your body just to process more. So you need to take in more. Um, and then, uh, you know, it’s a lifestyle thing too. Like people look at it as like a dietary choice, but there’s so many other things that impact it too. Like, you know, stress, you know, the type the way you’re working out, um, you know, things like things like that can negatively impact the way your body processes the fuels you’re taking in.

Zach (32:41):
So if those things are kinda a mess too, like the diet isn’t gonna necessarily like fix all of that. So if you’re stressing out nonstop and then you go high, high fat, low carb, um, you’re not gonna see a huge like, benefit from it, uh, because you’re just not in a good healthy place to begin with. So you get that from time to time too. And it stands to reason a sport of excess where, you know, <laugh>, you know, it’s like the, the gold standard is to go as far and as long as you can. Like, you know, that you’re gonna have some individuals who are in a chronic state of stress and they need to also kind get that figured out or look at it from a holistic approach along with the dietary thing too, to kinda minimize stress on all areas to really make things work.

Brad (33:23):
I know you’re a popular coach, Zach and can find more information, right? Yeah, yeah. Especially ultra people and ultra people interested in being fat adapted and lowering that oxidative stress of what they’re doing. What are some of the, if you, if you wanted to offer some quick tips here at the end of the podcast to the, the average endurance athlete or ultra athlete that’s looking to make this transition?

Zach (33:45):
Yeah, I think, you know, patience is always key. You know, you have to give it some, give it a little bit of time. Like, you know, for me it was a pretty fast transition, but you know, still two to four weeks where, where things were a little off. So give it that, give it that, that much, that much time and effort if you’re gonna do it. You know, give it, give it a good solid month to see where you’re at first. And you know, don’t, don’t head out trying to like, break any records during that time. Cause goals keep stress low during that phase that’s gonna make that metabolic switch happen a lot quicker. Um, and then just from the, the general training side of things too, like, um, go easy on your easy days and, you know, save, save those hard efforts, uh, for hard days, specific well planned ones that are meant to like move you forward as an athlete, as opposed to just kinda like ending up in that gray area the whole time.

Brad (34:37):
How about sleep? How much do you sleep here? You’re in the middle of your elite career. You’re 30 years old, you’re in your prime.

Zach (34:43):
Yeah, I think if you would average up with the years, probably around eight and a half hours a night or so, you know, there’s, there’s time. There’s nights where I’ll do hard workouts and I’ll sit 10 hours mm-hmm. <affirmative> and you know, there are days where, you know, I’ve got something to get to and I’m a little less than that, but I’m usually, I’m pretty sound at around eight and a half to nine hours usually is a good, good ballpark figure. And, um, I’m a good sleeper and I think that helps a lot, you know, when you can get to bed and stay asleep, you know, it’s a big, uh, big difference then if you’re, you’re kind of burning a cant on both ends, you know, that goes back to the stress standpoint thing too. Like you recover the stress is mitigated to some degree.

Brad (35:20):
So what’s up next for you? What are your big season goals here? 2016? Yeah.

Zach (35:25):
Yeah. I’ve got, um, I’m actually doing the Comrades Ultra Marathon itself, Africa. Nice. Right. You know, that’s the, the next big one on the, on the list. And, um, then I don’t, uh, have another event on the schedule, uh, until late in the season. So I’m looking to kinda of like some things in there plan a couple’s that, uh, I world hundred Ks will probably be for the end of the November, December timeframe, but yep. It’s always fun to, there’s so many good events now, it’s like not too hard to find something <laugh>

Brad (35:56):
The Fat Burning Beast coming live from the pages of Primal Endurance book. Read all about him in there and also check out his blog Zach Thanks for spending the time with us, man. I appreciate it. You’re really on the forefront of this, this trend of fat adaptation. Those numbers from the Faster Study were phenomenal. We’ll put that in the show notes. You can Google that F A S T E R study and see what these elites are doing on the cutting edge of being able to, to burn massive amounts of fat and, and get, get, uh, away from that long standing, decades long carbohydrate dependency that all the, the endurance athletes have been, uh, succumbeded to. Well, thanks for having me on, Brad.

Zach (36:32):
It was a blast.

Brad (36:33):
All right. Have a good day. This is your host, Brad Kearns. Thanks for listening to the Primal Endurance Podcast.

Brad (36:38):
I hope you enjoy this episode and encourage you to check out the Primal Endurance Mastery course at This is the ultimate online educational experience where you can learn from the world’s great coaches and trainers diet, peak performance and recovery experts, as well as lengthy one-on-one interviews from several of the greatest endurance athletes of all time, not published anywhere else. It’s a major educational experience with hundreds of videos, but you can get free access to a mini course with an ebook summary of the Primal Endurance Approach and nine step-by-step videos on how to become a primal endurance athlete. This mini course will help you develop a strong, basic understanding of this all-encompassing approach to endurance training that includes primal aligned eating to escape carbohydrate dependency and enhanced fat metabolism, building an aerobic phase with comfortably paced workouts, strategically introducing high intensity strength and sprint workouts, emphasizing rest, recovery, and annual periodization. And finally, cultivating an intuitive approach to training. Instead of the usual robotic approach of fixed weekly workout schedules, just head over to Primal and learn all about the course and how we can help you go faster and preserve your health while you’re at it.

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