Low-Carb Athletes: World-Record Ultra-Runner Zach Bitter

From 2013: The post in which I first heard of Zach Bitter and his accomplishments and approach. I just finished an interview with him, which is a follow-up to this post, and will be released in 2024.

Dec 17, 2013

Hold your hats: World Record: ran 101.66 miles in 12 hours; American record: 100 miles in 11:47:13. The world record he broke was Greek God (that's not ironic, it's literal) Yiannis Kourus's* record.

That's a 7:04 pace (minutes per mile), for more than 100 miles. Wow.

And, just to make it extra cool, he did it wearing minimalist shoes and eating a low-carb paleoish diet.

Nutrition

He has a recent post on his blog describing his diet:

"My personalized OFM [Optimized Fat Metabolism] approach can be characterized as macronutrient cycling. While my protein intake fluctuates little (typically 100 to 150 grams per day), my carbohydrate intake can be anywhere from 5 percent of my total calories to 50 percent, depending on where I am in my training cycle. When I am in full recovery mode after a race, I drop my carbohydrate intake as low as possible. On the other hand, my carbohydrate intake is around 20-30 percent of my total calories when my training is ramping up in volume and intensity, and in the final 36 hours before a race I allow it to climb to 50 percent at most.
"All carbohydrates are not created equal. I don’t eat grains; I think the way grains have been engineered in the past several decades has made them hard on digestion and the likely cause of many of our broken guts. I also stay away from lactose, simply because my body doesn't seem to digest it very well. Commercial dairy producers have removed the enzymes in dairy that help our bodies break down lactose. Since our bodies cannot produce these enzymes on their own, this results in bloating and indigestion. I will drink raw milk if it's available, but I don't go out of my way to get it.
"My primary source of carbohydrates is vegetables. I usually opt for non-starchy vegetables, but when I am looking to raise my carbohydrate intake I do eat carbohydrates from starchy sources, such as potatoes, sweet potatoes, or rice. Another source of carbohydrates I use is fruit. I try to focus on melons and berries, as they are less apt to spike insulin, but I do eat things like apples, pears, and peaches from time to time.
[Tuck: I will note that "non-starchy vegetables" are metabolized into fats, basically: from a metabolic perspective they're not a carbohydrate. They will not enter the blood as glucose. P.S. See the first comment for a clarification from Zach.]
"After protein and carbohydrates, the rest of my calories, of course, come from fat—often more than half my daily calories. Just as with protein and carbohydrates, I pay close attention to the types of fats I consume. I take in approximately 50 percent of my fat as saturated fat.... The remaining 50 percent I try to make mostly monounsaturated fat, with very little coming from polyunsaturated fat sources. The polyunsaturated fat sources are a recipe for inflammation, especially when a diet is low in omega-3 fatty acids, so I avoid them for the exception of the occasional snack of mixed nuts or nut butters. A few go-to fat sources I enjoy include: coconut milk, coconut oil, butter, animal fat, avocado, extra virgin olive oil, and cheeses (full fat, to avoid lactose).
"One of my favorite dishes to eat is a mix of vegetables (mostly greens) with fresh calf liver, bacon, and sour cream..."

He never uses the phrase Paleo, but that's what it is. Robb Wolf or Mark Sisson would approve of his approach of cycling carbs up and down as required by training and racing: what's really interesting in the focus on lowering carbs for recovery.

So by that standard, he's not strictly a low-carb athlete, as he's approaching this primarily from the perspective of maximizing fat metabolism, but I think that that's the right approach to take: it's not about which macronutrients you eat: the goal is maximizing health and performance. Minimizing carbs is a key part of that, but eliminating them isn't necessary for a healthy person. From an interview with Case Performance:

"...I would describe my intake as low carb, high fat, and moderate protein...."
"In terms of converting from a high carb to high fat based diet, there was probably a 2-3 week adjustment time period and I did feel "flat" during a couple of the workouts. However, it was well worth it. Since switching, I have found that a diet based on fats promotes quicker recovery, better sleep, and a more consistent level of energy throughout the day. My race times have consistently better since switching over as well."

He also discusses his approach to carb-loading:

"Basically, I begin to add more carbs 2-3 days out from the race. I focus on carb sources that are gluten free. Sources include: starches (potatoes/sweet potatoes), fruits, and raw honey. I decide how much carb based on the intensity of the race. If I would be heading into a 100 mile race I would add much less carb, as my body would be more apt to remain in a fat metabolic state."

And, in line with Wolverine's approach to hydration:

"If I am going out for a long steady paced run. I will do very little pre/during workout fueling. I will take in some amino acids in order to stave off any muscle catabolism, and water with some unrefined sea salt."

Shoes

On the shoe front, he appears to have been wearing the Skora Base (on sale now!). Skora was a company that was started early in the minimalist shoe wave after Born to Run was published, and then went radio silent for a long time as they tried to get production started. Many of us figured that they wouldn't make it, and here they are, owning a world record. Congratulations to Skora! From their website:

"BASE is the ultimate, multi-purpose running shoe. Equally at home on the road, in the gym or racing a triathlon. BASE offers a stretch-mesh sockfit with an innovative adjustable X-strap system, elastic heel strap, reflective details and stitch-down construction with an Ortholite insole. Lightweight, quick-fit, and unique in design, BASE offers a lightweight cushioned ride with 13mm stack height (9mm without insole).
"BASE is built on the R01 platform composed developed to offer a unique anatomical fit that closely matches the foot’s shape. The R01 platform also features a zero-drop outsole/midsole with just enough cushioning and a curved section profile in both the forefoot and heel. This allows for optimal natural movement and performance.

While I've not tried Skora's products, they're a real minimalist shoe. A little beefier than a Vapor Glove (nearly twice the VG's feathery weight), but all the right features. Birthday Shoes did a nice review when they came out. Zach elaborates on how he adopted minimalist shoes:

"The practice of wearing shoes—with all their padding and support—regularly has weakened our foot muscles. Weak muscles need to be exercised with gradual incremental increases in order to avoid injury. It's the same reason why you don’t go from running 10 miles a week to running 100 miles a week without a build-up. Likewise, to effectively run with a minimalist shoe, one must slowly transition. If you're interested in learning about my transition to minimal footwear, keep on reading; I recently completed a 50-mile trail ultra in a pair of minimalist shoes."

And now he has a world record. Well done. Thanks to Sean for bringing this to my attention!

* If you don't know who Yiannis Kourus is, start here, but to sum he's the greatest distance runner in history, with no close second.

P.S.

That's a 7:04 pace with bathroom breaks! Here's Zach's race report at iRunFar, and a couple of notes following up on what's above:

He was indeed wearing the Skora Base shoe.
His pre-race nutrition was pretty low-carb...
During the run he ate banana chips, potato chips, Mountain Dew, Gatorade, and had some M&M’s when he had a mini-bonk at mile 95.
He wore an iPod shuffle. Can you blame him? 100+ miles on a track? I'm amazed he could stay awake...

Read the whole thing, and congratulations, again.

P.P.S.

I listened to the Ultrarunner Podcast interview with Zach. Best line (discussing Kouros and doing a 72-hour run in the near future):

"I think I'll stick to the short stuff..."

LOL. He's an interesting one, Zach is. He's minimalist and paleo solely for performance reasons, not because he thinks they're intrinsically better for health. He drinks beer, for instance, so he's not totally grain-free.

One other funny comment: one of the interviewers asked him about Achilles tendonosis, and Zach observed that he used to get it, but not since he went minimal. He also said that he'd use up to a 10-mm drop shoe, but all the shoes that he mentioned using (Skora and Altra) are zero-drop.

Additionally, as above, he made the point that (in essense) adapting to minimalist shoes is building up the muscles in your feet and lower leg. He noted that he doesn't (obviously) have any problems with strength in those muscles now.

I think this is a great point: a lot of people think that minimalist shoes "don't work" for them, when in fact their feet are still just really weak.
Oh, and thanks, Mark.

Comments

Transitioning from Blogger to Substack doesn’t bring comments (since their automatic tool doesn’t work). So I’ve included these, since it’s not usual to get a comment from the person you are writing about!

Zach Bitter December 26, 2013 at 11:24 AM
You did your homework :) I can't say you misquoted or misinterpreted anything on this overview. I would like to clarify that when I discuss macronutrient percentages I am speaking in terms of everything. I don't go back and subtract non-starchy carbs/fiber carbs from the total. So when I say "30%" carb intake that includes all the non-starchy fiber in my diet. I know a lot of people will subtract that when they count their carbs.

Thanks for the well written overview!!!

Tucker Goodrich December 27, 2013 at 6:17 AM
Thanks, Zach.

Zach Bitter January 5, 2014 at 10:50 AM
Also, the beer thing. I can count on one hand the number of days in a year I consume alcohol, so that makes up a very small portion of my intake throughout the year. Ultrarunner podcast does a thing where they ask interviewees about their favorite beer. I didn't want to cramp their style :)

Unknown January 1, 2014 at 1:54 PM
Hi Tuck and Zach,
Very impressive record! Good to the low carb being embraced by more and more.
Out of sheer curiosity, how much calories/grams of fat do you consume on average on a daily basis?
Best,
Thomas Hemming

Zach Bitter January 5, 2014 at 10:47 AM
Like Tucker mentioned, it really varies at where my training cycle is at. When I am recovering my carb intake gets as low as 5%, protein about 20%; leaving fat at around 70-75%. I am also eating less in recovery, because I am not training as hard or at all. When I hit peak training (up to 150mpw, and at times up near 190) I will up my carb intake to between 20-30% (this is without subtracting fiber, and non starchy carb sources). In training weeks like this I am probably consuming between 4-5000 cal. (rough estimate). This would mean roughly 50-60% of my intake is fat (2000-3000 cal).