Advertise on podcast: Human Performance Outliers Podcast with Zach Bitter

Kim Gottwald is a German ultra runner and content creator who went from law student to backyard-ultra standout by documenting extreme projects in public, including a co-win at Go One More in Texas, and a 449 km Last Soul Ultra victory at home. He co-founded the running brand Rappid, became BPN's first German athlete, and now hosts Germany's Last Soul Ultra. He has big plans for expanding Last Soul Ultra into multiple locations, including the US. Kim: kimgottwald.info | IG: @kim.gottwald | YT: @Kim.gottwald Episode Sponsors: LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (25% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

Phil Gore holds the World Best mark for the Backyard format, completing 119 "yards" for a total of 495.83miles. He recently completed a personal project, called Project 168, where he aimed to see if he would be able to last 168 yards (700 miles). He ended up tapping out at 152 yards (633.75 miles). We discussed this project, what the limiters were, how they have created a longer recovery, and what direction the Backyard Ultra World is going, and how his event raised nearly $300,000 for Telethon, a Western Australian appeal that supports sick, vulnerable, and disadvantaged kids and their families. You can contribute here: philgore.com.au Phil: philgore.com.au | IG: @phil.gore.ultrarunner Episode Sponsors: LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

Brian Reynolds is a Brooks-sponsored double below-knee amputee runner who, in 2026, became the first athlete in that category to finish the Leadville Trail 100 — on his fourth try, in 28 hours 55 minutes. He lost both legs at age four to meningococcemia, a rare bacterial infection with grim survival odds. For years he hid the amputation and stayed off the trails. A Grand Canyon hike cracked that open. He went from powerlifting to a 2:58 marathon, multiple classification records from 5K to the marathon, and Team USA para-athletics. Brian: IG: @brianreynoldsrunner Episode Sponsors: LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

Phil Gore holds the World Best Backyard record with 119 yards (495.87 miles). In an effort to see what he could actually do, he set up a project targeting yards/hours. Meg Eckert may be the most underrated ultramarathon athlete in the game right now. She is currently on pace to break her own women's 6-day World Record, and also the outright American Record. Finally, I touch on some thoughts around the UTMB events.  Episode Sponsors: LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

Thomas Nobbs is a professional marathon athlete with a 2:09 PR, and endurance coach. His progression to 2:09 speaks for itself, and his public strava profile shows how he has balanced lots of low intensity running and key quality sessions. Thomas is currently training for the Chicago Marathon, where he plans to once again improve his marathon PR.  Thomas: teamrunrun.com/coach/tom-nobbs | IG: @nobbs.not.knobs | Strava: Thomas Nobbs Episode Sponsors: LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

Dr. Trent Stellingwerff joined the show to discuss the topic of relative energy deficiency syndrome (REDs) in endurance athletes, and body competition management. Trent includes working with the Women's Health, Sport & Performance Institute (WHSP) in Boston Trent is the Chief Performance Officer (CPO) at the Canadian Sports Institute. Trent has developed many national and international collaborations in various applied research projects in the fields of nutrition and physiology, and been a part of 8 IOC position statements. Trent joined the show to discuss the topic of relative energy deficiency syndrome in endurance athletes, and body competition management in athletics. Trent: whspinstitute.org & csipacific.ca/team-members/trent-stellingwerff | X: @TStellingwerff   Sponsors: LMNT: https://drinkLMNT.com/HPO (free sample pack with purchase) deltaG: https://deltagketones.com Code: BITTER20 (20% Off) Support HPO:  Website: https://zachbitter.com/hpo  Patreon: https://patreon.com/HPOpodcast  Coaching: https://zachbitter.com/coaching  Zach's Newsletter: https://substack.com/@zachbitter

Mark Dowdle arrives 15 minutes before the start of Last Soul Ultra, but still wins with nearly 400 miles. Should we have more unsupported ultra running events? Badwater 135 lack of streaming and interesting shoe policy. Jeff Garmire joins me to discuss and share his upcoming documentary. Jeff Garmire: freeoutside.com | IG: @thefreeoutside | YT: @Freeoutside Episode Sponsors: LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Kila Insoles: kilarun.com Code: BITTER ($50 Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

Matt Fox joined me to chat about his interest in the marathon after coming from a National class middle distance background, his trajectory with content creation, the Chinese running shoe market, and his power weight ratio journey.  Matt Fox: sweatelite.co | IG: @mattinglisfox Episode Sponsors: LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Kila Insoles: kilarun.com Code: BITTER ($50 Off) Episode summary: Zach Bitter interviews Matt Fox (Sweat Elite) Matt's background: Former Australian middle-distance runner who twice finished 5th at Olympic/World trials (consistent 1:48 800m). Felt he "failed" after never making a national team, which later fueled his curiosity about how better runners train. How Sweat Elite started: After a failed Strava-like app, Matt launched a site interviewing pros. He later began filming elite workouts (inspired by old FloTrack videos), but it lost money due to last-minute travel costs and limited YouTube revenue. He recouped losses by documenting his own marathon builds. Content landscape: Athletes now prefer posting their own journeys, making third-party workout videos harder. Influencers-as-coaches is a growing issue; both agree formal qualifications aren't required (many great coaches never had them), but buyers should do due diligence. Bad influencer coaches can still introduce people to the sport who later seek better help. Creators they follow: Truett Haynes (humor + ambitious Olympic Trials goal despite current times being far off; recently hired Rory Linkletter). Also Eric Floberg (cinematography) and Rory Linkletter (authenticity, Canadian marathon record pursuit). Weight/body composition debate: Matt accidentally got very lean (70 kg) for a 2:20 marathon, then gained 3–4 kg and plateaued at 2:23–2:24. After noticing he was much larger than the Japanese runners he raced with, he used carb-cycling (high carbs around key sessions, deficit on easy days) to drop back to ~69 kg and ran 2:18–2:19. He has since lost another ~12 kg. He stresses this is highly individual and risky. Personality matters: people with OCD/obsessive tendencies are more likely to develop RED-S or eating disorders. He now studies nutrition to give safer guidance. Examples cited: Josh Kerr's long-term leaning-out, George Cush dropping weight before winning Comrades, Ryan Hall hitting a point where further loss hurt performance. Both emphasize timing (fuel hard sessions, restrict on recovery days), not living in a perpetual deficit, and resetting after races. Chinese super shoes: Matt recently lab-tested 12 models from Anta, Li-Ning, 361°, Xtep, Dynafish, etc. Many perform comparably to Western shoes at half the price and often last longer. Notable mentions: Li-Ning Dragon Flight (79 g, technically illegal but extremely fast; a legal version is coming), Anta C10 (very similar to Puma Fast-R), Dynafish trainer (versatile, durable, sub-200 g). Barriers in the U.S.: high tariffs, limited specialty-store distribution, and brands currently focused on the Chinese market. Anta and Li-Ning are expanding globally. Matt's current status: Recovering from injury, posting daily on Instagram/Strava as Matt Fox. Targeting a 2:17 or faster at the Melbourne Marathon in two months. Timestamps: 0:00:02 — Intro and welcome to the episode 0:00:45 — Matt shares his background and connection to the podcast 0:01:42 — Matt's unusual running journey and early Sweat Elite work 0:04:33 — Matt's competitive middle-distance background and Olympic trials attempts 0:05:50 — Stepping away from elite running and building Sweat Elite 0:07:19 — From a failed app to interviewing pro runners 0:09:06 — Building content, monetization challenges, and workout videos 0:13:10 — Athletes making their own content and the creator/brand shift 0:14:36 — Should influencers need qualifications to coach? 0:21:08 — Coaching credentials and the role of experience 0:22:34 — Content creators Matt is excited about 0:25:46 — Truett Haynes, Rory Linkletter, and the entertainment factor 0:31:34 — Transition to weight, performance, and body composition 0:33:19 — Matt's marathon progression and how weight loss affected performance 0:40:27 — The nuance of weight loss, RED-S, and individual differences 0:48:32 — Why the conversation is different for different runners 0:50:22 — Timing carbohydrates and avoiding energy deficiency 0:52:19 — George Kusche at Comrades 0:57:30 — Josh Kerr seemingly fully optimized 01:03:12 — Chinese running shoes and why they matter 01:06:12 — Jack Crago and testing Chinese shoe models 01:08:25 — Distribution, tariffs, and market access in the U.S. 01:13:02 — Shoe durability and foam life 01:15:28 — Lightest legal shoes and new tech from Chinese brands 01:17:42 — Anta, Puma, and the global shoe market 01:19:04 — Puma concept shoes and performance development 01:20:49 — Why Chinese brands are expanding more slowly in the West 01:22:12 — Matt's trip to China and how he got deeper into shoe tech 01:23:54 — Dynafish and ultra-light trainers 01:26:12 — Wrap-up, where to find Matt, and final thoughts

I reached the end of my journey with the blood clot I discovered at the end of June. I learned a lot through the process, along with information about my personal risk for blood clotting. I unpack all of that and share my return to training.  Episode Sponsors: LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Kila Insoles: kilarun.com Code: BITTER ($50 Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

Vic Johnson shares the practical limits of high-carb strategies, discusses how carbohydrate needs can exceed what the gut can absorb, especially under heat and high intensity. Vic shares typical successful ranges, why hotter races and faster pacing worsen digestion, and emphasizes consistent intake over large boluses that can trigger GI issues. They discuss individualizing targets for mid-pack runners, finding a personal carb "cap" in training then scaling back for race day, sex differences (body size, culture, psychology), links between GI issues and disordered eating, the role of day-to-day carb intake in building intestinal transporters, and practical choices between drink mix vs gels. Vic Johnson: mountainsportsnutrition.com | IG: @mountain.sports.dietitian Episode Sponsors: LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) True Nutrition: truenutrition.com/hpo Code: HPO (20% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

Kilian Korth joined the show to have a discussion around ultrarunning's growing professionalization without sophisticated regulated drug testing, the limits and trade-offs of WADA/USADA-style regimes, and why "doping" as a blanket term obscures intent and severity. We unpack gray areas such as THC thresholds, TUE complexity for common medications, transparency vs backlash, influencer incentives, and the future pressure regenerative medicine and technology (e.g., super shoes) may place on sport rules. Kilian: IG: @runtoughmindset | Substack: https://substack.com/@runtoughmindset Sponsors: LMNT: https://drinkLMNT.com/HPO (free sample pack with purchase) deltaG: https://deltagketones.com Code: BITTER20 (20% Off) True Nutrition: https://truenutrition.com/hpo Code: HPO (20% Off) Episode Summary & Notes: Zach Bitter & Kilian Korth on PEDs, incentives, and doping in ultrarunning Context & framing Conversation is the third appearance by Kilian on Zach's podcast; shifts from traditional training/racing episodes toward current events in running. Sparked by recent doping-related controversies (Cam Hanes / Sage Canaday online conflict, Mike McKnight's discussion of BPC-157 use on Hanes' podcast). Both emphasize moving beyond narrow focus on specific peptides/cases to broader structural issues. Activism, incentives & tribalism Skepticism of modern activism: good causes often get distorted by perverse incentives (attention, platform growth, organizational self-preservation/mission creep). Online environments (especially short-form social media) reward polarization over curiosity or truth-seeking. Parallel drawn to low-carb diet advocacy: movement shifted from exploration of pros/cons toward dietary supremacy and identity attachment. Both hosts value changing one's mind with new evidence and prefer evolving conversations over tribal "debates" aimed at winning. Core problem in ultrarunning Rapid professionalization and financial incentives exist, but sophisticated testing (especially out-of-competition) is essentially absent. Honor-code system + high rewards creates conditions in which some athletes near the top are likely to use PEDs. Contrast with Olympic sports (e.g., swimming) where positives occur even with lower financial stakes. "Doping" is an unhelpful blanket term that equates intentional, high-impact cheating (e.g., EPO) with gray-area or accidental cases. BPC-157 and gray areas BPC-157 is an experimental peptide with very limited human data (one small study of 12 people among 36 total studies reviewed). Anecdotally has been used for tendon/muscle healing; on the WADA banned list at all times (no TUE pathway currently). Gray areas exist in WADA criteria themselves (performance enhancement potential, health risk, "spirit of the sport"). THC example: banned in-competition with a relatively high threshold; removed alcohol from the list is an example of changes over time. Distinction between letter of the rules vs. moral/cosmic fairness; between intentional advantage-seeking and medical/recovery use. Testing realities & practical challenges Full USADA/WADA-style regimes require whereabouts reporting, out-of-competition testing, and significant lifestyle constraints (conflicts with the free-spirited, remote nature of trail/ultrarunning). Even gold-standard systems have loopholes (missed whereabouts, remote camps, short-acting substances timed around sleep windows). Half-measures are expensive, burdensome, and unlikely to deter determined cheaters. Middle-of-pack and age-group athletes face different calculus; many use legitimate medications (inhalers, etc.) that may or may not require TUEs depending on type and dose/threshold. Possible paths forward discussed Transparency and honesty should be encouraged rather than punished (both hosts respect that Hanes and McKnight disclosed BPC-157 use). Practical ideas: Optional "non-competitive / open" checkbox so athletes using regulated substances can still participate without affecting results/records. Tested vs. non-tested divisions (bodybuilding-style model). More education needed around legitimate medical use (TUEs, Global DRO checks). Focus should prioritize the small professional/elite tier where financial and competitive incentives are highest over age-group minutiae. Future regenerative medicine and longevity interventions will force further adaptation; sport has already accepted large performance gains from technology (super shoes) more readily than internal/medical ones. Influencers & broader culture Influencer economy adds complexity: financial incentives to promote products or share experimental practices; difference between sharing personal experience vs. recommending use. Transparency with clear caveats is preferred; pure anecdote-driven advice remains problematic. Societal issues (tribalism, algorithmic incentives, low scientific literacy) make clean solutions difficult inside a small niche like ultrarunning. Closing notes Both stress nuance over black-and-white absolutism Conversation aims to push the sport toward honest discussion of incentive structures rather than endless case-by-case outrage. Kilian's Substack article ("The Run Tough Mindset") and upcoming documentary Forged in Failure are referenced as related material.

Josh Kerr shattered the mile World Record, running 3:42.66. Everett Smulders has run 3:58 in the mile, and follows the sport closely, so he joined me to discuss everything surrounding this historic day. We dive into what made this such a mainstream attention grabber, what made it stand out from similar accomplishments, and a variety of other topics.  Everett: wesflytrained.club/apply? I IG: @coachsmulders Episode Sponsors: True Nutrition: truenutrition.com/hpo Code: HPO (20% Off) ProBio: probionutrition.com/endurance Code: Endurance (20% Off) LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

There was recently some controversy at the Biotropica Backyard Ultra where both the men's and women's world bests were broken. After the event concluded, it was revealed that some violations occurred, causing all results from the event to be disqualified, including the top performances. Mark Dowdle joined me to discuss what happened, along with other related topics around rules in the sport of ultra marathon.  Mark Dowdle: IG @mark.dowdle | YT @mark.dowdle Episode Sponsors: ProBio: probionutrition.com/endurance Code: Endurance (20% Off) LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

Lotti Brinks is a rising star in the sport of trail ultramarathon. She has improved year over year, which recently resulted in finishing 5th at the 2026 WSER 100. She joins the show to discuss history with the sport of running, introduction to the sport of ultramarathon, becoming a professional athlete with Hoka, the growing trend of race day optimization with team training camps, and how she has shaped her mindset to stay balanced in life outside of being a professional runner. Lotti Brinks: @lotti_brinks | https://www.strava.com/pros/25210246 Episode Sponsors: ProBio: probionutrition.com/endurance Code: Endurance (20% Off) LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) True Nutrition: truenutrition.com/hpo Code: HPO (20% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter

The Comrades Marathon is one of the most competitive ultramarathons on the planet. The 99th running of the historic point to point course recently saw both the men's and women's course records go down. George Kusche was the men's and overall winner with a time of 5 hours 15 minutes 56 seconds over the 85.77 km net uphill course.  George Kusche: @kuschegeorge Episode Sponsors: ProBio: probionutrition.com/endurance Code: Endurance (20% Off) LMNT: drinkLMNT.com/HPO (free sample pack with purchase) deltaG: deltagketones.com Code: BITTER20 (20% Off) Podcast Details: Support HPO: zachbitter.com/hposponsors HPO Website: zachbitter.com/hpo  Zach's Coaching: zachbitter.com/coaching Zach's Journal: substack.com/@zachbitter Find Zach: zachbitter.com | IG: @zachbitter | X: @zbitter | FB: Zach Bitter | Strava: Zach Bitter