Zach Bitter: Ultramarathon Running | Lex Fridman Podcast #205

Zach emphasizes the importance of completing the first 100-miler, even through a 'death march,' to build a template for future races. He views quitting in an event as scrapping months of preparation, making it a stronger disincentive. While advising against quitting mid-activity, he also notes the importance of assessing if an activity is truly meaningful, and acknowledges a point of diminishing returns where 'quitting' or resting is beneficial for long-term health and training.

Zach found it crucial to step away from repetitive goals occasionally. For example, after extended focusing on flat 100-milers, he trained for the technical San Diego 100 trail race. This change in environment and skill set "reset" his mental energy, making him more excited and motivated to return to flat-course training with renewed vigor.

Currently, the three biggest ultra-marathons are the Western States 100 (most competitive 100-miler on trails in the US), Ultra-Trail du Mont-Blanc (most competitive 100-miler on the planet, attracting international talent), and the Comrades Marathon (technically 56 miles, most competitive road ultra-marathon).

Beyond physical fitness, Zach finds enjoyment in 'runner's high' and the feeling of being able to 'take on the world' after a run. Long-term, he values the process of incremental improvement, akin to getting a 'gold star' for progress, and sees race day as an artistic expression of training.

Popularized by Dr. Phil Maffetone's Maximum Aerobic Function (MAF) training, the '180 minus age' formula provides a target heart rate for building an aerobic foundation. Training at this low intensity promotes fat metabolism, minimizes injury risk, and allows for consistent high-volume training. Actual heart rate and perceived effort (e.g., ability to converse) can help calibrate this number.

Most plans prioritize building a strong aerobic foundation (base runs at MAF heart rate) for 8-12 weeks. Once the base is established, more specific workouts like short and long intervals or tempo runs are introduced. The order of these specific workouts depends on the target race distance, moving from least specific to most specific closer to race day.

Zach, who has followed a low-carb diet for 10 years and adopted a high-meat consumption during his best racing season, believes it's highly individual. While many elite athletes use carbs, some individuals (like Lex Fridman and Zach Bitter) perform better on low-carb/carnivore diets psychologically and physically, especially for ultras where fat metabolism is key. This approach may not yield Olympic-level performance but can be sustainable and effective for long-term active lifestyles.

Zach focuses on burning high levels of fat. The night before, he might have some carbohydrates, but breakfasts before a 100-miler are low-carb, high-energy, and low-volume (e.g., S Fuels life bar) to encourage fat burning. About 45 minutes into the race, he introduces small amounts of carbohydrates (15-40 grams per hour) to defend muscle glycogen, noting that 40 grams is his digestive limit. This differs from standard recommendations of 50-100 grams for carb-adapted athletes.

Zach plans to run across America, from San Francisco to New York, living out of an RV and running ~70-80 miles daily for about 42 days (to challenge the record). The biggest challenges include managing day-to-day logistics, consuming 10,000-15,000 calories daily without digestion issues, minimizing injury risk from repetitive impact, and adapting mentally to continuous effort.

Modern shoe technology (like Nike's 'peabod' foam with carbon plates) has significantly impacted road racing, offering a 2-8% performance advantage, leading to numerous broken records from 5K to marathon distances. Its impact on ultra-running is less, as most ultras are on trails where this tech is less effective. The introduction of these shoes also created a fairness debate among sponsored athletes during its prototype phase.

Olympic sports often involve extreme optimization, with athletes dedicating their lives to a single race over years, often with specific physiological and nutritional requirements. 'Pure challenge' events, like Burt Kreischer's 2000-mile goal or Zach's transcontinental run, can be undertaken with less optimization and more of a 'just do it' mindset, revealing different aspects of human spirit and resilience without solely focusing on peak performance metrics or intricate scientific planning.

Effective training and diet are highly individual. What works for one elite athlete (e.g., high-carb) may not work for another. Flexibility to adjust training intensity based on how one feels, rather than strict adherence to metrics, is important for enjoyment and sustainability. Similarly, choosing a diet that makes one feel good, even if non-traditional (like carnivore), is crucial, as is balancing optimization with embracing life's 'chaos' (e.g., alcohol) for overall well-being.