Vegans vs Meat Eaters: Who Will Live Longer & Why You Should Care! | Jonathan Reisman Pt 1
Dr. Jonathan Reisman discusses human anatomy, nutrition, and longevity with host Tom Bilyeu, arguing that humans are omnivores adapted to variable diets and that optimal nutrition depends on individual lifestyle and activity levels rather than adherence to pure vegan or carnivore approaches. He emphasizes understanding bodily systems and the origin of food as key to health optimization.
Summary
In this episode, Tom Bilyeu interviews Dr. Jonathan Reisman, an anatomist, about the intersection of human anatomy and nutrition. The conversation begins with a discussion of ancestral eating patterns, using the example of Comanches rapidly consuming organ meat from freshly killed buffalo. Reisman explains that human gastrointestinal tracts are highly adaptable, evidenced by examples like the panda bear's evolutionary shift from carnivore to herbivore. He argues that humans are omnivores without a GI tract resembling either pure carnivores or herbivores, suggesting optimal diet varies by context.
Bilyeu proposes a hypothesis about vegan diets and longevity, suggesting that vegan diets may provide hormetic stress that activates longevity pathways by avoiding constant mTOR activation associated with high meat consumption. Reisman agrees this makes theoretical sense but emphasizes the science remains murky. He stresses that modern lifestyles differ drastically from ancestral ones—we have abundant global food access and minimal physical activity requirements—which should inform dietary choices differently than evolutionary patterns would suggest.
Regarding medical expertise in nutrition, Reisman reveals that medical schools provide minimal nutrition education (his had one recently-added course), making doctors skeptical authorities on the topic. He notes that nutrition science is methodologically difficult due to numerous uncontrolled variables, leading to frequent reversals in medical recommendations (exemplified by eggs). He distinguishes between medicine's focus on disease prevention and the optimization of human performance, noting that blood and urine tests can only confirm the absence of deficiency, not optimal health.
The discussion shifts to Reisman's personal philosophy of understanding where food originates. He describes teaching his children about the circle of life and food chains, including his practice of dissecting roadkill to understand animal anatomy. He explains his fascination with ancestral skills like hide tanning using animal brains, seeing beauty in understanding complete material transformation and human history. He clarifies that this interest stems from intellectual curiosity rather than squeamishness, noting that even highly squeamish medical students quickly acclimate to cadaver dissection.
On the question of amino acid completeness in plant-based diets, Reisman acknowledges that vegan diets require careful planning to avoid deficiencies (particularly B12 and complete proteins) but are achievable with modern supplements and nutritional knowledge. He emphasizes that in modern, low-activity lifestyles with global food access, people can maintain health on various dietary approaches, unlike ancestral humans who had fewer choices.
The conversation explores why animals target specific organs (liver, bone marrow, fat) when hunting, with Reisman suggesting nutritional density drives these choices. He discusses how instinct operates—whether learned from parents or genetic—remains unclear but suggests evolutionary selection favored efficient hunting patterns.
On the medical applications of AI, Reisman sees potential in large-scale nutritional epidemiology studies, disease diagnosis (particularly for rare conditions and cancer screening through biomarker analysis in exhaled breath or stool), and differential diagnosis support. He notes that Google and ChatGPT-4 already excel at identifying rare diseases from symptom constellations. However, he emphasizes that diagnosis remains as much art as science, requiring subtle observational skills refined through experience—such as recognizing respiratory distress from watching breathing patterns rather than relying solely on instruments.
Reisman describes emergency medicine diagnosis methodology, starting with skin color and overall "gestalt" to assess severity, then systematically gathering clues through examination and testing. He provides examples of rapid diagnosis (perforated ulcer presenting with green skin, pneumothorax with gray skin and absent breath sounds) and explains procedures like chest tube insertion using water seals similar to fermentation locks.
Finally, Reisman describes his approach to patient care as consultative rather than prescriptive. For conditions with multiple acceptable treatment paths (like early skin infections), he presents options with risks and benefits, allowing patients to decide based on personal values and risk tolerance. He argues that neither aggressive early intervention nor conservative watchful waiting is objectively "wrong"—the right choice depends on individual preferences and circumstances.
About this episode
<p>When it comes to figuring out what an optimal diet and lifestyle is for you, it becomes evident that our approach to what is optimal for each of us is radically different, which means we have to let go of the notion that any specific diet is better than the other.</p><p>Dr. Jonathan Reisman is not your average ER doctor. He has one of the most unique perspectives on health, diet, and human anatomy influenced by his love of travel and nature. He doesn’t shy away from the unsettling aspects of life, but approaches it all with reverence and curiosity. He’s also the author of The Unseen Body, a fascinating book I highly recommend.</p><p><em>“I’m very skeptical about what doctors have to say about nutrition.” -Jonathan Reisman</em></p><p>In the first part of this 2 part episode, we get deep in the weeds of the ongoing debate between carnivores and vegans. Is one diet better than the other for our optimal health, or is your gut and environment the best indication of what’s best for you?</p><p><br /></p><p><strong>Unique Perspectives from Jonathan:</strong></p><p>“The adaptability of the gastrointestinal tract is important, [...] our gastrointestinal tract does not look like a pure carnivore’s tract, it also doesn't look like a pure herbivore’s tract, so I think we are probably meant to be omnivores.”</p><p>“Variability is a really important thing.”</p><p>“Nutritional science through headlines is a very bad way to understand what’s good and what’s bad for us.”</p><p><br /></p><p><strong>Follow Jonathan Reisman</strong>: </p><p>Website: <a href="https://www.jonathanreisman.com/" target="_blank">https://www.jonathanreisman.com/</a> </p><p>Substack: <a href="https://jonathanreisman.substack.com/" target="_blank">https://jonathanreisman.substack.com/</a> </p><p>Twitter: <a href="https://twitter.com/jonreismanMD" target="_blank">https://twitter.com/jonreismanMD</a> </p><p>Instagram: <a href="https://www.instagram.com/jonreismanmd/" target="_blank">https://www.instagram.com/jonreismanmd/</a> </p><p><br /></p><p>SPONSORS:</p><p>Get 5 free AG1 Travel Packs and a FREE 1 year supply of Vitamin D with your first purchase at <a href="https://bit.ly/AG1Impact" target="_blank">https://bit.ly/AG1Impact</a>.</p><p>Get $300 into your brokerage account when you invest $5k within your first 90 days by going to <a href="https://bit.ly/FacetImpact" target="_blank">https://bit.ly/FacetImpact</a>.</p><p>Head to <a href="http://www.insidetracker.com/" target="_blank">www.insidetracker.com</a> and use code “IMPACTTHEORY” to get 20% off!</p><p>Sign up for a one-dollar-per-month trial period at <a href="https://bit.ly/ShopifyImpact" target="_blank">https://bit.ly/ShopifyImpact</a>.</p><p><br /></p><p><strong><em>Are You Ready for EXTRA Impact?</em></strong></p><p>If you’re ready to find true fulfillment, strengthen your focus, and ignite your true potential, the Impact Theory subscription was created just for you.</p><p>Want to transform your health, sharpen your mindset, improve your relationship, or conquer the business world? 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Key Insights
- Reisman argues that human gastrointestinal tracts are intermediate between carnivores and herbivores, supporting omnivory rather than strict adherence to any single dietary philosophy.
- Bilyeu hypothesizes that vegan diets may promote longevity through hormetic stress by avoiding constant mTOR activation, a theory Reisman finds plausible but acknowledges lacks clear scientific support.
- Reisman claims that medical schools provide inadequate nutrition education, making physicians generally unreliable authorities on nutritional science despite their medical training.
- Reisman states that optimal diets vary significantly based on lifestyle activity levels, with ancestral high-meat diets becoming less necessary in modern sedentary environments with access to diverse global foods.
- Reisman contends that modern medicine can only confirm the absence of nutritional deficiency, not the presence of optimal health or peak performance, representing a fundamental limitation of current medical assessment.
- Reisman explains that many animals (lions, orcas, other predators) preferentially target nutrient-dense organs like liver and bone marrow, suggesting evolutionary selection for nutritional efficiency in foraging behavior.
- Reisman argues that medical diagnosis relies as much on observational art (reading subtle signs like skin color, breathing patterns, overall appearance) as on objective testing, requiring years of experience to refine.
- Reisman proposes that AI could significantly advance population-level nutrition science and rare disease diagnosis by analyzing biomarkers in stool, breath, and other biological effluents across large datasets.
- Reisman claims that vegan diets are achievable in modern contexts through supplementation and nutritional knowledge but required ancestral humans to be in a stressed survival state rather than thriving.
- Reisman describes his medical philosophy as consultative, presenting multiple treatment options with transparent risk-benefit analyses rather than prescriptively directing patients toward single approaches.
- Reisman states that many commonly-held medical recommendations (like preferring olive oil to butter in children) are extrapolated from studies of unhealthy older adults to healthy populations without valid evidence.
- Reisman argues that understanding food origins, animal anatomy, and the circle of life provides both intellectual satisfaction and practical knowledge that can improve eating quality and health decision-making.
Topics
Transcript
What's up, everybody? I'm really excited for this two-part episode today with Dr. Jonathan Reisman. He's one of the most profoundly knowledgeable anatomists I have ever encountered. This guy literally drug a deer into the woods so that he could skin it and look under the hood. I wasn't sure if I was going to be interviewing Hannibal Lecter or Da Vinci, both known for their penchant for dissection, by the way. But thankfully, what I got was a deep dive into a host of fascinating topics revolving around how the human body works and what you can do with that knowledge to improve your own life. We even got into a discussion about primal living that puts the carnivore…
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