The Dylan Gemelli Podcast

Episode #101 Featuring Dr. William Li: Insights from a True Scientist
Date: March 16, 2026
Host: Dylan Gemelli
Guest: Dr. William Li (physician, vascular biologist, best-selling author of "Eat to Beat Disease" and "Eat to Beat Your Diet")

Episode Overview

This highly anticipated episode welcomes Dr. William Li, a renowned physician-scientist and best-selling author, for a masterclass on cutting-edge nutrition science, gut and heart health, the real story on spinach/oxalates, and the art of simplifying diet for optimal well-being. Dylan Gemelli takes a deep dive with Dr. Li into new research about the microbiome (including the brain’s), practical strategies for healing the gut, the truth behind common food fears, and how to select olive oil for maximum health. The conversation stands out for its clarity, data-driven approach, and actionable, easy-to-understand guidance.

Key Discussion Points and Insights

1. Dr. Li’s Scientific Mindset and Approach

• Dr. Li emphasizes humility and curiosity in science, continuously seeking new questions rather than relying on fixed dogma.
  • Quote: “Real scientists like me…spend most of our time scratching the itch of curiosity and figuring out like what questions we need to ask next.” — Dr. William Li [03:42]
• Medical knowledge constantly evolves; what’s accepted one decade may be overturned the next.

2. The Evolving Science of the Human Microbiome

The Gut-Brain-Immune Superhighway

• Dr. Li describes the transformation in thinking: from believing all bacteria were bad, to understanding humans are host to 39 trillion mostly beneficial bacteria (the microbiome).
• Most healthy bacteria reside in a pouch of the colon known as the ilium, close to the appendix, raising new theories about the appendix as a “bacterial ammo clip.”
• 70% of the immune system is located in the gut wall, not the lymph nodes or spleen.
  • Quote: “70% of our immune system is actually found inside the wall of our gut. Not in our lymph nodes, not in our spleen.” — Dr. Li [11:02]
• The vagus nerve is a two-way communication channel between gut and brain:
  • 80% of nerve signals go from the gut to the brain, not the other way around.
  • Gut bacteria “text message” the brain, largely controlling mood, cognition, and possibly disease vulnerability.
  • Quote: “Only 20%…of the electrical signals going along your vagus nerve come from your brain…80%…go from the gut back to the brain.” — Dr. Li [14:07]

The Surprising Brain Microbiome

• Recent findings: Even the brain has its own microbiome—not many bacteria, but healthy ones, likely performing regulatory functions.
• Other “sterile” body areas (breast milk, semen, bladder) have their own natural microbiomes.
• Paradigm shift: Not all bacteria are enemies; many are vital for our health at sites never before considered.
  • Quote: “The assumption that all bacteria are bad: totally off base…we have to be looking for…bacteria in places we didn’t expect…” — Dr. Li [16:14]

3. Gut Health: What Is Leaky Gut and How Should We Care for Our Gut?

• Leaky gut explained as a weakening or perforation of the gut lining, allowing inflammation and immune disruption.
• The omentUM, an organ “like an octopus or baseball glove,” patrols the abdomen to seal major gut leaks—nicknamed “the policeman of the abdomen.”
  • Quote: “This thing is like a baseball glove that moves around your belly continuously…when it finds a perforation…it’ll wall off that perforation so you don’t wind up having life-threatening injury.” — Dr. Li [29:52]

Practical Solutions:

• The body wants to heal itself. Encourage this by enabling regeneration and lowering inflammation.
• Key Gut-Healing Foods and Strategies:
  • Fermented foods (esp. whole-fat yogurt): help restore microbiome balance; avoid low-fat, sweetened yogurts with additives.
    • Quote: “Whole fat yogurt…does not raise your cholesterol, lowers [it]…lowers the risk of heart disease.” — Dr. Li [34:18]
  • Prebiotics (fibers from colorful plant foods): serve as fertilizer for gut bacteria.
  • Avoid gut irritants: excess alcohol, ultra-processed foods, diet sodas, artificial sweeteners, and excessive meat loads.
  • Supplements (pre-, pro-, postbiotics): “for topping off,” not as a replacement for food-derived nutrition.

4. Debunking Food Fears: Spinach, Oxalates, and Beyond

• The spinach/oxalates debate: Most people tolerate oxalates fine; only a small minority are sensitive. The health benefits of spinach (esp. as a source of dietary nitrates) far outweigh the risks for most.
  • Quote: “For most people, oxalates and spinach [are] perfectly fine…spinach has got all kinds of other goodies…great source of natural dietary nitrates.” — Dr. Li [41:38]
• Chewing spinach (or beets): Releases dietary nitrates, which gut and mouth bacteria convert to nitric oxide—lowers blood pressure, protects the brain, recruits stem cells for bodily repair, and may help prevent stroke.
  • Quote: “Nitric oxide is a natural signaling molecule…relax[es] blood vessels…decrease your risk of fatal stroke by 4% for every 1 point drop in systolic blood pressure.” — Dr. Li [45:27]

5. Heart Health and Stem Cell Activation via Food

• Dietary strategies (spinach, beets, arugula, dark chocolate, olive oil) increase nitric oxide and polyphenols, triggering stem-cell recruitment and vessel resilience.
• Clinical studies: Two cups of high-polyphenol hot chocolate daily doubled stem cells in the blood and restored vascular resilience in patients with heart disease.
  • Quote: “You give them two cups of hot chocolate a day…for a month…they can have double the number of stem cells in their bloodstream for healing and regeneration.” — Dr. Li [53:50]
• Olive oil pro tips: Not all are equal! Look for mono-varietal extra virgin olive oil from
  • Spain: “Picual” olive
  • Italy: “Moriolo” or “Coratina” olives
  • Greece: “Koroneiki” olives
  • Choose brands tested for heavy metals and microplastics (e.g., Costarena).
  • Recommended dose: 3–4 tablespoons per day.

6. Simplifying Nutrition and the Power of Cooking

• Science is complex but practical advice can be simple: Focus on whole foods, variety, color, and learning basic cooking skills.

• If you want to amplify your ability to “biohack,” learn to cook—experiment with unfamiliar produce and recipes for more excitement (and health benefits).

• Quote: “If I could encourage you…add one activity…learn how to cook. It’s not hard…watch somebody who knows what they’re doing teach you in a couple of minutes…” — Dr. Li [67:30]

• Try new foods, question assumptions about personal preferences, and focus on how your body feels in response—often surprises and health improvements await.

Example:

• Omega-3s in Salmon: The healthiest fats are concentrated in the skin—so crisp it up for maximum benefit.
  • Quote: “The omega-3s are hugely in the skin…dry it well, cook skin-side down, get it crisp—now you’re getting the omega-3s.” — Dr. Li [71:14]

7. The Truth about Supplements

• Use supplements only as a “top-off” if dietary intake isn’t sufficient. Prioritize real food first—let “Mother Nature do the heavy lifting.”
  • Quote: “Start with food…then anything you need to top off, that’s what the word supplement means right off.” — Dr. Li [74:34]

8. Dr. Li’s Books (and Philosophy)

• "Eat to Beat Disease": Not about disease, but about nurturing health via five key defense systems: angiogenesis (circulation), stem cells, microbiome, DNA protection, and immune system.

• "Eat to Beat Your Diet": Not a typical diet book—explains how metabolism truly works (four phases from birth to death), busts myths, and teaches metabolic health without fads.

  • Quote: “Eat to Beat Disease…it’s really about how our body responds to what we put inside it…how our body has five health defense systems…” — Dr. Li [76:32]
  • Quote: “My second book is about body fat and how everything we thought we knew about body fat rings true and how fat is actually an organ in our body…” — Dr. Li [78:39]

9. Where to Learn More / Connect

• YouTube, Instagram, TikTok, Facebook: @DrWilliamLi
• Website: DrWilliamLi.com — includes Grand Rounds “masterclass” programs for practical, science-based strategies.

Memorable Quotes & Moments

• “Assume nothing, expect anything. That’s what a real scientist does…” — Dr. Li [18:14]
• “If you eat too much of something, yeah you’re going to have a problem. But here’s the benefit…” — Dylan Gemelli [67:04]
• “Life is for the living…if you’re spending all your time stressed out, looking for the most complicated thing…that takes away from quality of life.” — Dr. Li [73:16]
• Dr. Li walking through how to shop for olive oil—down to olive varieties and countries [59:21–64:48]
• Dr. Li’s dark chocolate hot chocolate prescription for cardiovascular regeneration [53:50–56:42]

Quick Reference: Timelines for Featured Segments

• Dr. Li Introduction & Philosophy on Science [02:46–05:11]
• Gut Microbiome & Brain Microbiome Explained [05:59–18:42]
• Leaky Gut, the Omentum, and Gut Healing Approaches [23:33–39:10]
• Spinach, Oxalates & Nitric Oxide Pathway [41:00–47:47]
• Heart Health, Stem Cells, Dark Chocolate, Olive Oil Deep Dive [48:25–64:48]
• Food Simplification & Practical Nutrition [66:17–74:34]
• Dr. Li’s Books & Big Ideas [76:24–81:38]
• Where to Find Dr. Li/Outro [83:30–84:47]

Conclusion

This episode is a top-tier resource for anyone interested in leveraging the latest nutrition and health science for a longer, healthier, and more empowered life. Dr. Li’s fact-focused answers, disdain for hype, and practical wisdom—plus Dylan’s relatable, no-nonsense hosting—make complex science accessible, actionable, and motivating. For every myth debunked or trend scrutinized, Dr. Li offers a constructive, easy-to-follow takeaway using real food and simple habits. Highly recommended for anyone interested in true evidence-based health optimization.