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Timestamps are as accurate as they can be but may be slightly off. We encourage you to listen to the full context.
In this third conversation between Rich Roll and Dr. Will Bulsiewicz (Dr. B), we dive deep into the gut-immune connection as the root determinant of chronic inflammation—a silent driver behind three out of five deaths. Dr. B explains how our modern lifestyle disrupts the microbiome, leading to inflammation that manifests as everything from fatigue to chronic disease. (07:00) We explore practical solutions through four nutritional workhorses, the importance of circadian rhythm alignment, and why your microbiome is nocturnal. (109:00) The conversation takes an unexpectedly moving turn when Dr. B shares a deeply personal story about his decade-long estrangement from his father, serving as a powerful reminder that healing isn't just biological—sometimes it's emotional and spiritual.
Dr. Will Bulsiewicz is a board-certified gastroenterologist and one of the world's foremost authorities on the gut microbiome. He is the author of the bestselling "Fiber Fueled" and his latest book "Plant Powered Plus," which focuses on the gut-immune connection and chronic inflammation. Dr. B serves as the US Medical Director for ZOE and is the founder of supplement company 38 Terra, bringing cutting-edge microbiome research to practical applications for optimal health.
Dr. B explains that 70% of our immune system resides in the gut, making the microbiome the primary determinant of inflammation in our bodies. (11:20) When our gut barrier becomes compromised through poor diet and lifestyle choices, it triggers chronic low-grade inflammation that manifests as fatigue, brain fog, hormonal issues, and eventually chronic disease. The key insight is that inflammation rises and falls in parallel with gut microbe health—fix the microbiome, and you can dramatically reduce inflammation and disease risk.
Rather than focusing on what to eliminate, Dr. B identifies four key nutrients we're deficient in: fiber, polyphenols, healthy fats, and fermented foods. (59:00) These "workhorses" work synergistically to feed beneficial bacteria, strengthen the gut barrier, and reduce inflammation. The beauty is that eating a diverse array of plant foods naturally provides all four, making the approach both simple and sustainable.
One of the most fascinating revelations is that your microbiome is nocturnal—it's most active at night when it should be focused on recovery and restoration. (109:00) Eating late at night disrupts this natural rhythm and forces your microbes to deal with digestion when they should be healing your body. This creates a cascade of inflammation that can persist until 3 AM, explaining why late-night eating is so detrimental to health.
Getting sunlight exposure within the first hour of waking can increase your cortisol spike by 50%, setting your circadian rhythm and supporting both your microbiome and immune system. (107:00) Dr. B challenges listeners to try this for just one week, promising increased energy, better focus, and improved sleep starting from day one. This simple intervention helps synchronize your entire physiological system.
Perhaps the most powerful takeaway is that unresolved trauma and spiritual disconnection create chronic sympathetic nervous system activation, keeping your body in a perpetual state of inflammation. (133:00) Dr. B shares research showing that even early childhood trauma affects gut microbiome diversity and brain function decades later. True healing often requires addressing these deeper emotional and spiritual wounds alongside dietary and lifestyle interventions.