Dr. Will Bulsiewicz — World-renowned gastroenterologist and gut-health author (known as 'Gut Health MD'). Author of multiple books on the microbiome, including his new release Plant Powered Plus, and co-founder of the prebiotic fiber company 38TERA.
The gist
Dr. Will Bulsiewicz returns to explain how the gut microbiome governs the immune system and how a damaged gut barrier ('leaky gut') drives chronic low-grade inflammation linked to over 130 diseases. He walks through fecal transplants, fiber and short-chain fatty acids, the truth about gluten versus fructans, and why 90-95% of people are fiber-deficient. He then lays out a detailed circadian 'perfect gut day' from morning light and hydration to evening supplements and sleep, plus the roles of loneliness, trauma, and the brain-gut axis. The conversation closes with an emotional account of reconciling with his late father.
Big reveals
- A patient's life-threatening C. diff infection was reversed overnight with a fecal transplant instead of removing her colon.
- A gastroenterology study found supposed gluten sufferers reacted to fructans, not gluten — 'we've misnamed it.'
- A study on alcohol convinced him to nearly quit: leaky gut tracked blood alcohol and only normalized when alcohol hit zero.
- Claims casual household lights at night can cut melatonin by 30%.
- Admits he stopped speaking to his father for 10 years; his wife and the birth of his daughter led him to reconnect before his dad's sudden death.
- Reads aloud the heartbreaking book dedication to his late father in his own voice.
Things worth remembering
- 60% of the weight of your stool is your microbiome, not leftover food.
- About 38 trillion microbes live in your large intestine; the gut barrier renews every 3 to 5 days.
- Your body produces about 3.8 million new cells every second, any of which could turn cancerous.
- In melanoma trials, fecal transplants from responders roughly doubled how many patients beat cancer.
- Constipation often precedes Parkinson's disease, which may actually start in the gut.
- US wheat is often sprayed with glyphosate (Roundup) to dry it, which can disrupt the microbiome.
- 95% of Americans and 90% of people in the UK are deficient in fiber.
- Loneliness harms longevity on par with routine cigarette smoking.
- The Bristol Stool Chart, with seven stool types, originated from a study in Bristol, UK.
- Zoe ran the largest-ever bowel-habits survey, asking 140,000 people in the UK about their poop.
Recommended in this episode
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Plant Powered Plus
Dr. Will Bulsiewicz
“I highly recommend everybody goes and gets this book. It's going to be published in the US here on the 13th of January” — Steven Bartlett 02:07:11Find it on Amazon
Fiber Fueled
Dr. Will Bulsiewicz
“And in your book published in um 2020, I believed 2020. You you wrote this thing. Could you read that in your own voice?” — Steven Bartlett 02:04:30Find it on Amazon
38TERA prebiotic fiber supplement
Dr. Will Bulsiewicz (38TERA)
“I would love to add a prebiotic fiber supplement to that water. So, like our company is called 38 Terra. You could add that there” — guest 01:10:57Find it on Amazon
Matcha green tea
“I encourage people to have a matcha green tea. I'm a big matcha believer. This is the of all the teas that exist. It has the highest polyphenol content” — guest 01:32:19Find it on Amazon