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.
What this episode covers
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.
Recommended on this episode
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
The guest's own work
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
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
Big reveals from this episode
- 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.
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.