The Poo Doctor: This Gut Mistake Leads To Cancer. The Cheap Spice That Helps Repair A Damaged Gut!
World-renowned gastroenterologist Dr. Will Bulsiewicz reveals how chronic inflammation driven by gut dysfunction is connected to over 130 diseases, including cancer, Parkinson's, and autoimmune conditions. He shares the four essential nutrients missing from modern diets—fiber, polyphenols, healthy fats, and fermented foods—and provides a detailed daily routine to optimize gut health and reduce inflammation.
1. Understanding Inflammation and Its Hidden Dangers
Dr. Will Bulsiewicz opens by explaining that inflammation is the health story of our time that isn't getting enough attention. When asked to explain inflammation like he's talking to a 10-year-old, he breaks it down beautifully:
"Steve, you have an immune system that protects your body. And inflammation is when we turn that immune system on and we make it active."
He clarifies that inflammation isn't always bad—it helps clear infections and heal wounds. The problem arises when the immune system stays activated 24/7 without a real threat. This chronic low-grade inflammation flies under the radar, manifesting in subtle ways:
- Increased fatigue
- Difficulty concentrating
- Poor sleep
- Aches and pains
- Skin issues
"It can fly below the radar where you don't realize that it's there. Your doctor may not realize that it's there."
And here's a surprising truth: you can be skinny and still have inflammation. Dr. Will points out that competitive bodybuilders often look incredible on the outside but are "falling apart on the inside," frequently suffering from digestive issues.
2. The Shocking Connection Between Gut Health and Inflammation
The conversation takes a fascinating turn when Dr. Will explains the undeniable connection between your gut and immune system. Using an anatomical model, he walks through the three layers of your body's defense system:
Layer 1: The Gut Microbiome 🦠 Your large intestine houses 38 trillion microbes—bacteria, yeasts, and other organisms that have been on the planet for 4 billion years. Their job is to support your physiology and feed your gut barrier.
Layer 2: The Gut Barrier This single layer of cells lining your entire intestine (about 6-8 meters long) acts like a castle wall—keeping bad stuff out while letting good stuff in. Here's the exciting part:
"Every 3 to 5 days, you have an opportunity to create a brand new gut barrier."
Layer 3: The Immune System When the gut barrier breaks down (what's commonly called "leaky gut"), things sneak across that shouldn't be there. The immune system recognizes these intruders and activates to attack—that's inflammation.
Dr. Will uses a powerful analogy:
"The immune system is your small army and they're there to defend you. And when we activate the army and they're actually going to war, you have to expect that there's going to be damage to the surrounding areas."
The beautiful thing is this process can be reversed. Heal the gut microbes → they repair the gut barrier → the immune system cools off. 🔄
3. Chronic Inflammation's Role in Cancer and Disease
When inflammation stays switched on, it creates a cascade of problems throughout your body. The immune cells release signals called cytokines, which call for help and recruit even more immune cells, creating a wave of inflammation you can feel everywhere.
The consequences depend on which tissues are affected:
- Liver inflammation = hepatitis
- Brain inflammation = mood disorders, Alzheimer's, Parkinson's disease
On cancer specifically, Dr. Will shares a mind-blowing fact:
"Your body produces 3.8 million cells every second. Your immune system has the responsibility of identifying where there's a problem and taking it out."
With that many new cells being created, some are bound to have genetic abnormalities that could turn into cancer. A healthy immune system catches and eliminates these problematic cells before they become dangerous. But when the gut is compromised, the immune system can't do its job properly.
Research in melanoma treatment showed something remarkable: patients who received antibiotics before immunotherapy didn't do well. When researchers moved in the opposite direction—giving fecal transplants from cancer responders to new patients—the results were incredible:
"Literally twice as many people were beating cancer relative to the expectation."
4. The Life-Saving Power of Fecal Transplants
Dr. Will explains one of the most dramatic demonstrations of gut microbiome power: fecal transplants. This involves taking a healthy person's poop and transferring it into someone who's sick.
He shares a remarkable case study about Michelle, a patient who took an antibiotic (clindamycin) for a skin issue. This wiped out her gut, allowing a dangerous bacteria called C. diff to multiply, causing life-threatening inflammation of her entire colon.
"She's clutching her belly and she's moaning and groaning and she has no clue where she is. She's sweaty. She's pale. Her vital signs are completely out of whack."
The choices were stark: emergency surgery to remove her colon, or a fecal transplant. Dr. Will performed the transplant during a colonoscopy, delivering healthy bacteria throughout her large intestine.
"By the next day, she was a normal human being. She was laying in bed. She was able to have a conversation. And after 2 days, she was so normal that we were able to send her home."
The entire life-threatening infection was corrected by restoring her microbiome.
A critical warning though: Dr. Will strongly advises against DIY fecal transplants at home despite what some Netflix specials might suggest. Professional medical supervision is essential.
5. Parkinson's Disease May Start in the Gut
Perhaps one of the most fascinating revelations is about Parkinson's disease, traditionally considered purely a brain condition.
"I'm here to tell you that this problem begins down here in the gut and involves the connections between the two."
Dr. Will notes that every single Parkinson's patient he's ever seen is constipated—and the constipation comes before the Parkinson's diagnosis. This doesn't mean constipation causes Parkinson's, but it shows the disease's manifestations begin in the digestive system before transferring to the brain.
Studies using fecal transplants in Parkinson's patients showed:
"A year later, they had a durable continued benefit in terms of their movement issues."
The research is showing benefits for both brain symptoms and gut issues like constipation, demonstrating the powerful gut-brain connection. 🧠↔️🦠
6. Why 60% of People Have Gut Problems
When the Diary of a CEO audience was surveyed, over 60% reported struggling with some kind of gut problem—bloating, discomfort, or irregular digestion. Another 14-15% self-diagnosed with irritable bowel syndrome (IBS).
Dr. Will emphasizes there's no one-size-fits-all solution:
"You're all going to read the same book, but the way in which this book touches you is going to be unique to you. There's going to be something in there that you're going to find that you're like, 'That's my moment. That's my aha moment.'"
For some people, the issue is diet. For others, it might be sleep, circadian rhythm, or even unaddressed trauma. The key is identifying what that one thing is for you personally.
7. The Truth About Bloating and Gas
Everyone experiences bloating occasionally, but chronic issues indicate a problem. Dr. Will identifies the number one cause of bloating: constipation.
And here's a revelation—you might be constipated without knowing it:
"There are so many people who are listening right now that are constipated and they don't even know it because they poop every day and they think that how often they poop is the definition. And that's not true."
Constipation is about incomplete emptying, not just frequency. If you're straining, producing small nuggets, and still feeling like you need to go—you're doing "partial poops" and likely constipated.
Why does constipation cause gas? 💨
"60% of the weight of your stool is microbial."
When poop sits in gridlock, those microbes have unlimited time to ferment whatever they contact, producing gas. This is why many people fart a lot in the morning until they have their first bowel movement.
Three main causes of gas and bloating:
- Motility issues (constipation being the primary one)
- Damaged microbiome unable to properly process fiber
- Dietary factors like lactose or fructans
8. The Gluten Myth: What's Really Causing Your Symptoms
Dr. Will tackles a huge misconception: most people who think they're gluten intolerant probably aren't.
"Here in Los Angeles, it's probably 80% of people that think they're gluten-free. Which they don't need to be."
A fascinating study in the top gastroenterology journal gave participants three breakfast bars:
- A placebo bar
- A gluten-loaded bar
- A fructan-loaded bar
People who believed they had gluten problems actually had fewer symptoms with the gluten bar than the placebo! But they were triggered by the fructan bar.
"We have been taking this concept of gluten intolerance and we've misnamed it. It's not a gluten intolerance, it's a fructan intolerance."
Fructans are long-chain carbohydrates found in wheat, barley, rye, garlic, and onions. They're actually prebiotic and good for you—but people with slightly damaged guts struggle to process them.
Why sourdough might work for you: Fermenting bread reduces fructan content, explaining why some people can eat sourdough but not regular bread.
The glyphosate problem 🌾: In the US, wheat is often sprayed with Roundup (glyphosate) to dry it faster. While the chemical was deemed safe for humans, it disrupts the gut microbiome:
"Glyphosate disrupts the microbiome, depletes the beneficial bacteria, and the ones that tolerate it the best are the inflammatory ones, the bad bacteria."
This might explain why some people can eat pasta in Italy but not in the US—European countries don't allow this spraying practice. Buying organic wheat products avoids this issue entirely.
9. How Fast Can You Repair Your Gut?
The good news about gut health is how forgiving your system can be:
"The choices that you make today will be reflected in your microbiome by tomorrow."
Gut microbes can create new generations in as little as 20 minutes. Combined with the gut barrier rebuilding every 3-5 days, positive changes can come remarkably fast.
However, the starting point matters. Someone with ulcerative colitis or Crohn's disease (inflammatory bowel diseases) has the deepest level of gut damage, called dysbiosis. While complete reversal may not be possible, deep remission—living without flares—absolutely is.
10. Antibiotics: A Double-Edged Sword
Dr. Will delivers a sobering warning about antibiotics:
"If you take antibiotics, your risk of developing an inflammatory bowel disease in the next year just doubled."
Nothing decimates the gut faster than antibiotics. They:
- Reduce gut diversity
- Disrupt the gut barrier by 50%
- Activate the immune system
This applies to both adults and children. The inflammatory bowel disease rates have been climbing dramatically—up to 55% increase between 1970 and 2010 in the United States.
Interestingly, these conditions barely exist in third world countries. But as nations industrialize, cases start ramping up—pointing to lifestyle and environmental factors rather than pure genetics.
11. Diet Trends: What's Helpful and What's Harmful
Dr. Will expresses frustration with the whiplash of diet trends:
"In 2020, it was like the vegan diet was in. In 2023, it was the carnivore diet. You couldn't have more diametrically opposed diets."
The science hasn't changed that dramatically—nor has human biology. Any person willing to change their diet for health deserves respect, but extreme restriction in either direction isn't the answer:
"I don't believe that a 100% meat or organ diet is in balance or the optimal solution for longevity. But on the flip side, a fruit-only diet, I would never support or recommend either."
The sweet spot is whole food in balance.
On juice cleanses and extreme diets: while they might temporarily make you feel better by removing irritating foods, they generally don't accomplish much long-term.
Good news from TikTok: The fiber maxing trend is actually on point! People are recognizing the benefits of dramatically increasing fiber intake. The only caution is to ease into it—sudden massive fiber increases can cause problems that lead people to give up.
12. The Four Things Missing From Your Diet
Dr. Will reveals the four essential elements missing from most people's diets that appear in ALL healthy dietary patterns—Mediterranean, pescatarian, flexitarian, and more:
1. Fiber 🌾
95% of Americans and 90% of people in the UK are deficient. Fiber is the principal food for good bacteria and the precursor to short-chain fatty acids—the most anti-inflammatory compounds Dr. Will has ever studied.
When fiber meets your gut microbes, they produce three critical short-chain fatty acids:
- Acetate
- Propionate
- Butyrate (Dr. Will's favorite—essential for producing proteins that hold your gut lining together)
"There's only one thing that exists on this plate that does not contain fiber."
Looking at a spread of plant foods, only pure oil contains zero fiber. Every fruit, vegetable, whole grain, seed, nut, and legume has fiber. Even mushrooms (technically fungi) share these beneficial characteristics.
2. Polyphenols 🌈
These phytochemicals define the colors of foods and impact the gut. Nearly everyone falls short of recommended fruit and vegetable intake. 95% of polyphenols require gut microbes to be activated—so a healthy microbiome is essential to benefit from them.
3. Healthy Fats 🥑
Extra virgin olive oil, avocados, seeds, nuts, and omega-3s from fish. These monounsaturated fats should be consumed freely in whole food form.
One caveat: If weight loss is your goal, limit oils (even healthy ones) since they're the highest-calorie substance on the planet.
4. Fermented Foods 🥒
The average fermented food intake in the United States is zero. A Stanford study showed that in just eight weeks of adding fermented foods:
"People could increase the diversity of their gut microbiome. That means a healthier gut. And they lowered inflammation."
Options include yogurt, kimchi, sauerkraut, pickles, kefir, and more.
13. What Alcohol Really Does to Your Gut
Dr. Will shares the study that changed his mind about alcohol—he now rarely drinks:
Researchers gave people significant alcohol and tracked blood alcohol levels alongside lipopolysaccharide (LPS) every 30 minutes. LPS comes from inflammatory gut bacteria and shouldn't be in your bloodstream—its presence indicates a weak gut barrier.
"As the blood alcohol level goes up, in parallel, the lipopolysaccharide goes up. When the alcohol peaks, so did the lipopolysaccharide."
The lipopolysaccharide didn't return to normal until blood alcohol hit zero. What this demonstrates is that alcohol causes leaky gut, and any detectable amount of alcohol can create inflammation.
"I don't think there's any amount of alcohol that's safe."
Heavy drinkers have totally destroyed guts—a necessary step on the pathway to cirrhosis and alcoholic liver disease.
14. The Truth About Turmeric 🧡
That orangey spice on the plate gets attention for good reason. Turmeric contains curcumin, a polyphenol that blocks inflammatory cytokines (those communication signals between immune cells).
"Turmeric helps to pull the batteries out of those walkie-talkies."
For people with chronic inflammatory conditions, consistent daily turmeric makes sense. However, Dr. Will cautions against overdoing turmeric supplements—too much can create problems.
15. Dr. Will's Perfect Gut Day: Morning Routine ☀️
Dr. Will outlines a comprehensive daily routine built around your circadian rhythm—the 24-hour clock your body evolved with based on the sun.
"Around 50% of our genes are turned off or on at specific times of day based upon our circadian rhythm. More than 50% of our microbes rise and fall during the course of our day to meet the moment."
7:00 AM - Wake Up Consistently
Consistency with wake time sets the foundation. Spend the first 5 minutes mentally preparing for your day.
7:05 AM -
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