Last week I had the brilliant Dr. Will Bulsiewicz on The BeingBrigid Show and it quickly became my most downloaded episode yet. Dr. B is a gastroenterologist, NYT bestselling author of Fiber Fueled, author of his upcoming book Plant Powered Plus, and a father of four. Follow him here. 

Beyond his impressive credentials, what struck me most is his generosity—after recording, he spent 90 minutes walking me through the book-writing process simply because he believes I need to write one. And this was our very first meeting.

What makes him so compelling is his balance: a science-first physician who also champions lifestyle and functional medicine principles. I often find that too often, conventional medicine dismisses nutrition, while a lot of doctors in the functional medicine world overreach beyond the evidence. Dr. B sits in the middle—grounded in research yet open to personalization (even if the personalization goes against the “evidence”). There are many layers of complexity to this. And it’s the approach that I try to take too which makes me really appreciate his approach. 

While I know you will get immense value from listening to the episode or watching it on youtube, I also wanted to outline five important takeaways, distilled into clear actions you can use today.

1) Your Microbiome is the Control Center

Twenty years ago, we didn’t have the tools to even see the microbiome. Today, it’s clear: ~38 trillion microbes in your gut influence digestion, metabolism, inflammation, hormones, mood, cognition, and even how genes are expressed. Translation: the state of your gut is a leading indicator of your overall health.

What this means for you:

+Treat your gut like your control center: what you eat, how you sleep, how you manage stress, and how you move are sending signals to 38 trillion decision-makers.

+Aim for daily inputs that build microbial fitness: fiber variety, colorful plants (polyphenols), quality proteins, healthy fats, and consistent sleep/wake cycles.

2) Nutrition isn’t Optional Care—it’s Foundational Care

Dr. B highlighted how upsetting it is that someone with acid reflux can walk into their doctor’s office, receive a Nexium prescription and be told: take it for the rest of your life without any other plan. IBD (Crohn’s, ulcerative colitis) is another example, which he explains is fundamentally a microbiome-based disease. 

In real-world clinics, patients who combine medical therapy with nutrition strategies achieve dramatically higher remission rates than medication alone. For inflammatory bowel disease, a lot of doctors say, “Hey, just take your injection.” But there’s data, there’s a study from Japan, where just take your injection at one year, about 60% of people end up in remission. So those drugs do work. But if you were to combine that with nutrition, you get up to 96%. If you could have a 16 in 25 chance of being in remission next year or a 24 in 25 chance, which would you choose?

The same principle applies broadly: food is not a competitor to conventional care; it’s a foundational part that can make everything better. 

What this means for you:

+Think “both/and,” not “either/or.” While medications can be lifesaving; nutrition addresses root drivers and improves outcomes.

+Build a care team: a doctor who respects nutrition + a Registered Dietitian who can personalize your nutrition and lifestyle plan.

3) Inflammation, Permeability & “Leaky Brain”: Why Fatigue and Brain Fog Show Up

Chronic inflammation is the most pressing issue of our time. In writing his new book, Plant Powered Plus, Dr. B discovered over 130 health conditions where he can point to the study to prove that it’s connected to inflammation. And he can point to the study to prove that it’s connected to the gut microbiome. There is a triangle that exists between the gut microbiome and our immune system, meaning inflammation, and many of these chronic diseases that we are struggling with

Your gut barrier is a one-cell-thick wall that protects an immune system that mostly lives along your gut lining. And it’s renewed every 3–5 days. When that barrier weakens, this creates increased intestinal permeability, also known as leaky gut, your immune activation ramps up. The same tight-junction biology exists in your blood-brain barrier—so a “leaky gut” can set the stage for a “leaky brain.” The first symptom most people feel? Low energy. Fatigue is commonly related to higher levels of inflammation. And this is often followed by brain fog, headaches, skin issues, joint pain, and hormone disruptions.

What this means for you:

+Prioritize barrier repair: consistent fiber, polyphenols, omega-3s, adequate protein, micronutrients (e.g., magnesium), and sleep.

4) Elimination Diets are a Tool, Not a Lifestyle

Short-term, strategic eliminations (FODMAPs, low histamine, gluten-free, etc.) can reduce symptoms while you restore microbial fitness, if you’re adding back foods methodically. Long-term restriction shrinks microbial diversity and can worsen tolerance over time.

What this means for you:

+If you remove it, have a plan to reintroduce it. The long-term goal is a broader, more flexible diet with fewer symptoms, not a smaller and smaller menu. This is where working with a Functional Medicine Registered Dietitian can be invaluable to better understand your triggers and how to reintroduce foods in a way that minimizes symptoms. 

+Increase plant diversity gradually. Start with going from 0% to 10%, then to 20–30% plant-predominant—at the pace your body can handle.

5) Blood Sugar ? The Whole Story—Your Microbiome Matters

You can “flatten” glucose by eliminating carbs, but that often ignores collateral damage: depleted glycogen, hormonal stress (especially for women), impaired performance, and an underfed microbiome. Microbes convert fibers and polyphenols into short-chain fatty acids, potent anti-inflammatory signals that can help turn off systemic inflammation. 

What this means for you:

+Keep carbs quality-focused, not fear-based: legumes, lentils, root veggies, intact whole grains (depending on what you can tolerate), fruit, and a rainbow of non-starchy vegetables.

Where to Go From Here 

When you consistently feed your microbes and respect your body’s biology, the wins compound: energy returns, brain fog lifts, digestion stabilizes, and inflammation calms. That’s not exaggerated, that stems from true science. 

Be sure to pre-order Dr. B’s new book, Plant Powered Plus: Activate The Power of your Gut to Tame Inflammation and Reclaim Your Health. 

And if you are interested in working with a knowledgeable Registered Dietitian  to help support you in optimizing your gut, identifying your triggers, and supporting blood sugar balance, go to our Programs Tab to learn more.