I’M DR. WILL BULSIEWICZ

But everyone calls me Dr. B.

Board-Certified Gastroenterologist • Gut Health Authority • Lifestyle Medicine Pioneer • New York Times Bestselling Author • Founder of 38TERA

I’m on a mission to help you unlock your best health and truly feel the difference. With over two decades of clinical experience, dual board certifications, a robust research portfolio, and numerous awards, I’ve earned recognition as a trusted leader at the crossroads of gut health, nutrition, and lifestyle medicine. My work blends cutting-edge science with clinical expertise and a whole-person approach to empower you to achieve thriving health and vitality that starts in the gut.

In addition to my clinical and educational work, I speak at conferences and professional events, sharing evidence-based insights on gut health, inflammation, energy, and long-term vitality.

I’m here to help you live healthier, longer, and more vibrantly, starting with your gut.

Rooted in Science, Focused on You

Medicine should never be “one size fits all.” You are a unique individual, and your gut microbiome is as distinct as your fingerprint. My goal is to uncover what works best for you and your microbes. That begins with truly understanding you: your symptoms, health history, and personal story. Only when we see the full picture can we identify what’s holding you back and why.

From there, we build a plan that is as individual as you are, targeted to address the drivers of your health. Missing elements are restored. Excesses are reduced. Harmful factors are addressed. Vital systems are optimized. This is not about quick fixes or masking symptoms. Your plan is rooted in science, shaped by a whole-person perspective, and aimed at restoring your energy, resilience and vitality.

It may include advanced nutrition protocols, lifestyle optimization, targeted supplementation, and medical therapy where needed — all working together to help you achieve lasting results.

Years ago, I was 50 pounds overweight and struggling with food intolerances and gut symptoms. I was depressed and anxious, with little energy and no self esteem.

By applying the same evidence-based strategies I now teach, I reclaimed my health. I’ve seen my patients do the same: reverse symptoms, feel energized, and rebuild their relationship with food.

That’s why I made it my mission to share this knowledge far beyond the clinic.

ACADEMIC & PROFESSIONAL DISTINCTIONS

I earned the highest clinical honors in both my residency at Northwestern and my gastroenterology fellowship at UNC—recognition reserved for the top physician in each graduating class. I was also inducted into Alpha Omega Alpha, the nation’s most prestigious medical honor society, an achievement that marks the top tier of physicians for excellence in scholarship, leadership, and patient care.

Board-certified in both internal medicine and gastroenterology, I’m the author of more than 25 peer-reviewed publications, with my research cited over 5,000 times by other scientists. I’ve delivered more than 50 scientific presentations, from keynotes at major conferences to briefings for Congress, the USDA, and the NFL Alumni.

Nationally Recognized Author & Educator

My books, Fiber Fueled and The Fiber Fueled Cookbook, have over 500,000 copies in print, been translated into 20 languages, and both earned spots on the New York Times bestseller list.

My forthcoming book, Plant Powered Plus, explores how inflammation is the root of countless diseases — and why the gut is the key to reversing it. I view my books as more than words on a page; they’re tools for healing.

The ability to share this message with readers around the globe is not just an honor—it’s at the heart of my mission to help as many people as possible.

Making Science Digestible

I believe knowledge is one of the most powerful tools for healing.

That’s why I’ve created online programs that empower people to take charge of their health and transform their lives. These courses address some of the most common challenges I see—constipation, acid reflux, bloating, and food intolerances—through a holistic, evidence-based approach.

They’re designed not just to ease symptoms, but to restore balance, build resilience, and help you feel your best every day.”

Shaping the Future of Gut Health

I’m the Founder of 38TERA, a science-driven supplement brand that’s oriented through the gut. Prebiotic and probiotic supplements are mainstream tools in gastroenterology, but I saw the supplement market flooded with outdated products lacking scientific rigor, transparency, and third-party testing. That’s what motivated me to create 38TERA, and I’m proud of what we’ve built: high-quality, evidence-based formulations, uncompromising ingredient and manufacturing standards, and a commitment to transparency. Most of all, I’m proud of the thousands of people whose health has benefited from our work.

In 2021 I joined the Scientific Advisory Board of ZOE, the personalized nutrition platform behind the world’s largest microbiome study, and in 2022 I became their US Medical Director. ZOE has helped translate groundbreaking microbiome research into practical, personalized tools that empower people to make food choices tailored to their biology. I’m proud of the work I’ve done with ZOE and what we’ve accomplished in our quest to deliver actionable advice and improve the health of millions.

Together, these two roles have allowed me to influence the gut health landscape from both the research and product sides, driving innovation that’s deeply rooted in science and focused on real-world impact.