Why Runners Get Stomach Problems (And How to Fix It): Dr Marc Bubbs
Run Long Run Healthy
Detective work: identifying problem foods
Dr. Bubbs recommends starting at breakfast, using a 3–4 hour window and removing fermentable foods to find triggers.
Brady Holmer sits down with Dr. Marc Bubbs — performance nutritionist, author, and creator of ProBio Nutrition — to break down everything runners need to know about gut health. From identifying food triggers to fueling on race day without GI disaster, Dr. Bubbs shares 20+ years of experience working with Olympians, pro athletes, and everyday runners. Whether you're dealing with chronic bloating or trying to push your carb intake past 60g/hour, this episode has you covered.
Brought to you by ProBio Nutrition - your all-in-one daily supplement for runners. Get 40% off with code RLRH (or 50% off + free shipping with a subscription) ➡️
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📚 Dr. Bubbs' books: Peak and Peak 40
🌐 drbubbs.com | probionutrition.com
📱 Follow Dr. Bubbs on Instagram & YouTube: @drbubbs
0:00 Introduction & Dr. Mark Bubbs' Background
1:07 Crossover Between Elite Athletes & General Population
2:04 Gut Health as a Buzzword — What Does It Actually Mean?
2:47 The 4 Pillars of Good Gut Health (King's College Framework)
5:47 Three Gut Health Scenarios: Poor → Good → Great
6:19 Scenario 1: Red & Yellow Flags — When to See a Doctor
9:14 The Difficulty of Identifying Problem Foods
9:54 Exercise-Related vs. Everyday GI Symptoms
11:42 Why You Should Start With Breakfast
12:07 The 3-4 Hour Detective Method
13:59 Can GI Symptoms Actually Be Resolved?
15:02 Eating Out vs. Cooking at Home
16:09 Are Food Sensitivity Tests Worth Your Money?
18:37 Scenario 2: When Running Triggers GI Distress
19:48 How Getting Fitter Improves Gut Diversity
20:57 GI Symptom Rates: Ultras, Ironman, Team Sports & Running
22:50 Finding Your Carb Intake Inflection Point
24:17 Gut Training: Titrating Up From 60g/hr
25:36 Is Pushing Above 80g/hr Worth the Risk?
26:00 Fueling Advice for Slower Marathon Runners
26:56 — AD BREAK —
28:08 Best Ways to Train Your Gut
29:06 Race Day Anxiety & the Gut-Brain Connection
31:20 Building Gut Health Over Months of Training
31:41 The 30 Food Diversity Challenge
33:08 Does Getting Fitter Reduce GI Symptoms? (The Bell Curve)
35:12 Probiotics for Colds, Travel & Performance
36:30 Race Week & Race Morning: What to Do and Avoid
38:47 Pro Tip: Caffeinated Gum Before the Start Line
39:06 The Golden Rule — Don't Try Anything New on Race Day
39:30 Carb Mouth Rinsing: The Placebo That Works
40:00 Scenario 3: Optimizing Gut Health for Performance
41:08 Prebiotics Explained — Seeds for Your Gut Garden
43:47 Best Whole Foods for Gut Health (By Category)
46:28 The Truth About Processed Food & Your Gut
47:47 Knowledge vs. Execution: The Real Friction Point
49:00 ProBio ProBlend: Why Dr. Bubbs Created It
53:00 Where to Find Dr. Bubbs, His Books & ProBio
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