Endurance Unlimited

Fueling Insights Explained: Iñigo San-Millán on Optimizing Carbohydrate Intake for Cyclists — Season 7 Ep 9

Endurance Unlimited

Show Notes

You're not seeing things. CoachCast has been renamed Endurance Unlimited. Stay tuned for more great episodes and more. Now, on to this episode...

Dr. Iñigo San-Millán explains the science and strategy behind optimal cycling nutrition. Learn how TrainingPeaks' new Fueling Insights feature leverages decades of his metabolic research data to help athletes and coaches evaluate and individualize fueling plans based on athlete metrics, not guesswork. From breaking through the outdated 40-gram carb ceiling to personalizing race-day nutrition for every level of today's cyclist, learn how this tool is changing how we plan, perform and recover.

03:34 Iñigo Intro and Current Roles

07:50 Revamping Carbohydrate Intake for Athletes

12:41 Metabolic Flexibility

14:28 Pioneering Carbohydrate Oxidation Research

19:08 Fat Oxidation Misconceptions in Athletes

21:07 FATMAX: Peak Fat Oxidation Point

26:30 Race Performance and Energy Expenditure

27:48 Balancing Glycogen for Athletes

31:05 Cyclists' Nutrition & Intensity

38:31 Fueling Insights Workout Calculation Steps

39:48 Metabolism Variability Among Individuals

44:32 Risks of Fasted Workouts

47:16 Understanding Gross Efficiency Limitations

56:54 The Nutrition Evolution

Learn more about Fueling Insights

Learn more about TrainingPeaks

Episode 1, Season 5: The Biochemistry of Zone 2

More from Endurance Unlimited

Oct 7, 2026

Go inside the high-performance partnership of Hannah and Ben as they unpack the science and soul of world-class Kona prep. This episode isn’t just a talk—it’s a tactical roadmap from turning setbacks into strategy, optimizing recovery, and making every workout count. Hear how their trust, clear communication, and sharp use of TrainingPeaks help transform raw data into racing brilliance.

Sep 30, 2026

Trevor Foley's rise in long-course triathlon hasn't followed a typical playbook. A former college runner with almost no cycling background, he found his way into the sport with what he calls “blind confidence" — and quickly discovered a talent for producing serious power on the bike.

Sep 17, 2026

Dive into the next evolution of indoor cycling as we sit down with George Gilbert, the brains behind TrainingPeaks Virtual.

Aug 19, 2026

Ultra running and mountain athlete coaching redefined: discover Scott Johnston’s trusted training secrets for building champions at UTMB, Hardrock, and Western States.

Aug 7, 2026

Join pro cyclist Ruth Edwards and host Joe Lewis as they pull back the curtain on the 2026 Tour de France Femmes—every dramatic stage, gritty comeback, and the crucial behind-the-scenes support that’s powering a new wave of champions. You’ll get the inside scoop on game-changing workouts, the impact of investment and equality, and the data-driven tools elevating the women’s peloton to its fastest, deepest level ever.

See all episodes →