Training Science Podcast Keto-Adapted, Carb-Smart: What Actually Helps on Race Day - with Dr Matthew Carpenter & Prof Paul Laursen
Aug 15, 2025
In this engaging conversation, Dr. Matthew Carpenter, a PhD candidate at Kingston University, joins Prof. Paul Laursen to uncover the science of ketogenic diets and endurance performance. They explore how insulin drops rapidly on low-carb diets and the impact of carbohydrate strategies for keto-adapted athletes. The discussion dives into the delicate balance of glycogen levels during races, the surprising benefits of carb ingestion even for fat-adapted athletes, and the intriguing role of ketones in performance and cognitive function.
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Research Sparked By A Supervisor's Weight Loss
- Matthew's interest began after a supervisor lost significant weight by dropping carbs and sparked metabolic research.
- That case study led to master's work and later a PhD on keto adaptation in endurance athletes.
Rapid Insulin Drop And Early Performance Dip
- Insulin falls quickly when you drop carbs, driving a rapid shift to fat oxidation within days.
- Performance often dips in week one despite fat oxidation increasing, showing adaptation lags.
Ketones Prioritize The Brain Over Muscle
- Muscles of keto-adapted athletes oxidize ketones less than expected; ketones may preferentially fuel the brain.
- This prioritization explains modest ketone oxidation in muscle despite elevated circulating ketones.