Nutrition & Diet

Carbs vs Fat for Endurance Athletes — Two Legends Debate the Evidence

Two of the world's most prominent sports nutrition scientists — Louise Burke and Tim Noakes — formally debated whether low-carbohydrate, high-fat diets impede endurance performance. The current scientific consensus favors carbohydrate availability as the primary fuel strategy for optimizing performance across both short, high-intensity and prolonged, lower-intensity events. The ketogenic low-carb approach can boost fat oxidation, tapping the body's more abundant fat stores, but evidence suggests carbohydrate intake during exercise still improves performance in prolonged events by preventing hypoglycemia. Both sides agreed that muscle can be trained to oxidize either fuel more efficiently. The core disagreement centers on whether maximizing carbohydrate oxidation offers advantages beyond simply preventing blood sugar crashes. The debate highlights that future research must improve how metabolism and performance are measured.