Rethinking the Role of Carbohydrates in Endurance Exercise

For over a century, the sports science community has emphasized muscle glycogen as the critical fuel for endurance exercise, positing that its depletion triggers inevitable fatigue and that high carbohydrate (CHO) intake is essential to sustain performance. However, a comprehensive review of more than 160 studies spanning 100 years, published in Endocrine Reviews in 2026 by Timothy D. Noakes and colleagues, challenges this paradigm. The analysis reveals that exercise-induced hypoglycemia (EIH)—a drop in blood glucose levels—correlates more strongly with fatigue than muscle glycogen depletion alone. CHO ingestion primarily benefits performance by stabilizing blood glucose and preventing EIH, rather than replenishing muscle stores, with implications for dietary recommendations favoring lower, targeted CHO doses during prolonged efforts to optimize endurance without excess.

Diet, General HealthScott Solomons, DDSSeptember 28, 2026Carbohydrates, Exercise Metabolism, Physical Performance, Hypoglycemia, Glycogen Depletion, Endurance Exercise, Fat Oxidation, Blood Glucose, Sports Nutrition, Hepatic GluconeogenisisComment