Carbohydrate Ingestion Eliminates Hypoglycemia & Improves Endurance Exercise Performance in Triathletes Adapted to Very Low & High Carbohydrate Isocaloric Diets.

Very-low-carbohydrate diets (LCHF; <50g/day) have been debated for their potential to lower pre-exercise muscle and liver glycogen stores and metabolic efficiency, risking premature fatigue. It is also hypothesized that carbohydrate ingestion during prolonged exercise delays fatigue by increasing carbohydrate oxidation, thereby sparing muscle glycogen. Leveraging a randomized crossover design, we evaluated performance during strenuous time-to-exhaustion (70%⩒O) tests in trained triathletes following 6-week high-carbohydrate (HCLF, 380g/day) or very-low-carbohydrate (LCHF, 40g/day) diets to determine (i) if adoption of the LCHF diet impairs time-to-exhaustion performance, (ii) whether carbohydrate ingestion (10g/hour) 6-12x lower than current CHO fuelling recommendations during low glycogen availability (>15-hour pre-exercise overnight fast and/or LCHF diet) improves time-to-exhaustion by preventing exercise-induced hypoglycemia (EIH; <3.

Low and high carbohydrate isocaloric diets on performance, fat oxidation, glucose and cardiometabolic health in middle age males.

High carbohydrate, low fat (HCLF) diets have been the predominant nutrition strategy for athletic performance, but recent evidence following multi-week habituation has challenged the superiority of HCLF over low carbohydrate, high fat (LCHF) diets, along with growing interest in the potential health and disease implications of dietary choice. Highly trained competitive middle-aged athletes underwent two 31-day isocaloric diets (HCLF or LCHF) in a randomized, counterbalanced, and crossover design while controlling calories and training load. Performance, body composition, substrate oxidation, cardiometabolic, and 31-day minute-by-minute glucose (CGM) biomarkers were assessed.