A comprehensive meta-analysis of 31 randomized crossover trials published in the Journal of Applied Physiology has provided new insights into how carbohydrate supplementation affects muscle fuel utilization during prolonged exercise. Researchers led by Dr. Jacob A. Rothschild found that carbohydrate ingestion reduces muscle glycogen depletion by approximately 9% during endurance activities such as cycling and running, averaging around 100 minutes in duration. While this reduction reached statistical significance at the aggregate level, the finding reveals important nuances about individual variability. Notably, 46 of 48 individual study comparisons failed to demonstrate significant glycogen sparing, underscoring substantial differences among athletes. Beyond glycogen conservation, the broader endurance sports literature confirms that carbohydrate supplementation enhances performance through multiple mechanisms, suggesting glycogen sparing represents only one component of carbohydrate’s ergogenic benefits. Read the full article on GMJ Newsroom.
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