In athletic nutrition, maintaining glycogen stores helps spare energy from which macronutrient?

• A. Protein
• B. Carbohydrate
• C. Fat
• D. Vitamins

Answer: (A)

Maintaining glycogen stores keeps glucose readily available for muscle energy, especially at higher intensities. When glycogen is low, the body turns to amino acids from muscle protein to make glucose through gluconeogenesis, which increases proteolysis and muscle loss. By preserving glycogen, this protein breakdown is reduced, so protein is spared as a fuel source. Vitamins aren’t macronutrients and aren’t used for energy, while fat becomes more relied upon as glycogen stores dwindle, but the direct protein-sparing effect comes from maintaining carbohydrate/glycogen.