A trainee wants to cut out carbohydrates because they believe muscles cannot use them for fuel. Which correction is appropriate?
- AMuscles begin using carbohydrate once fat stores run low
- BCarbohydrate fuels the brain, but muscles run on protein
- CKeto adaptation makes carbohydrate unnecessary for hard intervals
- DGlycogen and glucose are major fuels, more so as intensity rises
Show answer and explanations
Answer
D
Muscle glycogen and blood glucose are central fuels for exercise, and they become more important as intensity increases.
A
Carbohydrate and fat are used together; the body does not wait for fat stores to run out, which essentially never happens during exercise.
B
Protein contributes only a small share of exercise energy; muscle relies mainly on carbohydrate and fat.
C
Fat adaptation increases fat use but tends to impair high-intensity performance, which depends on carbohydrate.
D
Muscle glycogen and blood glucose are central fuels for exercise, and they become more important as intensity increases.