Final answer:
A high-carbohydrate diet is associated with the highest muscle glycogen levels because carbohydrates are stored as glycogen in muscles, which is vital for energy production during exercise.
Step-by-step explanation:
Of the diets listed, d. high-carbohydrate diet is associated with the highest muscle glycogen levels.
This is because carbohydrates are the most common source of energy to fuel the body and take the form of either complex carbohydrates, like starch and glycogen, or simple sugars like glucose and fructose.
When we consume a high-carbohydrate diet, excess glucose can be stored in the liver and skeletal muscles as glycogen, thus maximizing the muscle glycogen stores.
Approximately 70% of the total glycogen in the body is stored in muscle cells. Liver glycogen provides glucose to maintain blood glucose levels, while muscle glycogen is a readily available source of glucose during vigorous exercise.
Glucose is vital for producing energy in the form of ATP through glycolysis and the Krebs cycle during exercise.