What macronutrient is typically converted to glucose for immediate energy use by the body's cells?

The correct answer is carbohydrates because they are the primary macronutrient the body uses for immediate energy. When consumed, carbohydrates are broken down into simpler sugars such as glucose, which is then readily available for use as a source of energy by the body's cells. This process is crucial, especially for cells in high-energy-demand spaces of the body, such as the brain and muscles during physical activity.

Fats serve as a longer-term energy reserve and are metabolized differently, typically being broken down into fatty acids for energy production at a slower rate compared to glucose. Proteins primarily function in building and repairing tissues and are not typically converted to glucose for immediate energy; they are only utilized for energy in situations of prolonged fasting or intense exercise when carbohydrates are scarce. Vitamins, while essential for numerous biochemical processes, do not serve as macronutrients or direct energy sources.