Which statement is true about the roles of carbohydrates, proteins and fats in an athlete's diet and hydration?

• A. Carbohydrates provide energy, proteins repair/build tissue, fats supply energy and hormones; hydration maintains performance and thermoregulation.
• B. Carbohydrates are unnecessary; proteins provide all energy; fats are primary energy source; hydration has no effect on thermoregulation.
• C. Only carbohydrates are needed; proteins and fats are unwanted; hydration causes dehydration.
• D. Carbohydrates provide energy but fats are not needed; proteins store energy.

Answer: (A)

Carbohydrates are the body's primary fuel for activity, especially at higher intensities, and they are stored as glycogen in muscles and liver to be used during exercise. Proteins mainly repair and build tissues, supporting muscle recovery and adaptation after training. Fats provide a dense energy source, especially useful for longer, steadier efforts, and they also play a role in hormone production and overall energy availability. Hydration is essential because it supports blood volume, sweating, and heat dissipation, helping to maintain performance and the body's temperature regulation during exercise.

This combination correctly reflects how each macronutrient contributes and why staying hydrated matters for performance. Statements that claim carbohydrates are unnecessary or that hydration has no effect on thermoregulation misstate how the body uses fuel and manages heat.