CSSD Macronutrient Timing 3

Question 1

Which branched-chain amino acid acts as the primary leucine-sensing trigger for mTORC1 activation and subsequent muscle protein synthesis?

Accepted Answer

Leucine

Answer

Leucine is the key anabolic trigger that activates the mTORC1 signaling pathway, making it the most critical BCAA for initiating muscle protein synthesis.

Question 2

A cyclist completing a 3-hour race consumes carbohydrate only in the final 30 minutes. What is the primary consequence of this poorly timed intake?

Accepted Answer

Suboptimal glycogen sparing in the first two hours

Answer

Without early carbohydrate supplementation, muscle glycogen is depleted faster in the first two hours, impairing performance well before the late intake can counteract it.

Question 3

In the context of pre-exercise nutrition, why is a low-glycemic index meal preferred 3–4 hours before competition compared to a high-GI meal?

Accepted Answer

It sustains blood glucose and avoids pre-exercise hyperinsulinemia

Answer

A low-GI pre-exercise meal maintains steady blood glucose without an insulin spike that could suppress fat mobilization and cause rebound hypoglycemia at exercise onset.

Question 4

Which protein source has the highest leucine content per 100g of protein, making it particularly effective for post-exercise MPS?

Accepted Answer

Whey protein

Answer

Whey protein contains approximately 10–11% leucine by amino acid content, the highest of commonly used protein supplements, supporting rapid and robust MPS activation.

Question 5

Carbohydrate ingestion immediately post-resistance training primarily benefits which physiological process?

Accepted Answer

Blunting cortisol and replenishing muscle glycogen

Answer

Post-resistance exercise carbohydrates blunt cortisol-induced catabolism and replenish muscle glycogen, supporting recovery even though glycogen use during resistance training is modest.

(CSSD) Board Certified Specialist in Sports Dietetics Practice Test

(CSSD) Board Certified Specialist in Sports Dietetics Practice Test

CSSD Macronutrient Timing 3