NCSF Sport Nutrition Specialist Certification (SNS) Practice Test

Which mechanism does the body employ during metabolic homeostasis when blood glucose levels are normal?

1. Fat-sparing mechanism

2. Protein-sparing mechanism

3. Carbohydrate-sparing mechanism

4. Energy-sparing mechanism

The correct answer is: Protein-sparing mechanism

During metabolic homeostasis, when blood glucose levels are within the normal range, the body employs the protein-sparing mechanism. This mechanism utilizes carbohydrates and fats as primary sources of energy, thus preserving protein for its essential roles in the body, such as tissue repair and building enzymes and hormones. When glucose levels are stable, the body's reliance on carbohydrates helps to minimize the breakdown of proteins for energy, which is particularly important for maintaining muscle mass and supporting other critical physiological functions. If the body were to use protein as a primary energy source, it could lead to muscle breakdown and a decrease in overall metabolism efficiency. Maintaining a balance of macronutrients is crucial for effective energy utilization while sparing protein prevents unwanted catabolism, particularly important for athletes and individuals engaged in regular physical activity. This preservation of protein is essential for recovery and performance, showcasing why the protein-sparing mechanism is vital during periods of metabolic stability.