When does glycogenolysis begin during fasting?

When does glycogenolysis begin during fasting?

• A. Within 24 hours
• B. Within 6-8 hours
• C. Within 2-3 hours
• D. After 48 hours

Answer: (C)

Glycogenolysis starts early in the fast to keep blood glucose steady. When you stop eating, insulin levels fall and glucagon rises, signaling the liver to break down stored glycogen into glucose quickly. This rapid response begins within a few hours, commonly around two to three hours after the last meal, so the body can maintain glucose supply for the brain and other tissues while fasting continues. As fasting extends, those glycogen stores are depleted and gluconeogenesis becomes the main source of glucose.

Glycogenolysis starts early in the fast to keep blood glucose steady. When you stop eating, insulin levels fall and glucagon rises, signaling the liver to break down stored glycogen into glucose quickly. This rapid response begins within a few hours, commonly around two to three hours after the last meal, so the body can maintain glucose supply for the brain and other tissues while fasting continues. As fasting extends, those glycogen stores are depleted and gluconeogenesis becomes the main source of glucose.