A 24-hour fasted healthy adult begins feeding. Which pathway(s) will most rapidly switch on to clear postprandial glucose, and what hormonal changes drive this?

• A. Glucagon secretion will surge and persist to stimulate hepatic gluconeogenesis and glycogenolysis, which alone clear dietary glucose from the bloodstream.
• B. Growth hormone will be the first hormone to act by directly breaking down ingested carbohydrates in the gut before they enter the bloodstream.
• C. Cortisol will immediately spike and lower blood glucose by increasing peripheral glucose uptake through non-hormonal channels, which is the primary immediate response to feeding.
• D. Insulin secretion will increase rapidly, promoting GLUT translocation in muscle and adipose and activating glycogenesis and lipogenesis in liver and adipose — these insulin-driven processes clear postprandial glucose fastest.

Answer: (D)