Which metabolic state is characterized by the breakdown of stored energy reserves?

• A. Post-absorptive state
• B. Absorptive state
• C. Resting state
• D. Active state

Answer: (A)

The metabolic state characterized by the breakdown of stored energy reserves is the post-absorptive state. This state typically occurs several hours after eating when the body has already absorbed the nutrients from the most recent meal, and insulin levels begin to decrease. During the post-absorptive phase, the body shifts its energy source from glucose obtained from the recent diet to stored glycogen and fat reserves as it requires energy for physiological functions and to maintain blood glucose levels.

In this state, various processes, such as glycogenolysis (the breakdown of glycogen to glucose), gluconeogenesis (the production of glucose from non-carbohydrate sources), and lipolysis (the breakdown of fat stores into fatty acids and glycerol), are activated. These processes ensure that the body remains adequately fueled during periods of fasting or between meals.

The absorptive state, in contrast, is characterized by the immediate post-meal period when the body is actively absorbing nutrients, primarily using glucose from dietary sources. The resting state typically does not specifically refer to metabolic processes related to energy storage or utilization, and the active state usually suggests a period of high energy expenditure rather than energy reserve breakdown.