In what state is lipid metabolism primarily increased?

• A. Absorptive state
• B. Post-absorptive state
• C. Fasting state
• D. Fed state

Answer: (B)

Lipid metabolism is primarily increased during the absorptive state. This state occurs shortly after a meal when nutrients, including carbohydrates, proteins, and lipids, are being absorbed into the bloodstream. During this period, the body has a surplus of energy sources, leading to increased storage of nutrients, particularly fats in adipose tissue. Insulin, which is elevated after eating, promotes the synthesis of fatty acids and their conversion into triglycerides, thereby boosting lipid metabolism.

In contrast, during the post-absorptive and fasting states, the body shifts away from using lipids for storage and begins to break down fat to maintain energy levels as it relies more on stored energy, including glycogen and lipids. While these states do involve lipid metabolism, the predominant focus is on mobilizing and utilizing stored energy rather than increasing lipid synthesis and storage.

The fed state, similar to the absorptive state, also focuses on lipid synthesis. However, the absorptive state is specifically where lipid metabolism is maximally increased due to high nutrient availability post-meal.