During prolonged fasting, in what sequence are the following organic compounds consumed by the body :-

Options

A. First carbohydrates, next fats and lastly proteins
B. First fats, next carbohydrates and lastly proteins
C. First carbohydrates, next proteins and lastly lipids
D. First proteins, next lipids and lastly carbohydrates

Answer

**Step-by-Step Solution:**

1. **Understanding the Body's Energy Needs During Fasting:**
- During prolonged fasting, the body requires energy to maintain its functions. It utilizes stored organic compounds in a specific order based on their availability and the ease of breakdown.

2. **First Source of Energy - Carbohydrates:**
- The first organic compound the body consumes is carbohydrates. Carbohydrates are readily available in the form of glycogen stored in the liver and muscles. They provide a quick source of energy, yielding approximately 4 kilocalories per gram.

3. **Second Source of Energy - Fats:**
- Once the carbohydrate stores are depleted, the body turns to fats (lipids) as the next source of energy. Fats provide a higher energy yield of about 9 kilocalories per gram but require more time for breakdown and are not as readily available as carbohydrates.

4. **Third Source of Energy - Proteins:**
- Finally, when both carbohydrates and fats are exhausted, the body resorts to using proteins for energy. Proteins yield about 4 kilocalories per gram, but their breakdown is complex and not efficient for immediate energy needs. The body prefers to use proteins for building and repairing tissues rather than as a primary energy source.

5. **Conclusion:**
- Therefore, the sequence in which the body consumes organic compounds during prolonged fasting is: **Carbohydrates → Fats → Proteins**. This corresponds to **Option 1**.

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