During rest,metabolic requirement are minimum.This is indicate by

Answer

To solve the question regarding metabolic requirements during rest, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Metabolic Requirements**:
- At rest, the body has minimal metabolic requirements. This means that the energy sources utilized by the body will be those that are most readily available and efficient.

2. **Identifying Energy Sources**:
- The primary energy sources for the body are carbohydrates, fats, and proteins. Each of these macronutrients contributes to energy production, but they do so in a specific order based on availability and efficiency.

3. **Energy Utilization Order**:
- **Carbohydrates**: When at rest, the body first utilizes carbohydrates as they provide the quickest and most efficient source of energy. Carbohydrates are broken down into glucose, which is then used to produce ATP (adenosine triphosphate), the energy currency of the cell.
- **Fats**: Once carbohydrates are depleted, the body will turn to fats for energy. Fats are broken down into fatty acids and glycerol, which can also be converted into ATP, but this process is slower compared to carbohydrates.
- **Proteins**: Proteins are the least preferred source of energy. They are only utilized when carbohydrates and fats are insufficient. The breakdown of proteins into amino acids for energy production occurs last.

4. **Conclusion**:
- Therefore, the correct order of energy utilization during rest is: first carbohydrates are used up, followed by fats, and finally proteins. This aligns with the body's metabolic strategy to conserve proteins for essential functions rather than using them as a primary energy source.

### Final Answer:
The correct answer is: **First carbohydrates are used up, followed by fats and proteins towards the end.**

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