MCQ Detailed View

The calorific value of a nutrient refers to the amount of energy it provides to the body when it is completely oxidized during metabolism. Energy is measured in kilocalories (kcal) or kilojoules (kJ) and is essential for performing various bodily functions such as movement, growth, repair, and maintaining body temperature.Among the given nutrients, fats provide the maximum calorific value. On average:

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  Fats: ~9 kcal per gram

  
  


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  Carbohydrates: ~4 kcal per gram

  
  


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  Proteins: ~4 kcal per gram

  
  


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  Vitamins: 0 kcal (they do not supply energy directly)

  
  

Fats are energy-dense molecules because they contain long chains of carbon and hydrogen atoms. When these bonds are broken down during metabolism, they release a high amount of energy compared to carbohydrates and proteins. This is why the human body stores excess energy as fat, making it an efficient energy reserve for future use.

Carbohydrates are the body’s primary source of quick energy, but they provide less energy per gram than fats. Proteins, although capable of providing energy, are primarily used for building and repairing tissues rather than energy production. Vitamins, on the other hand, are micronutrients that do not provide energy; instead, they help in regulating metabolic processes.

Consuming fats is essential in moderation because they not only supply energy but also help in absorbing fat-soluble vitamins (A, D, E, K) and support cell membrane structure. However, excessive fat intake, especially saturated and trans fats, can lead to health issues such as obesity and heart disease.

In conclusion, fats have the highest calorific value compared to carbohydrates, proteins, and vitamins, making option B (Fats) the correct answer to this biology MCQ.