Question

The energy values (kcal/g) available from nutrients, protein and lipid are ?

• A. 4 and 5
• B. 5 and 4
• C. 5 and 9
• D. 9 and 4

Hint:

Remember the standard gross energy values: Lipids are highly energy-dense ($9.4 \text{ kcal/g}$, rounded to 9), while proteins yield approximately $5.6 \text{ kcal/g}$ (rounded to 5).

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Energy values of food nutrients are evaluated as gross energy (the total heat released during complete combustion in a bomb calorimeter) or as physiological fuel values (the actual energy available to the organism after digestion and excretion).
Detailed Explanation:
In general nutrition and biochemistry, the energy values of macronutrients are defined as:
- Proteins: The gross energy of protein is approximately $5.65 \text{ kcal/g}$ (frequently rounded to $5 \text{ kcal/g}$ in basic nutritional formulations).
Because fish do not completely oxidize nitrogenous compounds and excrete ammonia rather than urea, their digestible energy value for protein is closer to $4.5 \text{ kcal/g}$.
- Lipids: The gross energy of lipids is approximately $9.4 \text{ kcal/g}$ (regularly rounded to $9 \text{ kcal/g}$).
- Carbohydrates: The gross energy of carbohydrates is approximately $4.1 \text{ kcal/g}$ (rounded to $4 \text{ kcal/g}$).
Looking at the options, the pair that represents the energy values for protein and lipid is 5 and 9.

Step 2: Final Answer:
The energy values (kcal/g) for protein and lipid are 5 and 9, respectively, corresponding to option (3).