Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A): Human most easily tolerates a lack of carbohydrate.
Reason (R): In human body carbohydrate provide energy of 9 Kcal/g

• A. Both (A) and (R) are true and (R) is the correct explation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

Remember the standard Atwater energy values for macronutrients: 1. Carbohydrates = \(4\text{ Kcal/g}\) 2. Proteins = \(4\text{ Kcal/g}\) 3. Fats = \(9\text{ Kcal/g}\)

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Evaluating the nutritiol role and energetic values of macronutrients (carbohydrates, proteins, and lipids) is essential in human nutrition and metabolism.
While the body requires energy to function, it can utilize different metabolic pathways to synthesize or substitute for certain nutrients during periods of dietary restriction.

Step 2: Detailed Explation:
Let us alyze both statements independently:
- Assertion (A): The human body can tolerate a lack of dietary carbohydrates better than a lack of essential amino acids (proteins) or essential fatty acids (lipids).
While some tissues like the brain and red blood cells rely on glucose for energy, the liver can synthesize glucose from non-carbohydrate precursors (like amino acids, glycerol, and lactate) via gluconeogenesis.
During prolonged carbohydrate restriction, the body can also adapt to utilize ketone bodies derived from fatty acid metabolism as an altertive energy source.
Because there are no "essential" carbohydrates that the body cannot synthesize itself, a dietary lack of carbohydrates is relatively well-tolerated.
Thus, Assertion (A) is true.
- Reason (R): The physiological energy value of macronutrients is as follows:
- Carbohydrates provide approximately \(4\text{ Kcal/g}\) of energy.
- Proteins provide approximately \(4\text{ Kcal/g}\) of energy.
- Fats (lipids) are the most energy-dense macronutrient, providing approximately \(9\text{ Kcal/g}\) of energy.
Therefore, the statement that carbohydrates provide \(9\text{ Kcal/g}\) is incorrect.
Thus, Reason (R) is false.

Step 3: Fil Answer:
The Assertion is true, but the Reason is false because carbohydrates provide \(4\text{ Kcal/g}\), not \(9\text{ Kcal/g}\).
Hence, the correct option is (C).