Question

In the 24 hour daily energy expenditure, the major contribution is by:

• A. Thermogenic Effect of food
• B. Energy used for exercise and physical activity
• C. Basal metabolic rate
• D. Energy used for non exercise activity

Hint:

Energy breakdown: - BMR ≈ 60–70% (largest) - Activity ≈ 20–30% - TEF ≈ 10%

Answer 1

The Correct Option is C

Concept:
Total daily energy expenditure (TDEE) consists of three main components:
• Basal Metabolic Rate (BMR) → Energy used at rest for vital functions
• Thermic Effect of Food (TEF) → Energy used in digestion
• Physical Activity Energy Expenditure → Exercise + non-exercise activities

Step 1: Understanding Basal Metabolic Rate.
BMR is the energy required to maintain essential body functions such as:
• Breathing
• Circulation
• Cell metabolism
• Temperature regulation It accounts for approximately: \[ 60\% \text{ to } 70\% \text{ of total daily energy expenditure} \]

Step 2: Understanding other components.

• Thermic Effect of Food → about 10%
• Physical Activity → varies (20–30%), but usually less than BMR unless highly active

Step 3: Comparing contributions.
Clearly: \[ \text{BMR} > \text{Physical Activity} > \text{TEF} \]

Step 4: Conclusion.
Since BMR contributes the largest portion of daily energy expenditure, the correct answer is: \[ \boxed{\text{Basal metabolic rate}} \]