Energy Expenditure and Intake Relationship
Understanding Energy Balance
The relationship between energy expenditure and intake is like a metabolic seesaw that determines our body weight and composition. Let's break this down into digestible pieces!
Energy Balance Equation
$\text{Energy Balance} = \text{Energy Input} - \text{Energy Output}$
- Positive Balance (weight gain): When intake exceeds expenditure
- Negative Balance (weight loss): When expenditure exceeds intake
- Equilibrium (weight maintenance): When intake equals expenditure
1 pound of body fat contains approximately 3,500 calories of energy. This means to lose 1 pound of fat, you need to create a deficit of 3,500 calories.
Components of Energy Expenditure
1. Basal Metabolic Rate (BMR)
- Accounts for 60-75% of daily energy expenditure
- Energy needed for basic life functions
- Influenced by:
- Body size and composition
- Age
- Gender
- Hormonal status
2. Thermic Effect of Food (TEF)
- Represents 10% of daily energy expenditure
- Energy used to digest, absorb, and process nutrients
- Varies by macronutrient:
- Protein: 20-30% of calories consumed
- Carbohydrates: 5-10%
- Fats: 0-3%
3. Physical Activity
- Most variable component
- Includes:
- Planned exercise
- Non-exercise activity thermogenesis (NEAT)
- Sports and training
Athletes need to pay special attention to matching their energy intake with their expenditure, as inadequate intake can impair performance and recovery.
