Understanding the Core Components of TDEE
Your Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period, factoring in everything from resting functions to intense exercise. The complete formula is not a single, simple calculation but rather a combination of several factors.
The TDEE is comprised of four main elements:
- Basal Metabolic Rate (BMR): The calories your body burns at complete rest for vital functions, typically 60-75% of total expenditure.
- Thermic Effect of Food (TEF): Energy required to digest food, about 10% of daily expenditure.
- Exercise Activity Thermogenesis (EAT): Calories burned during planned exercise.
- Non-Exercise Activity Thermogenesis (NEAT): Energy expended for daily movements outside of structured exercise.
Calculating Your BMR: Mifflin-St Jeor and Harris-Benedict
Two primary equations are used to calculate BMR. The Mifflin-St Jeor equation is considered more accurate for modern individuals and is widely used today. The older Harris-Benedict equation, while still used, can sometimes overestimate caloric needs.
Mifflin-St Jeor BMR Formulas:
- For Men: $(10 ext{weight in kg}) + (6.25 ext{height in cm}) - (5 * ext{age in years}) + 5$
- For Women: $(10 ext{weight in kg}) + (6.25 ext{height in cm}) - (5 * ext{age in years}) - 161$
Harris-Benedict BMR Formulas:
- For Men: $66.5 + (13.75 ext{weight in kg}) + (5.003 ext{height in cm}) - (6.75 * ext{age in years})$
- For Women: $655.1 + (9.563 ext{weight in kg}) + (1.850 ext{height in cm}) - (4.676 * ext{age in years})$
To see an example calculation using the Mifflin-St Jeor formula, please refer to the referenced document.
The Activity Multiplier: Converting BMR to TDEE
To convert your BMR into TDEE, you apply an activity multiplier that reflects your lifestyle and exercise habits.
TDEE Activity Multipliers:
- Sedentary (little to no exercise): BMR x 1.2
- Lightly Active (light exercise 1-3 days/week): BMR x 1.375
- Moderately Active (moderate exercise 3-5 days/week): BMR x 1.55
- Very Active (hard exercise 6-7 days/week): BMR x 1.725
- Extra Active (very intense daily exercise): BMR x 1.9
Your calculated TDEE is a benchmark for setting dietary goals. You can maintain weight by consuming close to your TDEE, lose weight with a calorie deficit, or gain weight with a calorie surplus. A deficit of 500 calories per day typically leads to about one pound of weight loss per week. Remember that these formulas provide estimates, and individual results can vary due to factors like genetics and body composition. Adjusting your intake based on your body's response is key.
Mifflin-St Jeor vs. Harris-Benedict Comparison
| Feature | Mifflin-St Jeor Equation | Harris-Benedict Equation |
|---|---|---|
| Introduction Year | 1990 | 1919 (revised 1984) |
| Accuracy | Generally considered more accurate | Less accurate than Mifflin-St Jeor, can overestimate needs |
| Primary Use | Estimating BMR for TDEE calculation | Traditional BMR estimation |
| Required Variables | Age, gender, weight, height | Age, gender, weight, height |
| Body Fat Needed? | No | No |
Conclusion
To determine what is the formula for TDEE, you first calculate your BMR using an equation like Mifflin-St Jeor and then apply an activity multiplier. This provides an estimated daily calorie burn, which is a valuable starting point for managing weight. Tracking your progress and making adjustments based on your results are essential for achieving your health and fitness objectives.
Authoritative Link
- For more detailed information on TDEE, BMR, and related nutrition topics, visit the National Academy of Sports Medicine: Calorie Intake and Weight Loss Calculator - NASM Bodyweight Tool
