Understanding BMR vs. TDEE
Managing weight effectively requires understanding how your body expends energy every day:
- Basal Metabolic Rate (BMR): The minimum number of calories your body burns at complete rest just to perform basic life-sustaining functions like breathing, circulation, and cell production.
- Total Daily Energy Expenditure (TDEE): The total number of calories you burn in a 24-hour period, combining your BMR with physical activity, workouts, digestion, and daily movements.
The Mifflin-St Jeor BMR Formula
This calculator utilizes the Mifflin-St Jeor equation, widely recognized by clinical dietitians as one of the most accurate BMR estimation formulas:
Men: BMR = (10 ร weight in kg) + (6.25 ร height in cm) - (5 ร age in yrs) + 5
Women: BMR = (10 ร weight in kg) + (6.25 ร height in cm) - (5 ร age in yrs) - 161
Worked example: 28-year-old male, 75 kg, 178 cm height, moderately active (activity multiplier 1.55):
BMR = (10 ร 75) + (6.25 ร 178) - (5 ร 28) + 5 = 1,727.5 kcal/day
TDEE = 1,727.5 ร 1.55 = 2,678 kcal/day (Maintenance)
Calorie Goals for Weight Loss & Gain
- Weight Maintenance: Eat equal to your TDEE daily.
- Moderate Fat Loss (-0.5 kg/wk): Consume TDEE minus 500 calories per day.
- Muscle Gain (+0.25 kg/wk): Consume TDEE plus 250โ300 calories per day combined with resistance training.
Frequently Asked Questions
Is TDEE the same every day?
No. TDEE varies depending on daily steps, workout intensity, non-exercise activity (NEAT), and sleep quality. Using weekly average calorie intake helps smooth out daily activity variances.
Why shouldn't I drop calories too low?
Severely restricting calories far below your BMR can trigger adaptive thermogenesis (metabolic slowdown), cause muscle loss, fatigue, and hormonal imbalances.