TDEE defined
Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period, accounting for all activities from breathing and organ function to exercise and daily movement. It is your caloric maintenance level — the number of calories you need to eat to keep your weight exactly the same.
Eat above your TDEE and you gain weight. Eat below it and you lose weight. This is the fundamental equation underpinning all nutrition strategies, regardless of the specific diet approach (keto, paleo, intermittent fasting, etc.).
The four components of TDEE
TDEE has four distinct components, each contributing a different proportion to total daily burn:
| Component | % of TDEE | Description |
|---|---|---|
| BMR | 60–70% | Calories burned at complete rest |
| NEAT | 15–20% | Daily movement outside exercise |
| TEF | ~10% | Digesting and processing food |
| EAT | 5–20% | Planned exercise sessions |
BMR — the largest component — is determined by body size, age, sex, and lean mass. NEAT varies enormously between individuals and is the most modifiable component through daily lifestyle choices.
How TDEE is calculated
TDEE is estimated by first calculating BMR using an equation (the Mifflin-St Jeor formula is the most validated), then multiplying by an activity factor to account for daily movement and exercise.
Mifflin-St Jeor (most accurate):
Men: (10 × kg) + (6.25 × cm) − (5 × age) + 5
Women: (10 × kg) + (6.25 × cm) − (5 × age) − 161
TDEE = BMR × Activity multiplier (1.2 to 1.9)
For example: a 30-year-old woman, 65 kg, 165 cm, lightly active: BMR = (10 × 65) + (6.25 × 165) − (5 × 30) − 161 = 1,450 kcal. TDEE = 1,450 × 1.375 = 1,994 kcal/day.
What affects your TDEE
Body size and lean mass: Larger people burn more calories. More muscle mass means a higher BMR since muscle is metabolically active tissue.
Age: BMR declines roughly 1–2% per decade from age 20, primarily due to natural muscle loss. This is why maintaining muscle through resistance training is so important for long-term metabolic health.
Activity level: The most variable component. An elite athlete can have a TDEE 2–3× higher than a sedentary individual of the same size.
Diet history: Prolonged calorie restriction reduces TDEE through adaptive thermogenesis — the body becomes more efficient. This is why diet breaks are important during extended weight loss phases.
How to use your TDEE
- Weight loss: Eat TDEE minus 300–500 kcal/day for a rate of ~0.3–0.5 kg/week
- Maintenance: Eat at TDEE to keep weight stable
- Muscle gain (lean bulk): Eat TDEE plus 200–300 kcal/day
- Recalculate every 6–8 weeks as weight and activity levels change