What is TDEE?
TDEE (Total Daily Energy Expenditure) is the total number of calories your body burns in a day — resting metabolism, digestion, daily movement and exercise combined. It's the single most useful number for managing weight: eat below it to lose, above it to gain, at it to maintain.
The three formulas compared
- Mifflin-St Jeor (recommended): 10×kg + 6.25×cm − 5×age (+5 men / −161 women). The most accurate for the general population — used by dietitians.
- Revised Harris-Benedict: the 1984 revision of the classic 1919 formula. Slightly higher estimates for many people.
- Katch-McArdle: 370 + 21.6 × lean mass (kg). The most accurate if you know your body fat %, because muscle — not total weight — drives metabolism.
How to use your TDEE
- Lose fat: eat 10–20% below TDEE (see the goal table above)
- Build muscle: eat 5–15% above TDEE while strength training
- Maintain: eat at TDEE, watch the scale for 2–3 weeks, adjust ±100–150
What are macros?
"Macros" are the three macronutrients that make up your calories: protein (4 cal/g), carbs (4 cal/g) and fat (9 cal/g). Enough protein — roughly 1.6–2.2 g per kg of body weight — is the key to keeping muscle while losing fat.
Which formula should I trust?
Mifflin-St Jeor unless you know your body fat % — then Katch-McArdle. All formulas are starting estimates; real-world weight change over 2–3 weeks is the truth.
Why do the formulas disagree?
They were built on different study populations. The spread between them (usually 50–150 calories) is a good reminder that every number here is an estimate to refine, not a law.
Does TDEE change as I lose weight?
Yes — a lighter body burns fewer calories. Recalculate every 4–5 kg to keep your plan accurate.