What is TDEE?
TDEE stands for total daily energy expenditure: every calorie your body uses in 24 hours. It has three parts. Your basal metabolic rate (BMR) is the largest, usually 60 to 70% of the total. Physical activity, from walking to the office to a gym session, is the most variable. The thermic effect of food, the energy spent digesting, adds roughly another 10%.
Calculators estimate BMR from your sex, age, height and weight, then multiply it by an activity factor.
The two equations
- Mifflin-St Jeor (1990): 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5 for men, or - 161 for women.
- Revised Harris-Benedict (1984): 88.362 + 13.397 x weight + 4.799 x height - 5.677 x age for men; 447.593 + 9.247 x weight + 3.098 x height - 4.330 x age for women. The Calo AI app uses this one.
For a 30 year old man, 175 cm and 75 kg, Mifflin-St Jeor gives a BMR of about 1,699 kcal and Harris-Benedict about 1,763 kcal. At "lightly active" (x 1.375) that is a TDEE of about 2,336 or 2,424 kcal. The difference is small next to the uncertainty in any estimate.
Choosing your activity level
| Level | Multiplier | What it looks like |
|---|---|---|
| Sedentary | x 1.2 | Desk job, little or no exercise |
| Lightly active | x 1.375 | Exercise 1 to 3 days a week |
| Moderately active | x 1.55 | Exercise 3 to 5 days a week |
| Very active | x 1.725 | Hard exercise 6 to 7 days a week |
| Extra active | x 1.9 | Physical job plus daily training |
Most people overestimate their activity. If you have a desk job and work out three times a week, "lightly active" is usually closer than "moderately active". When in doubt, pick the lower level and adjust after a few weeks of real data.
How to use your TDEE
- Maintain: eat around your TDEE.
- Lose fat: eat 250 to 750 kcal below it. Use the calorie deficit calculator.
- Gain muscle: eat 150 to 500 kcal above it, with enough protein (see the protein calculator).