BMR and TDEE, in plain words
- BMR (basal metabolic rate): what your body burns to stay alive at rest: breathing, heart, brain, temperature. About 60 to 70% of your day.
- TDEE (total daily energy expenditure): your BMR plus digestion and every movement, from walking to the gym. It is your maintenance number.
- To lose weight, eat a little under your TDEE, never under your BMR for long.
The formulas
| Formula | Women | Men |
|---|---|---|
| Mifflin-St Jeor (1990) | 10 × kg + 6.25 × cm − 5 × age − 161 | 10 × kg + 6.25 × cm − 5 × age + 5 |
| Harris-Benedict, revised (1984) | 447.6 + 9.25 × kg + 3.10 × cm − 4.33 × age | 88.4 + 13.40 × kg + 4.80 × cm − 5.68 × age |
In a review of predictive equations, Mifflin-St Jeor came within 10% of measured resting energy in more people than the others, which is why dietitians and Enough use it. Harris-Benedict tends to give a little more.
Activity multipliers
| Level | Multiplier | Looks like |
|---|---|---|
| Mostly seated | 1.2 | Desk job, little exercise |
| Lightly active | 1.375 | Walks, light exercise 1 to 3 days a week |
| Active | 1.55 | Exercise 3 to 5 days a week |
| Very active | 1.725 | Hard exercise 6 to 7 days a week |
| Athlete | 1.9 | Training twice a day or a physical job |
Can you raise your metabolism?
A little. Muscle burns more than fat at rest, so strength training and enough protein help keep your BMR up while you lose weight. Daily steps raise your TDEE more than any "metabolism booster". Very low calorie diets do the opposite: the body saves energy and you move less without noticing.
Next: split your calories with the macro calculator, or see when you could reach your goal with the weight loss calculator.
Questions about BMR
What is a normal BMR?
For most adult women about 1,200 to 1,500 kcal a day, for most adult men about 1,500 to 1,900 kcal. It depends mainly on body size, then age and sex.
What is the difference between BMR and TDEE?
BMR is what you burn at complete rest. TDEE adds digestion and all your movement: it is your BMR multiplied by an activity factor from 1.2 to 1.9.
Should I eat my BMR to lose weight?
No need to go that low. Eating a little under your TDEE, about 250 to 750 kcal, is enough to lose weight and easier to keep.
Does BMR drop when you lose weight?
Yes, a lighter body needs less energy, and long diets lower it a bit more. That is why your line should be recalculated as you lose.
Sources
- Mifflin MD, St Jeor ST, et al. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 1990.
- Roza AM, Shizgal HM. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. American Journal of Clinical Nutrition, 1984.
- Frankenfield D, et al. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association, 2005.
This calculator gives general estimates, not medical advice. Thyroid conditions, some medications and pregnancy change energy needs: ask your doctor.