Work out your basal metabolic rate (the calories your body burns at rest) and your total daily energy expenditure at five activity levels, so you know roughly how many calories keep your weight stable.
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BMR vs TDEE
- BMR is the energy your body uses just to stay alive at rest: breathing, circulation, keeping warm.
- TDEE adds everything else: walking, work, exercise and digesting food. It’s BMR multiplied by an activity factor.
Eating at your TDEE should keep your weight roughly steady. Eating less leads to weight loss, and more to weight gain.
Worked example
A 35-year-old man, 178 cm and 80 kg, has a BMR of about 1,743 kcal. With moderate exercise 3 to 5 days a week his TDEE is about 2,700 kcal. To lose about 0.5 kg a week, he might aim for around 2,200 kcal.
Activity factors
| Level | Multiply BMR by |
|---|---|
| Mostly sitting | 1.2 |
| Light exercise 1–3 days | 1.375 |
| Moderate exercise 3–5 days | 1.55 |
| Hard exercise 6–7 days | 1.725 |
| Very hard or physical job | 1.9 |
Most people overestimate their activity. If unsure, pick the lower level and adjust after a few weeks of tracking your weight.
Frequently asked questions
What is a normal BMR?
It varies with size, age and sex, but many adults fall between about 1,200 and 2,000 kcal a day.
Which formula is most accurate?
Mifflin-St Jeor is widely regarded as one of the most accurate for most adults, typically within about 10%.
Should I eat below my BMR to lose weight?
Not usually. A modest deficit from your TDEE is more sustainable and safer. Very low-calorie diets should only be done with medical supervision.
Does muscle increase BMR?
Yes, a little. Muscle uses more energy than fat at rest, which is one reason strength training helps.
Sources
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