Your basal metabolic rate (BMR) is the energy your body burns at rest to sustain vital functions: breathing, blood circulation, and temperature regulation. BMR accounts for 60–75% of your total daily energy expenditure.
The Mifflin-St Jeor Formula
The most accurate formula validated by modern clinical studies:
- Male: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
- Female: BMR = (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161
Example: 75 kg male, 175 cm, 30 years old → BMR = 750 + 1,094 − 150 + 5 = 1,699 kcal/day
From BMR to TDEE: Your Total Daily Calorie Needs
| Activity level | Multiplier | Profile |
|---|---|---|
| Sedentary | × 1.2 | Desk job, little exercise |
| Lightly active | × 1.375 | Light exercise 1–3×/week |
| Moderately active | × 1.55 | Moderate exercise 3–5×/week |
| Very active | × 1.725 | Hard exercise 6–7×/week |
| Athlete | × 1.9 | Twice-daily training or physical job |
Matching Calories to Your Goal
- Weight loss: TDEE − 400–500 kcal → ~0.5 kg/week loss
- Maintenance: Eat exactly your TDEE
- Muscle gain: TDEE + 250–300 kcal (lean bulk)
⚠️ Never go below 1,200 kcal/day (women) or 1,500 kcal/day (men) without medical supervision.
What Affects Your BMR
- Age: Drops ~2% per decade after age 30
- Muscle mass: Each extra kg of muscle burns ~13 extra kcal/day
- Thyroid function: Hypothyroidism can lower BMR by 15–40%
- Genetics: Explains up to 40% of variation between individuals
Conclusion
Knowing your BMR and TDEE gives you a scientific foundation for your nutrition plan. These are estimates — adjust your intake based on real results over 2–4 weeks. Nutrya automatically calculates your TDEE and personalizes your daily calorie goals.
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