**Basal Metabolic Rate (BMR) – Simplified Explanation**

**What is BMR?**
BMR is the number of calories your body burns at complete rest to maintain basic life functions like breathing, circulation, and organ function. It’s like the energy needed to keep a parked car running.

**Key Facts:**
– BMR accounts for about 70% of your total daily calorie burn
– Physical activity: ~20% of daily calories
– Food digestion: ~10% of daily calories

**BMR Calculation Formulas:**
*Most Accurate Equations:*

1. **Mifflin-St Jeor Equation** (Most accurate for general population):
– Men: BMR = 10W + 6.25H – 5A + 5
– Women: BMR = 10W + 6.25H – 5A – 161

2. **Revised Harris-Benedict Equation:**
– Men: BMR = 13.397W + 4.799H – 5.677A + 88.362
– Women: BMR = 9.247W + 3.098H – 4.330A + 447.593

3. **Katch-McArdle Formula** (Best for lean individuals who know body fat %):
– BMR = 370 + 21.6(1 – F)W

*Where: W = weight (kg), H = height (cm), A = age, F = body fat %*

**Factors Affecting BMR:**
– **Muscle Mass:** More muscle = higher BMR
– **Age:** BMR decreases with age
– **Genetics:** Inherited traits influence metabolic rate
– **Weather:** Cold environments increase BMR
– **Diet:** Starvation lowers BMR; frequent meals may increase it
– **Pregnancy:** Increases BMR
– **Supplements:** Caffeine and some drugs can raise BMR

**Daily Calorie Needs:**
Multiply your BMR by an activity factor:
– Sedentary: BMR × 1.2
– Light activity: BMR × 1.375
– Moderate activity: BMR × 1.55
– Very active: BMR × 1.725
– Extremely active: BMR × 1.9

**Important Notes:**
– Online BMR calculators provide estimates only
– For precise measurement, consult a specialist or use calorimetry
– Individual BMR can vary by up to 26% due to unknown factors
– Use BMR as a starting point and adjust based on your actual results

BMR gives you a foundation for understanding your energy needs, but tracking your actual progress through diet and exercise journals is the most reliable approach to reaching your health goals.