About BMR Calculator
Your Basal Metabolic Rate (BMR) is the number of calories your body burns performing basic life-sustaining functions like breathing, circulation, and cell production. It accounts for about 60-75% of your total daily calorie burn, making it the most significant component of your metabolism.
Scientific Basis
We use the Mifflin-St Jeor equation, which was introduced in 1990. Systematic reviews have shown it to be more accurate than the older Harris-Benedict equation for modern populations. It estimates energy expenditure based on weight, height, age, and biological sex.
Health Implications
Understanding your BMR is crucial for weight management:
- Undereating: consistently eating below your BMR can trigger 'adaptive thermogenesis' (metabolic slowdown), causing your body to conserve energy and making weight loss harder long-term.
- Aging: BMR naturally declines by about 1-2% per decade after age 20, primarily due to muscle loss.
Actionable Tips
Build Muscle: Muscle tissue burns about 6x more calories at rest than fat tissue.
Eat Protein: The Thermic Effect of Food (TEF) is highest for protein, temporarily boosting metabolism.
Don't Starve: Avoid crash diets that drop calories too low, as they can permanently lower your BMR.
Limitations
The calculator provides an estimate. Individual factors like genetics, thyroid health (hypothyroidism), and body composition (muscle vs. fat) can cause your actual BMR to vary by 10-15%.