Basal Metabolic Rate (BMR)
The total number of calories that your body needs to perform basic, life-sustaining functions at rest.
Basal Metabolic Rate (BMR) is the foundation of human energy expenditure. It represents the absolute minimum number of calories your body requires to keep you alive while you are completely at rest (breathing, circulating blood, cellular growth, and neurological function).
Your BMR typically accounts for 60% to 75% of your total daily energy expenditure.
The Mathematics of BMR
The most widely used mathematical formula for calculating BMR is the Mifflin-St Jeor Equation, which has been shown to be highly accurate for modern populations:
- For Men:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5 - For Women:
BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161
Why it Matters
Understanding your BMR is the mathematical starting point for any weight loss or muscle gain journey. To lose weight, you must consume fewer calories than your Total Daily Energy Expenditure (which is your BMR multiplied by an activity factor). To gain mass, you must consume more. Attempting to manage weight without knowing your approximate BMR is equivalent to managing a budget without knowing your base salary.