Basal Metabolic Rate

Definition

The basal metabolic rate (BMR) is the minimum energy expended by the body at complete rest to maintain vital functions: breathing, circulation, thermoregulation.

How it works

BMR represents 60-70% of total energy expenditure. It is estimated using the Harris-Benedict or Mifflin-St Jeor formulas. Muscle mass increases BMR (muscle consumes 13 kcal/kg/day vs 4 for fat). It decreases with age and during overly restrictive diets.

Role

Define the energy floor for caloric needs calculations.

Examples

• Man 70kg, 175cm, 30 years: BMR ≈ 1750 kcal
• Woman 60kg, 165cm, 30 years: BMR ≈ 1450 kcal

Recommendations

Never go below BMR during a diet — this causes muscle loss and yo-yo effect.

Key takeaway

Knowing your BMR is the first step to serious nutrition management.

Related terms