What is the Mifflin-St. Jeor equation?

• A. Males: ABW (kg) × 9.99 × Ht (cm) × 6.25 − Age (years) × 4.92 + 5
• B. Males: ABW (kg) × 9.99 + Ht (cm) × 6.25 − Age (years) × 4.92 + 5
• C. Females: ABW (kg) × 9.99 × Ht (cm) × 6.25 − Age (years) × 4.92 − 161
• D. Females: ABW (kg) × 9.99 × Ht (cm) × 6.25 − Age (years) × 4.92 + 161

Answer: (A)

The Mifflin-St. Jeor equation estimates resting metabolic rate (RMR) from body weight, height, age, and sex, using separate terms for each factor rather than multiplying them together. The standard forms are: for men, RMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5; for women, RMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161. This way, weight, height, and age each contribute additively with their respective multipliers, and a sex-specific constant is added or subtracted at the end.

The options shown mix weight and height in a single product and use slightly different numbers, which does not match the correct structure of the Mifflin-St. Jeor equation. The appropriate formula uses separate terms for weight and height, a subtraction of five times age, and a plus constant for men or a minus constant for women.