Body Composition Ratios: BMI, WHR, Body Fat %, WHtR, MMI, BVI

Body composition ratios quantify fat, muscle, and distribution for health risk assessment.

1. BMI (Body Mass Index)

Weight (kg) / Height (m)². Categories: <18.5 underweight, 18.5–24.9 normal, 25–29.9 overweight, ≥30 obese. Simple, population-level; limited by muscle mass, ethnicity.

2. WHR (Waist-to-Hip Ratio)

Waist (narrowest) / Hip (widest). >0.90 (M), >0.85 (F) = central obesity → higher cardiometabolic risk.

3. Body Fat % (%BF)

Fat mass / Total mass. Methods: DEXA (gold), BIA, skinfolds, ADP (Bod Pod), hydrostatic. Essential fat: M 2–5%, F 10–13%; Athletic: M 6–13%, F 14–20%; Obesity: M >25%, F >32%.

4. WHtR (Waist-to-Height Ratio)

Waist / Height. >0.5 = increased risk. Better than BMI for short/tall, ethnic variation.

5. MMI (Muscle Mass Index)

Lean mass (kg) / Height (m)². Low = sarcopenia risk. Complements BMI.

6. BVI (Body Volume Index)

3D scanning → volume, density, fat/lean distribution. Emerging, more accurate than BMI.

Integration

No single ratio suffices. Combine: BMI + WHR/WHtR + %BF + clinical context for personalized assessment.