Official World Health Organization (WHO) adult weight classifications, BMI Prime indices, Asian population guidelines, and health risk stratifications.
1. International WHO Body Mass Index Classification
WHO Category
BMI Range (kg/m²)
BMI Prime
Health Risk Tier
Severe Thinness
< 16.0
< 0.64
Very High (Underweight Risk)
Moderate Thinness
16.0 – 16.9
0.64 – 0.67
Increased Nutritional Risk
Mild Thinness
17.0 – 18.4
0.68 – 0.73
Low to Mild Risk
Normal Weight
18.5 – 24.9
0.74 – 0.99
Lowest Health Risk
Overweight (Pre-obese)
25.0 – 29.9
1.00 – 1.19
Increased Risk (CVD / Diabetes)
Obese Class I (Moderate)
30.0 – 34.9
1.20 – 1.39
High Cardiovascular Risk
Obese Class II (Severe)
35.0 – 39.9
1.40 – 1.59
Very High Clinical Risk
Obese Class III (Morbid)
≥ 40.0
≥ 1.60
Extremely High Risk
2. WHO Asian Population Specific Cutoffs
In 2004, the WHO Expert Consultation recognized that populations of Asian descent exhibit higher percentages of body fat and elevated risks of type 2 diabetes and cardiovascular disease at lower BMI thresholds than non-Asian populations.
Asian BMI Category
BMI Range (kg/m²)
Public Health Action Point
Comorbidity Risk
Underweight
< 18.5
Nutritional Assessment
Increased Risk
Increasing Risk (Normal)
18.5 – 22.9
Maintain Healthy Weight
Low Risk
Overweight (Increased Risk)
23.0 – 27.4
Lifestyle / Dietary Intervention
Moderate Risk
Obese (High Risk)
≥ 27.5
Clinical Weight Management
High Risk
3. Caloric Deficit & Macronutrient Distribution Guidelines