Definition of Overweight on the BMI Table
Overweight is defined as a Body Mass Index (BMI) of 25.0 to 29.9 kg/m² for adults in standard populations. 1, 2
Standard BMI Classification
The established BMI categories for adults are: 1, 2
- Underweight: BMI < 18.5 kg/m²
- Normal/Healthy Weight: BMI 18.5-24.9 kg/m²
- Overweight: BMI 25.0-29.9 kg/m²
- Obese: BMI ≥ 30.0 kg/m²
BMI Calculation Method
BMI is calculated using one of two formulas: 1
- Metric: Weight (kg) ÷ [Height (m)]²
- Imperial: [Weight (pounds) ÷ Height (inches)²] × 703
Important Ethnic Considerations
For Asian populations, lower BMI thresholds apply due to higher body fat percentages and visceral adiposity at lower BMI values. 2, 3
This adjustment reflects that Asian individuals have approximately 2-3 kg/m² lower BMI than Caucasians for the same body fat percentage and face higher cardiometabolic risks at lower BMI levels. 3
Clinical Significance of Overweight Category
Being overweight (BMI 25.0-29.9 kg/m²) carries increased health risks compared to normal weight, including: 1, 4
- Elevated risk for cardiovascular disease 4
- Increased cancer risk (particularly postmenopausal breast, colon, and other cancers) 1
- Higher rates of type 2 diabetes and stroke 1
Additional Assessment Beyond BMI
Waist circumference should be measured alongside BMI for complete risk assessment. 1, 2
High-risk thresholds are: 1
- Men: Waist circumference > 102 cm (> 40 inches)
- Women: Waist circumference > 88 cm (> 35 inches)
- Asian Women: Waist circumference ≥ 80 cm 3
Central adiposity increases cardiovascular and metabolic disease risk independent of overall BMI. 1, 2
Key Limitations
BMI does not distinguish between lean muscle mass and fat mass, potentially misclassifying muscular individuals as overweight. 2 However, BMI remains the most practical screening tool for routine clinical use, as direct body fat measurement methods are impractical for everyday practice. 1, 5