What is BMI?
Body Mass Index (BMI) is a numerical value calculated from your weight and height. It provides a simple way to categorize individuals as underweight, normal weight, overweight, or obese. The formula for BMI is:
BMI = weight (kg) / (height (m))²
For those using imperial measurements, the formula is slightly different:
BMI = (weight (lbs) / (height (in))²) × 703
BMI Categories
The World Health Organization defines the following BMI categories for adults:
| Category | BMI Range |
|---|---|
| Underweight | Below 18.5 |
| Normal weight | 18.5 - 24.9 |
| Overweight | 25 - 29.9 |
| Obesity | 30 and above |
Limitations of BMI
While BMI is a useful screening tool, it has several limitations:
- Doesn't directly measure body fat
- Doesn't account for muscle mass (athletes may be classified as overweight)
- Doesn't consider bone density or overall body composition
- May not be equally accurate across all ethnic groups
When to Use BMI
BMI is most useful as a general population screening tool. It can help identify potential weight problems that may lead to health issues. However, it should be used in conjunction with other assessments for a complete health picture.
If your BMI falls outside the normal range, consider consulting with a healthcare professional who can perform more comprehensive assessments.