Understanding Body Mass Index (BMI)
Body Mass Index (BMI) is a simple screening tool used worldwide to categorize weight status. While not a perfect measure of health, it provides a useful starting point for understanding the relationship between your weight and height.
What is BMI?
BMI is a calculation that divides an adult's weight in kilograms by their height in meters squared. It was developed in the 19th century by Adolphe Quetelet to help quantify the amount of tissue mass (muscle, fat, and bone) in an individual.
BMI = weight (kg) / height² (m²)
BMI Categories
| BMI Range | Classification |
|---|---|
| < 18.5 | Underweight |
| 18.5 – 24.9 | Normal Weight |
| 25 – 29.9 | Overweight |
| ≥ 30 | Obesity |
It's Not the Whole Story
BMI is a screening tool, not a diagnostic of body fatness or health. It has some well-known limitations:
- Athletes: High muscle mass can result in a high BMI even with low body fat.
- Elderly: Older adults may have more body fat than younger adults with the same BMI.
- Pregnancy: BMI is not applicable during pregnancy.
Health Context
Always consult a healthcare provider for a complete assessment. They might use skinfold thickness measurements, evaluations of diet, physical activity, and family history. Learn more at the CDC website.