BMI Explained: What the Number Really Means
BMI is a useful screening tool — not a diagnosis. Here's what it tells you and what it misses.
Body Mass Index (BMI) is weight in kilograms divided by height in meters squared. It's the most widely used population-level measure of body composition.
Standard categories
Under 18.5 is underweight, 18.5–24.9 is normal, 25–29.9 is overweight, and 30+ is obese. These thresholds come from large epidemiological studies linking BMI to mortality risk.
Where BMI falls short
BMI doesn't distinguish muscle from fat, so athletes often score 'overweight'. It also doesn't account for fat distribution — visceral fat is far more dangerous than subcutaneous fat. Pair BMI with waist circumference and body-fat percentage for a clearer picture.
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