What is BMI?
The Body Mass Index (BMI) is a screening method approved by the World Health Organization (WHO) to categorize body weight. It estimates body fat based on your height and weight ratio.
Knowing your BMI helps in assessing potential health risks. High BMI is often linked to chronic conditions like type 2 diabetes, hypertension, and cardiovascular diseases.
Why Calculate BMI?
- Simple screening for weight categories
- Helps doctors determine metabolic risk
- Useful baseline for fitness goals
BMI Categories & Health Risk (Adults)
| Classification | BMI Range (kg/m²) | Health Risk Level |
|---|---|---|
| Underweight | < 18.5 | Moderate |
| Normal Weight | 18.5 – 24.9 | Low Risk (Optimal) |
| Overweight | 25.0 – 29.9 | Increased Risk |
| Obese | 30.0 + | High Risk |
BMI Formula
The calculation is simple but depends on your unit system.
Metric System
BMI = Weight (kg) ÷ Height (m)²Imperial System
BMI = 703 × Weight (lbs) ÷ Height (in)²Limitations
- Athletes: High muscle mass can falsely indicate obesity.
- Elderly: Muscle loss may hide high body fat.
Frequently Asked Questions
What is the best BMI for my age?
For most adults (18-65), a BMI between 18.5 and 24.9 is considered healthy. However, older adults (65+) may benefit from a slightly higher BMI (25-27) to protect against frailty and bone loss.
Is BMI accurate for athletes?
No. BMI does not distinguish between muscle and fat. Athletes with high muscle mass may be classified as 'Overweight' despite having low body fat. In such cases, Body Fat Percentage is a better metric.
What is the formula to calculate BMI?
Metric Formula: BMI = weight (kg) / [height (m)]². Imperial Formula: BMI = 703 × weight (lbs) / [height (in)]².
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