Comprehensive Guide to Understanding BMI

BMI stands for Body Mass Index. It's a numerical value of your weight in relation to your height. Used globally, it helps to categorize individuals into various weight status levels.

BMI is calculated by dividing a person’s weight in kilograms by the square of their height in meters. The formula is BMI = kg/m². It's a quick and non-invasive screening tool.

BMI ranges are standardized: under 18.5 is underweight, 18.5-24.9 is normal, 25-29.9 overweight, and over 30 is obese. Each range is associated with different health risks.

BMI doesn’t distinguish between muscle and fat. Athletes often fall into 'overweight' or 'obese' categories due to muscle mass. It's less accurate for the elderly, children, and some ethnic groups.

Waist circumference and body fat percentage are additional tools that provide a more complete picture of health. They can identify risks that BMI alone cannot, such as visceral fat.

In 1998, the USA redefined BMI categories, overnight turning 29 million Americans from 'normal' to 'overweight' without any change in their actual weight.