
Find a weight management provider near you
Weight management providers are specially trained to help people manage weight. Find weight management providers near you for a personalised plan to treat obesity.
For more than 150 years, the Body Mass Index (BMI) tool has been used to estimate how much body fat someone has to understand whether they are a healthy weight for their height. While it is a quick, easy-to-use, and popular measure, it can also be misleading in certain cases and for some groups of people.
The image is a model
In this article, we explore how these shortcomings of BMI can be outweighed by the valuable insights it provides for doctors and health experts to be able to define and diagnose obesity objectively, and to check and keep track of obesity rates in a country.
BMI is a simple mathematical formula using a person’s weight compared to their height. It is calculated as your weight (in kilograms) divided by the square of your height (in metres) or BMI = Kg/M2.
For example, if you weigh 70kg (approximately 11 stone) and are 1.73m (approximately 5 feet 8 inches) tall, you work out your BMI by:
- Squaring your height: (1.73 x 1.73) = 2.99
- Dividing your weight (70) by this number: 70/2.99 = 23.4
BMI = 23.4
The result of this calculation is a number that can be used to categorise individuals into different weight classifications, ranging from underweight or normal weight to overweight and various levels of obesity. If you want to calculate your BMI, you can use our handy BMI calculator.
While the BMI tool has been widely adopted across the world for many years, it’s not perfect. There have been calls to move away from the tool due to the following criticisms:
Despite its downsides in certain groups of people, BMI is generally an important and beneficial measure of a person’s level of body fat, and it continues to be used globally for the following reasons:
BMI continues to be a valuable and cost-effective tool that is easily accessed and used by doctors and individuals. While it has served as a useful measure to understand obesity at a population level for many years, it's important to remember that obesity is a complex disease. Every individual's journey with weight is unique. The most comprehensive way to understand and manage obesity and your individual circumstances is to have open conversations with healthcare professionals.
HQ23OB00401