What is BMI?
BMI is short for Body Mass Index and is a simple measure of your weight relative to your height. It's by no means a perfect measure but it's a useful starting point for understanding your weight.
The BMI scale splits people into four different ranges: underweight, normal weight, overweight and obese. Technically, there are several obese brackets but for simplicity we only use these four categories.
The normal range denotes a healthy weight while overweight and obese BMI suggests your weight may cause health risks.
Why does BMI matter?
Statistically, the higher your BMI, the greater risk you'll have of developing certain weight-related conditions, like:
- Type 2 diabetes
- Several types of cancer
- High blood pressure
- High cholesterol
- Sleep apnoea
By losing weight - or lowering your BMI - you may be able to reduce your risk of several or all of these health conditions.
BMI for women, men and different ethnicities
Our BMI scale does not differentiate on gender as women tend to be shorter but have more body fat, and men tend to be taller and have more muscle mass. As muscles weigh more than fat, these cancel each other out.
We do however adjust the BMI range according to ethnicity as people from different ethnic groups naturally have different body builds.
Who does BMI not work for?
For the majority of people, BMI is an adequate measure of body weight. Finding your BMI requires nothing more than a set of scales, a tape measure and a calculator. There are however some groups whose BMI results will be thrown off.
People with a lot of muscle mass or pregnant women, for example, tend to have a high BMI without being considered overweight. On the other side of the scale, some people may be in the normal range yet have a lot of body fat compared to muscle mass.
Age also matters for BMI as older people naturally have more body fat without this being as much of a problem in the lower end of the overweight range.
What other measures can I use?
Something as simple as waist circumference is a very useful tool for understanding whether you are overweight. For women, a waist circumference of 80 cm or more indicates a higher risk of developing weight related illnesses. For men, the number is 94 cm.
It is also possible to take a body fat scanner at a gym or a physiotherapist although this is a little more complicated and can be expensive.
