Tuesday, 17 February 2015

Why using BMI on its own isn't the best idea

BMI - Body Mass Index - this is a number which is based on your height in relation to your weight. It is a fundamentally flawed method for determining if you're overweight or not. See this illustration below:


In this example, both these people have the exact same Body Mass Index. But clearly one is much better off than the other. The thing is, muscle weighs more than fat. And fat takes up much more space than muscle.

Out of interest, here's the formula for working out your BMI - but please don't use it as your only way of determining your health level:

Firstly, make sure you have your height and weight in meters and kilograms. For example, let's say you weight 70kg and you're 1.65m tall - so, divide your weight by your height, which in this example gives us 42.42 - now, divide this number once again by your height, which is 25.7 - this is your BMI.

But, and I want to reemphasize this again - do NOT use BMI as your only means of measuring your physique. Muscle and fat are very different!

A better way to determine your body composition is by weighing yourself on a Tanita Body Composition monitor or something similar. Those usually give you individual readings for at least Body Fat Percentage and Muscle Mass.