You may have heard the term BMI when reading about health and weight management, but what does it actually mean? Our friends at Hillmotts know a thing or two about weight loss, so they are here to set the record straight and help you understand how it all works.
Body Mass Index (BMI) is a number calculated from a person's weight and height and can be a good indicator of body fat. However, it is a broad measure only and is not totally applicable for everyone. For instance, athletes tend to have a very high BMI but this is due to their muscle density, rather than fat.
BMI can be considered an alternative for direct measures of body fat and is an inexpensive and easy-to-perform method of screening for weight categories that may lead to health problems.
So why do people use it?
BMI is an attractive measure because it is an easy, cheap and non-invasive means of assessing excess body fat. True measures of body fat are impractical or expensive to use at a large scale (such as across populations), so it’s really useful as a ‘one size fits all’ way of getting an idea of how healthy people are.
BMI is widely used around the world and has been measured for some time, enabling comparisons between areas, across population sub-groups and over time. Another advantage of BMI as a practical measure of obesity is the availability of published thresholds and growth references to which children’s BMI can be compared. BMI in children varies with age and sex, which prevents the use of fixed thresholds as in adults. Equivalent growth references do not exist for other measures such as waist circumference.
Want to know your BMI?
It’s very simple to calculate your own BMI because only two factors are required, your height and your weight. Have a go and see how you measure up! Here’s what you need to do:
- Divide your weight in kilograms (kg) by your height in metres (m)
- Then divide the answer by your height again to get your BMI
- If you weigh 70kg and you're 1.75m tall, divide 70 by 1.75. The answer is 40.
- Then divide 40 by 1.75. The answer is 22.9. This is your BMI.
On the BMI scale, anything below 18.5 is considered "underweight," 18.5 to 24.9 is "normal," 25.0 to 29.9 is "overweight" and an index of 30 or more is "obese."
If your BMI is a little higher than you might like, or you want to get in better shape for the summer, why not have some fun while you do it and read our article on getting fit the fun way !