BMI is one of the most popular tools that people use to determine whether they are in a healthy weight range. Because body fat and lean muscle tissue don't figure into the equation at all, many experts believe that BMI is not at all accurate for some people. In this article we will take a look at exactly what BMI is and why it isn't always accurate for some people.
BMI is short for Body Mass Index and was created by Adolphe Quetelt in the early 1800s. Basically, BMI compares a persons weight to their height and with this information will determine whether they are in the correct weight range for their height. BMI measurement has remained popular for all these years and still remains one of the most popular weight measurements.
Body fat, bone and frame size, muscle and body type are not included in the formula for working out BMI. The formula for working out BMI is to take your height in meters squared and divide your weight in kilograms by that number. Let's do an example: If you are 1.7 meters tall you would do 1.7 times 1.7 which equals 2.89. If you weigh 65 kilograms you would divide 65 by 2.89 which equals 22.49 as your BMI. This is in the normal weight range which is from 18.5 to 24.9. If you have a BMI below 18.5 then you are considered underweight and if you are over 24.9 then you are considered overweight. If your BMI is over 30 then you are considered obese.
Generally you can get an idea of whether you are in a healthy weight range by how much body fat you have and also by your general health. BMI can be a little trickier however than working out your healthy weight range using body fat.
The reason that BMI is not always accurate is because if you have a lot of muscle then your BMI might not be right. Muscles weighs a lot more than fat but will take up less space than fat so some people can have a lot of muscle but they don't look all that big. BMI doesn't take this muscle weight into account. If an athlete, football player, body builder, wrestler or anyone that gains a lot of muscle through their exercise routine, will actually calculate a BMI that puts them in the overweight or obese range.
So BMI isn't accurate for people who have a lot of weight in muscle, but what about everyone else? Well the accuracy will vary between people with different situations. Children don't get an accurate BMI and also very tall people might not get an accurate BMI either due to the weight of their longer bones. So generally, if you are extremely tall, a child or have a lot of muscle then BMI isn't a good way to measure your weight range.
The other inaccuracy with BMI is that it uses the same formula for both men and women, however women will generally carry more body fat than men so for that reason you would think the formula would be a little different to give accurate results.