What's the deal with BMI
Updated: Aug 8, 2022
BMI, or Body Mass Index, is a simple measure of your weight for your height. In a way, it is an overall indicator of obesity, as someone who is heavier relative to their height is likely to have more body fat. If we look at large groups of people, there is a correlation between BMI and overall health and chronic disease risk. Because of this many government agencies and life insurance companies use BMI as a simple measurement of one's overall health and risk of long term disease.
The Body Mass Index equation is your weight in kilograms divided by the square of your height in metres. Scroll down to the bottom of this article for a link to an online BMI calculator.
A BMI of 18.5-24.9 is considered normal weight, with anything lower than 18.5 being underweight. 25-29.9 is overweight for BMI, and any measure over 30 is assessed as being obese.
There is some contention about BMI, which is mostly due to the influence of muscle mass on the measurement. Since muscle is quite a dense tissue, someone with a larger amount of muscle can have a low percent body fat but may still be considered overweight via the BMI equation.
With that being said, most North Americans are in fact overweight due to having too much body fat and would enhance their health and long term vitality by losing some fat mass. While not every body will fit into the ideal range for BMI, moving towards that range will most likely increase health and decrease risk of chronic disease.
So BMI isn't the end all be all of body composition but it does have some merit for both men and women when assessing general health status. For a more complete picture of your body composition and health risk, a BIA scan is a great way to go and will give you much more information to go on as you improve your nutrition and training.