Body mass index, or commonly referred to as “BMI” is a measure for gauging the total fat content in your body. The idea of the measure was first considered in the nineteenth century by Lambert Adolphe Jacques Quetelet. However, due to his narrow focus on men, it was never fully adopted until 1972, when Dr. Ancel Keys developed a standardized calculation for the measure, W/H2. This calculation would become known as BMI. In leman terms, the calculation means your body weight divided by your height in meters2 will determine your position on the obesity scale. Subsequently, a BMI of 18.5 or less is considered underweight, 18.5 - 24.9 is normal, 25 – 29.9 is overweight, and anything above 30 is considered obese.
Why Does BMI Matter?
In general, an individual with a high BMI is considered to be a high-risk candidate for developing a range of negative health conditions. These negative health conditions are often linked to excess weight and include problems such as diabetes, arthritis, liver disease, several types of cancer, like breast cancer, colon cancer, and prostate cancer. Having a high BMI could also indicate susceptibility to high blood pressure or hypertension, high cholesterol, and even sleep apnea.
All of these potential health risks, coupled with the fact that nearly 3 million people die worldwide from obesity on a yearly basis, make the BMI an important medical gauge to consider.
Is BMI Accurate?
As helpful and important as BMI can be, it can sometimes prove to be inaccurate. The measure is very broad and unfortunately does not take into account many other factors that could make someone obese or not. For this reason, it is important to understand that the BMI is not a conclusive measure. It does not directly measure the actual body fat content in a person, rather it gives a guide to where the “normal” person should be in the index. This can especially be difficult to unpack especially when dealing with people who live very different lifestyles and have different body types.
One area where BMI often reveals its flaws is when it comes to athletes and bodybuilders. According to the calculation BMI = W/H2, which puts athletes at a disadvantage because of their heavier weight. Of course, some athletes do weight a lot, especially with the likes of most bodybuilders and some combat professionals, however, the important component that is missing here is that athletes are often muscular, and muscles weigh more than fat. For this simple reason, someone who is very muscular and does not fall into the designated height range may be considered obese, though they have a relatively low body fat percentage. The opposite of this is true for some senior individuals who have lost a lot of muscle. In their case, BMI tends to underestimate the amount of body fat they carry.
BMI is also not a great gauge for overall health. As mentioned earlier, it does not take into account the lifestyles people live. For example, an individual with a lower BMI who may pass as “normal”, could have underlying cardiovascular issues because they smoke, however, an individual who actually lives an active lifestyle and does not smoke may pass as overweight or obese with the assumption that they are more prone to developing cardiovascular issues.
Needless to say, the BMI is not a good gauge for overall health status, nevertheless, it can be a helpful tool to determine potential risks that may lie ahead for an individual. At the end of the day, the BMI measure is about 80% accurate at all times and therefore should not be ignored, however, there also shouldn’t be as much importance placed on the measure itself when looking at overall health.