Why Do We Keep Using BMI?!


How many times have you said or heard from friends, "I want to lose weight because my 'ideal weight' is X kilos"? Or heard someone say they are "overweight" because they are far from that ideal number even though they do not look like a stereotypical "overweight person"? Where does this 'ideal weight' come from, and why are people so concerned with BMI?! 

As a personal trainer and a fitness nutrition specialist, I am deeply concerned by the fact that this formula is still being used nowadays and even taken as an excuse by some health professionals and insurers to avoid offering care to some individuals. Apparently, in some countries like the Netherlands, even covid-19 vaccinations were being offered at early stages by taking  BMI as a health indicator instead of other more critical factors that determine a person's health status.

Still, confused about what I'm talking about? Let's retrocede and start with some basics... The formula of BMI is intended to determine a person's ideal weight according to his 'health.'

BMI = Weight (in kilograms)/ Height (in m2)

BMI Ranges:
< 18.5 ­– Underweight  
18.5 – 24.9 – Healthy
25 – 29.9 – Overweight
 30 – 39.9 –  Obese

Who invented it? 

Adolphe Quetelet, a Belgian astronomer, and mathematician, originally developed this formula between 1830 to 1850. Initially, this formula was known as Quetelet Index until it was renamed. In order to develop his formula, he used data from predominantly European men to measure weight in different populations. Aldophe soon realized that THIS FORMULA SHOULD NOT BE USED FOR HUMANS, but physiologist Ancel Keys had some other plans!
Ancel Keys reintroduced the BMI formula in 1972, naming it the Body Mass Index. Since then, this formula has been extensively used by medical and nutritional practitioners.

How Is This Formula Used?

BMI is used to assess a person's health based on his weight & height. It is mainly used to determine the amount of fat mass you have that will ultimately reflect overweight or obesity if you have a higher BMI.

But have you ever wondered? If your BMI says you are overweight or obese, what is the cause of your weight gain?

Are you gaining weight out of nowhere, and now you should start a strict diet to lose all that excess weight? Or should you get yourself thoroughly examined and then investigate the exact underlying cause of your weight gain?

Why BMI is Problematic: 

The problem with this formula is that it has serious limitations. Firstly, it is very old and does not comply with the current health metrics and problems. Secondly, it neglects all factors like an individual's race, background, lifestyle, physical activity, or even body composition.

Every human is built differently. One may have more muscle mass than the other, while the other person may have more fat mass than the first person. Similarly, it fails to reflect body fat distribution as states individuals as overweight.

From the National Center of Weight and Wellness, Scott Kahan says that BMI is not an accurate measure to evaluate body fat because sometimes it labels muscular individuals as overweight who are not actually overweight.

Additionally, BMI does not cater to every category, from adolescents to adults and older people. Since this formula was predominantly derived from the data based on European men, it also does not cater to people from other regions and races.
In short, one formula doesn't fit each category of age.

BMI Does Not Recognize Internal Body Health:

Now my second major concern...

Nowadays, nearly half of the overweight population is healthy by other health factors like blood glucose levels, cholesterol, blood triglyceride levels, and blood pressure. Their problem is usually just superficial, like a sedentary lifestyle or overeating.
This doesn't seem like a problem, right? Now listen!

What about those people who are healthy according to their BMI but their other health metrics are skyrocketing? They are hypertensive; they are diabetic, their cholesterol and blood triglyceride levels are high, BUT their BMI is normal.

This is the main problem with this formula. Your health practitioner may calculate your BMI and label you as 'healthy.' But internally, your organ systems may be shattering on their own because they weren't monitored merely with a formula.

What Can Be Done to Measure Health Better?

  • When a patient walks in, their body composition, lifestyle, dietary choices, and blood reports everything should be taken into account to assess their overall health.
  • Use scales that help in determining your muscle and fat mass as well as visceral fat.
  • A proper questionnaire with detailed questions about lifestyle and dietary habits can also be used to gauge a person's health.

Wrapping Up!

In my eyes, a person's health cannot be and shall not be assessed based only on their weight. At times, one person may weigh more because he/she has a higher muscle mass. So a higher BMI will not do justice to his/her muscular body. 

Furthermore, BMI should never be used as an excuse to neglect, discriminate or deny health care for individuals. 

Ask questions, monitor blood reports, use scales, and do not rely upon formulas developed by a mathematician who knew nothing about well-being for assessing your patients or clients' health.  

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