Did you know that the Body Mass Index (BMI), the mathematical formula based on your weight and height, which has been used for decades to define if you are at ideal weight, overweight, or obese, was actually never designed to assess individual health?
Indeed. The BMI was developed in 1832 by the mathematician Adolphe Quetelet to find a statistical pattern of the population, not to diagnose obesity or predict health risks! The purpose was only to define a mathematical model describing the “average man” and nothing more.
So, how did a formula created for population statistics end up being used by doctors and health specialists to this day?
Although overlooked for decades, in the 1970s it resurfaced as it was recognized as a practical method to evaluate obesity in large populations. Around the 1990s, the World Health Organization (WHO) officially adopted it because it was a simple, practical, and cost-effective method. From then on, standardized tables emerged, still used today as the main criteria to define obesity and assess health.
The problem?
The human body is much more than a mathematical calculation. BMI has glaring flaws:
• Does not distinguish muscle from fat → An athlete can be classified as obese simply for having more weight (due to having a strong muscular build)
• Ignores fat distribution → Abdominal fat is not differentiated from subcutaneous fat
• Does not measure metabolic health → People with BMI within the “normal range” can have inflammation, insulin resistance, and other issues, while some with high BMI can be metabolically healthy.
Practical example:
Imagine a 30-year-old man with high muscle mass and low body fat. By BMI, he could be classified as obese. However, when analyzing body composition and biochemical tests — cholesterol, blood sugar, inflammation — markers could indicate excellent health. At the same time, another person with a "normal" BMI and sedentary habits might have excess fat and a higher disease risk.
This is the big mistake of BMI: confusing weight with health
The good news?
BMI is finally being questioned. Recently, a group of experts published a report in the journal The Lancet Diabetes & Endocrinology, proposing new ways to assess obesity. The idea is to move away from BMI as the sole criterion and consider other relevant factors, such as body composition, associated signs, and symptomatology.
They suggest two new classifications:
• Clinical Obesity: when there is excess body fat accompanied by related health problems, such as heart disease, hypertension, and insulin resistance.
• Pre-Clinical Obesity: when there is a risk of developing these conditions but no obvious symptoms yet.
This completely changes how we evaluate obesity. And it makes perfect sense! After all, health is not just a number on the scale or a simplified mathematical formula.
Now, the big question: Is this new classification already in use?
Not yet, despite the challenges and difficulties this change may bring, I believe it is an important step for doctors and health professionals to adopt a more conscious, precise, and fair view when assessing people's weight and health.
Author: Rita Marques:
"My name is Rita Marques, in addition to being a perfectly imperfect woman, I am a nutritionist passionate about helping people find balance between body and mind. My passion was born from a desire to understand how food impacts the body, mind, and emotions, directly influencing our well-being. From an early age, my life was marked by sports practice and a demanding relationship with body and food, which awakened in me the desire to explore nutrition more deeply. This interest led me to realize that nutrition goes far beyond numbers or aesthetic standards; it is an essential tool for taking care of ourselves holistically.
Today, in my professional work, I dedicate myself to helping people build a healthier relationship with food and themselves, respecting their individuality and promoting balance."
