BMI

I am sure you all must have come across the term BMI. Yes, it’s a scale to measure weight range from underweight to Obese. You may even have BMI app in your smart phone. I mentioned in my last post, that BMI is a flawed concept. It doesn’t reflect the degree of obesity of an individual.

Body Mass Index is based on the height and weight of a person.  It does not take into account muscle mass, bone density, overall body composition, race and sex differences.

Here is the BMI equation:  BMI = weight in kilograms divided by height in meters squared.

BMI equation or formula was derived in the early 19th century by a Belgian astronomer, mathematician, statistician (NOT a physician) called Lambert Adolphe Jacques Quetelet, to provide a statistical data to a government, by an quick and easy way to measure the degree of obesity of the general population.

Quetelet derived this quick tool, for general population only NOT applicable to an individual. In other words, Quetelet derived BMI formula for government statistical needs, NOT for Physiology. 

Quetelet, didn’t provide a valid physiological reason to square a person's height and left behind the waist measurement, which is a key factor to define the degree of obesity. Abdominal fat affects organs like the kidney, liver and the waist circumference is the clear indication of abdominal fat levels.

BMI formula goes awry for a person with person with strong bones, lean muscle and low fat will have a high BMI or obese!! Also, BMI hyperbolizes thinness in short people and fatness in tall people.

It’s totally unacceptable to have very sharp boundaries (just a decimal place) to distinguish the obesity level underweight (Below 18.5), ideal (18.5 – 24.9), overweight (25.0 – 29.9) and obese (30.0 and above).

Let’s be honest to ourselves,  Its not a Medical or Engineering entrance cutoff mark to have a decimal place accuracy. Physiological limits cannot up to a decimal precise.

Studies have proven that, Waist size linked to risk of diabetes, CAD, CVD, regardless of BMI. Waist-to-height ratio is a better indicator to measure the degree of obesity than BMI.

Then why the medical associations around the world, continue to practice this 200-year-old hack? Because medical insurance /Food/ fitness industries lobbies the medical associations to continue the BMI, in order to keep their business alive. (Medical insurance companies charge higher premium for high BMI, to sell more breakfast cereals, Fitness club and gym membership and buying of fitness equipment)

The flawed BMI formula, puts several millions of Americans into overweight or obese category but, the fact is they are “perfectly healthy.” The more dangerous is that it also puts millions of people, whose BMIs in the “normal” range, but are actually considered “unhealthy” based on their other physiological markers. Below is the published article for your ready reference.

BMI puts most of the Olympic sprinter (Swimmers and Athletes) or Wrestlers (who are build, lean and toned muscles) into Overweight to Obese range!  Because, muscle weighs more than fat.  Example, 182 cm (6ft) tall Olympic 100 meter sprinter weighing 90kg may have the same BMI (26) of a sedentary person's waist of 96 cm (38'') of the same height and weight.

So, what is the correct way to measure? There are couple of equations available online, which include the waist size, sex, race etc. but, the simple screening tool that I follow is waist to height ratio. I.e. waist circumference should be less than half of your height.  

                                        

                                             Waist circumference      =     <Half of Height

Example,  182 cm (6ft) tall should have a waist circumference of  91 cm (36") or less.

So, don’t focus on reduction of weight, rather focus more on reducing the waist size, in order to live healthy. The HFLC diet ensures the considerable reduction on the waist size, as a brownie point for you lose the weight as well.