BMI (Body Mass Index)
Most people in their professional and work lives develop little irritations about how certain things are presented to the public, by press and government; this is one of my mine.
In recent years there have been very rapid changes in health policy, a lot of which have been good an my opinion such as legislation regarding smoking, car emissions, seat belt use, a few years ago Jamie Oliver’s healthier food in schools and hospital campaigns etc. Most of these have laudable aims few would disagree with. Most recently (last few decades at least) we have had a ‘fat is bad’ approach to dietary education and public information. That has now been turned on its head in that the new ‘big bad wolf is sugar. This is all connected with the rising tide of obesity in the population along with the accompanying prevalence of diabetes, osteoarthritis, cardio vascular disease, hypertension, gall bladder disease, etc.
One of the common measures used to estimate your relative level of obesity is ‘BMI’. The ‘basis’ for BMI was devised by Adolphe Quetelet from 1830 to 1850 a Belgian astronomer, mathematician,statistician and sociologist. (Ref Wikipedia). Since then a few things have changed, for instance the average human height has gone up by 10cm in the last 150 years and we are not just statistically evaluating a specific closely related mid-European, ethnically consistent population now. Different countries and regions/ ethnically specific areas have differing versions of BMI because an Eskimo, Masai-Tribesman, Orientals, Scandinavian, or Anglo-Saxon do not tend to have the same overall shape and the basic calculations just does not work.
The modern term “body mass index” (BMI) for the ratio of human body weight to squared height was coined in a paper published in the July 1972 edition of the Journal of Chronic Diseases by Ancel Keys. There have been many arguments against the reliability of this measure especially specialists in the field and specifically how ‘individuals’ fit into this statistical model.
So how is BMI used in the UK in 2024? Well if you want to have a straightforward measure of obesity which is easily calculable and applied to the majority of the population then this sounds like a fantastic way of doing it, right? Unfortunately not really. The problem is that it does not take into account body types (Ectomorph: tall thin, lightly muscled, Mesomorph: athletically built well muscled, Endomorph: round, fat poorly muscled) and is designed to be used more in population statistical analysis; so quite poor in determining the relative fatness of an individual.
We therefore have a measure of relative fatness, height to weight, that does not differentiate between whether that weight is due to muscle (heavier than fat) or adipose tissue (fat), which is being used inappropriately on individuals not populations, that was designed in the 19th century, re-interpreted in the 1970’s does not take into account enormous changes in population heights, ethnic variations or body types. Now we are applying this to life insurance policy assessments, armed services and police recruitment, job security/ health checks, and children at an early stage of their education.
If we look at the last case that of children, BMI is now being used in schools. If your child is outside the ‘norm’ according to BMI you are referred to your GP. As a result children are being medicalize at an early stage of their life, taking perfectly normal fit muscular children and putting them on diets unnecessarily because an over-zealous and rigid application of BMI is used, and scaring the hell out of their parents unnecessarily as a bi product. All this because we want an easy measure of how much fat we are carrying and like to make it ‘easy’ for a non medical bureaucrat to do the testing and referring, rather than looking at the individual and following a sensible approach which seems a far more reasonable way to proceed.