Is BMI a Load of BS?
Is BMI a Load of BS?
It's possibly THE most popular measure of health in the world...
Yet many health professionals now believe it to be one of the biggest scams ever devised.
Billions of people across the world are affected by the health measure known as Body Mass Index (BMI) — from people who must pay higher insurance premiums due to a high BMI, to people seeking psychiatric help for having too low of a BMI, and everybody in between.
So is the BMI really as good or bad as the proponents and opponents would have us believe?
Well, like most things in life, the truth is somewhere in between these two extremes. Let me explain...
BMI is simply a measure of the ratio between your weight and (for you math junkies, squared) height.
Originally people between 18.5 and 27 were considered “normal weight”, and anybody over 27 was considered “overweight”, with higher numbers considered obese.
However, due to pressure to match international standards1, in 1998 the National Institute of Health (NIH) dropped the overweight threshold to 25 — you can see the new standards2 for yourself:
Underweight = <18.5
Normal weight = 18.5–24.9
Overweight = 25–29.9
Obesity = BMI of 30 or greater
Studies have shown a general trend towards higher BMI and more health problems (diabetes, heart disease, etc.) — after all, you can only pack so much weight onto a frame before it starts to take a health toll.
However, there is a problem when you take this generalization and apply it to specific situations.
First of all, it doesn't account for what kind of weight your body holds. Many athletes and body builders will have high BMIs because of the muscle on their bodies — but BMI doesn't discriminate between muscle and fat. Needless to say, if you have a high BMI because of muscle build, you won't suffer the same kinds of medical problems as someone who has a high BMI because of belly fat.
Second of all, there is what’s called the “obesity paradox”. What scientists have found is that of people who were diagnosed with type 2 diabetes and metabolic disorder, those classified as “overweight” or “mildly obese” actually lived longer than those classified as “normal weight”.
It should come as no surprise that many diet food and drug manufacturers are funding a lot of the studies behind BMI — the more these companies can convince people that they are overweight, the faster products will fly off the shelves.
As I mentioned, while BMI is a good indicator for general health — like for use in public health studies — it's not the best measure for individual health...
In fact, that's just what the inventor of the BMI said before medical professionals and government officials bastardized it for their own misuse:3
The BMI was introduced in the early 19th century by a Belgian named Lambert Adolphe Jacques Quetelet. He was a mathematician, not a physician. He produced the formula to give a quick and easy way to measure the degree of obesity of the general population to assist the government in allocating resources. In other words, it is a 200-year-old hack.
Luckily doctors are starting to wise up and recommend a more accurate measure: your waist-to-height ratio.
Since most people tend to collect unhealthy fat around their waists, this measure tends to be much more accurate than BMI.
So if your doctor still records your BMI, it may be wise to request the waist-height measure instead.
Not only will you get a more accurate idea of your health, but with insurance companies often charging for high BMIs, you could end up saving a decent amount of money.
Yours in health,