‘BMI’ is meant to stand for ‘Body Mass Index’, a calculation based on your height and weight and something medics have been telling us for years reflects how healthy we are. But it is misleading. Your BMI is calculated by taking your weight in kilos and dividing it by your height in metres squared. If it is between 20 and 25 you are supposed to be in the healthiest bracket, but if it is 25 to 30 you are supposed to be overweight, whilst a BMI of over 30 renders you obese.
Blunt tool
But it is oversimplistic – a blunt tool which is often inaccurate and just plain wrong. It does not distinguish between weight from lean muscle mass and that from fat. So, your average rugby scrum front rower or body builder would be classified on this basis as obese, when in truth they are built like Panzer tanks and very fit indeed. It also explains why broad shouldered, active schoolchildren and teenage swimming champions often bring home a ridiculous letter from school saying they are overweight and need to diet.
I am all in favour of carrying out serial measurements on children as they grow, to alert them and their parents of the need to avoid future obesity and attendant health problems, but the measurements have to be accurate. The BMI frequently is not.
All you need is a tape measure!
Now, researchers at the University of Copenhagen have concluded that people with a BMI of 27 are the healthiest as they have the lowest death rate from any cause, compared to people with other BMIs. They suggest we alter the healthy BMI range upwards 3.3 points to reflect this.
This is all well and good, but we still wouldn’t know whether it’s the muscular people, or the fatter people with the same BMI, who are the healthiest, would we?
So, here's what I think we should do. Measure our height and our waist. If our waist isn't less than half our height, we are overweight. How simple is that? It works for all ages, both sexes and all races. All you need is a tape measure. No calculations either.
It also means no more healthy children being classified as overweight either. Good news all round!