Body Mass Index (BMI) Flaws Mean a Piece of String Could Work Better

Since its inception body mass index or BMI for short has been the yard stick test for measuring body fat. New research (and a piece of string) now shows that it’s in no way a perfect science.

Body Mass Index test has been around for quite a while now. For some time we have known it is not a perfect method for measuring body fat but it’s been agreed that it can be used as suitable guideline to help with obesity and weight loss. New research by Dr. Margaret Ashwell and Oxford Brookes University has now fully exposed the flaws of BMI using a piece of string as visual aid.

BMI test quick facts.

BMI was conceived in the early 1800’s by Belgian Polymath Adolphe Quetelet. He came up with the formula which is used as a test for measuring obesity which he called the Quetelet Index of Obesity. This was then fine tuned into the following formulas:

  1. Imperial English BMI – weight (lbs) x 703 ÷ height (in2)
  2. Metric BMI – weight (kg) / height (m2)

BMI has only been used as a global standard since the 1980’s when there was a rise in cases of obesity across the western world.

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The trouble with Body Mass Index (BMI).

The problem with Body Mass Index (BMI) is a two-fold problem that can’t account for important body shape variables. For example, if a person is exceptionally muscular such as a bodybuilder, the standard BMI calculator will show them as being overweight or obese. You only have to look at them to realise how far off the mark is kind of assessment is.

“BMI gives us an idea of total fat mass, but doesn’t tell us where the fat is located in our body,” “Fat distribution can give us an idea of whether a person is at an increased risk of mortality.” W. Scott Butsch – MD Harvard Medical School

The other more significant problem is that if a person is a fairly standard shape all over but has a lot of belly fat the current BMI test may give them the all clear from a weight loss perspective. This means a lot of people are not being diagnosed properly and never receiving the treatment they need.

“If you are measuring waist-to-height ratio you are getting a much earlier prediction that something is going wrong, and then you can do something about it.”Dr. Margaret Ashwell – Oxford Brookes University

BMI string test and WHtR (waist-to-height ratio).

In a new weight and health assessment study conducted in Oxford Brookes University a new method has gained a lot of ground. WHtR (waist-to-height ratio) which can be conducted with a piece of string has been shown as a test to be a much better indicator of a person’s weight status and possible obesity.

Ashwell Shape Chart - Alternative to Body Mass Index Chart

Ashwell Shape Chart – Alternative to Body Mass Index Chart

The problem is that white fat which generally gathers around the waist can be missed by a regular BMI test. With WHtR (waist-to-height ratio) you measure your height with a piece of string and then fold the string in half and wrap it around your waist to see if it will comfortably fit your circumference. If you fail the string test you should consider seeing your GP or attending a weight loss clinic.

“The beauty is that you can do it in centimetres or inches, it doesn’t matter. We have got increasing evidence that this works very well with children as well, because whilst they grow up their waist is growing but also their height.” Dr. Margaret Ashwell – Oxford Brookes University

The study of 3000 people showed that at least 12% of people suffering from obesity or being overweight would be completely missed using the current BMI method.