THE health of thousands of Australians is being put at risk by a discredited measurement system that grossly miscalculates a person’s healthy weight.

The Body Mass Index, or BMI, has long been used to determine if a person is “overweight” or “obese”.

But because all it does is compare your height with your weight, the BMI takes almost no account of whether your weight is made up of fat or muscle.

An analysis of the country’s top NRL athletes shows how ridiculous this measurement is by finding most of the sport’s fittest players are classed as either overweight or obese.

Cronulla skipper Paul Gallen, Broncos back-rower Sam Thaiday, Dragons prop George Rose and Rabbitohs’ George and Tom Burgess are among the dozens whose weight and height measurements put them in the obese category, while more than 150 players are rated as overweight.

These include Origin legends Johnathan Thurston and Billy Slater and former Golden Boot winner Benji Marshall. The few in the top eight in the “healthy” range include Joe Boyce, Justin O’Neill and Kyle Stanley.

Leading sport and exercise physician and former Sports Medicine Australia president Peter Larkins believes the BMI is a misleading tool.

“In sport it’s almost irrelevant,” Dr Larkins said.

“The BMI obviously looks at a certain index of weight to height, but we know in athletes their weight is muscle and so their absolute weight on the scale is a significant weight.’’

Dr Larkins said underwater weighing, ultrasound measurements, hip and waist measurements and the skinfold pinch tests were far more ­effective in determining a person’s healthy weight.

A recent study from the University of Newcastle found that almost a third of those who were assessed using the BMI calculator alone were wrongly classified as obese.

The study took a broad section of Australian women and highlighted the need for body measurements, percentage body fat and muscle mass to be introduced into obesity testing instead of using the BMI.

A WAIST OF TIME

THE Body Mass Index, or BMI, measures how healthy you are by comparing your weight to your height — but it takes almost no account of whether your weight is made up of fat or muscle.

Anyone with a BMI score over 25 is “overweight”, and anyone over 30 is “obese”.

By that reckoning, these 10 NRL athletes are all obese:

* George Rose (BMI: 36)

* Sam Thaiday (BMI: 33)

* Greg Eastwood (BMI: 33)

* Paul Gallen (BMI: 32)

* Glenn Stewart (BMI: 32)

* George Burgess (BMI: 31)

* Tom Burgess (BMI: 31)

* Jared Waerea-Hargreaves (BMI: 31)

* Trent Merrin (BMI: 31)

* Greg Eastwood (BMI: 32)