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Fat test fails on sports stars
THE body mass index that doctors use as a guide to determine if patients are a healthy weight has rated some of our elite Olympians as fat.
Experts have questioned the accuracy of the body mass index after calculations showed cyclists Anna Meares, Shane Perkins and Scott Sunderland, ironman Ky Hurst and boxer Johan Linde had readings over 25.
The BMI is calculated by dividing a person's weight in kilograms by their height squared and then compared against a set table which rates a result of 25 and over as overweight and 30 and over as obese.
For example, Johan Linde's height is 1.98m, which multiplied by itself gives a figure of 3.92. When his weight of 104kg is divided by 3.92 the result is a BMI of 26.53, which would make the boxer technically overweight.
Sunderland and Perkins, both Commonwealth gold medallists, have BMI readings close to 30, making them almost obese on the scale, which ignores muscle to determine if a person is a healthy weight.
Nutritionist Susie Burrell said Hurst, who has won seven Australian ironman titles, had body fat totalling 6 to 8 per cent.
She said athletes had to use more sophisticated testing than the BMI.
"BMI doesn't take into account body composition or where the fat mass is held," Ms Burrell said.
"In general, we work off skin folds or DEXA scans (low energy X-rays) which tell us exactly how much fat and muscle a person has.
"If you look at Ky Hurst, I think his body fat is 6 to 8 per cent which is low. He has an enormous amount of muscle mass."
Australian Institute of Sport head of sports nutrition Dr Louise Burke said the organisation also favoured the DEXA scans over BMI to asses an athlete's physique.
But the Australian Medical Association has backed the measure. President Steve Hambleton said: "No measure is going to be perfect because we all come in different shapes and sizes.
"But the BMI is a very good guide and tells a great majority of people where they should be."