Body Mass Index, more commonly known as BMI, is used to calculate whether one is in the healthy weight range. The calculation is your weight in kilograms divided by the square of your height in metres. If your resulting number is between 20 and 24.9, congratulations, you fall into the normal weight range. You’re considered obese if your number is over 30.
However, BMI has one major flaw – it cannot differentiate fat from muscle. So those who have a lot of muscle mass may find themselves being described as overweight or obeseeven though this may not be the case.
For the same reason, BMI is also tricky in older people. Since we tend to lose muscle mass as we age, we might stay at the same BMI (or it may even decrease)while ourratio of fat to muscle shiftstowards fat.
So is there another way to go about this?
One alternative is to measure your waist circumference – it was once the mainstay of the Federal Government’s ‘How Do You Measure Up?’ public health campaign, which stated that a waistline of greater than 94cm in men and 80cm in women putthem at increased risk of chronic disease, such as heart disease and type 2 diabetes.
The reason your waist circumference is a good indicator of healthis because it reflects fat distribution, and is a better indicator of visceral fat – the fat that sits around your vital organs, which is unhealthy and is more likely to be associated with the high-risk ‘apple’ body shape in comparison to people with a ‘pear’ body shape.
The best way to measure your waist circumference is to stand upright with your stomach relaxed (no sucking in your tummy!), then run a measuring tape around your midriff to where you get the greatestwidth. The general aim is to go for the biggest possible measurement.
A 2014 study published in the journal Obesity found that the 12-year incidence of obesity in Australians was 15 per cent when defined by BMI, and 31.8 per cent when defined by waist circumference. Based on these results, the authors argued that waist circumference should be used more often when studying obesity and associated disease.
What do you think? Have you ever measured your BMI and waist circumference to see how they compare? If so, did they give you different indications about your weight and health?
