The latest figures from the Australian Bureau of Statistics (ABS) show that Australians are just as likely to be overweight as to be in a normal weight range. That's a disturbing trend, but in part reflects the definitions used for those conditions.
According to ABS data for 2007-2008 (the newest figures available), 37% of Australians aged over 18 are overweight, and the same number are of normal weight. 24% are classified as obese. Both conditions are measured by using body mass index (your weight in kilograms divided by the square of your height in metres). A BMI above 25 is classified as overweight, while above 30 is obese. (My own BMI falls in the overweight category, as it happens.)
When the two figures are combined, 61% of Australians are either overweight or obese. That average conceals a notable gender variation: for men, the figure is 68%, while for women, it is 55%. The rates also rise as people get older, and, as the chart shows, have risen over time.
The key point of dispute over these measures is that BMI doesn't distinguish between 'good' body mass (muscle) and 'bad' body mass (fat). In theory, if we had all become gym junkies and bulked up, we'd qualify as overweight even though we had become fitter. That said, a quick glance around any local shopping centre suggests that hasn't happened.