Jane McCredie: Time to put the weights on obesity

I RECALL seeing a TV comedian talking about obesity figures that showed Australia riding high in the international rankings.

“Is there anything we’re not good at?” he quipped.

Well, if there was a gold medal for obesity, new figures suggest Australia would be a serious contender.

A landmark global study of more than 9 million people in nearly 200 countries shows the United States still outweighs other high-income countries, with an average body mass index (BMI) of 28.5 for men and 28.3 for women.

But Australia is not far behind, at 27.6 for men and 26.9 for women.

It’s a sobering thought that being overweight is now the norm in this country.

In a series of papers, published in the same issue of The Lancet, the researchers looked at worldwide movements in average BMI, systolic blood pressure and serum total cholesterol between 1980 and 2008. Average BMI increased globally over the period, leading the researchers to estimate that 1.46 billion adults were overweight by 2008.

When it came to measuring the biggest rise over the period, Australia came in third among high-income countries, behind the US and the UK.

The situation is even worse in some nations that will least be able to afford the catastrophic health consequences of this tsunami of obesity: the average woman in Nauru now has a BMI of 35, and rising.

For developed countries such as Australia, though, there may be a surprising glimmer of hope in the new data.

While we keep getting fatter, the global study shows that some key associated risk factors are actually improving, at least for cardiovascular disease (diabetes is another question).

Between 1980 and 2008, mean systolic blood pressure fell in Australia and New Zealand by 3.9 mm Hg per decade for women and by 2.3 mm Hg per decade for men.

Serum total cholesterol is, unsurprisingly, highest in wealthy countries, including Australia, but it also fell slightly in these countries over the period, despite increasing in other parts of the world.

This could just be a medical success story, albeit one with a mixed prognosis: Australians seem to be getting better at managing some of the risk factors that accompany our expanding waistlines, despite our marked failure to actually tighten our belts.

Given the intransigence and multifactorial nature of the obesity problem, it is some consolation that good medicine appears to be at least helping us to live more healthily with that extra weight.

But if anything underscores the need to make prevention a key part of the on-again, off-again process of national health reform, it is data such as these.

If we want to avoid the devastating health consequences ― and crippling financial costs ― of the obesity epidemic, we need to devote some serious resources to effective management of associated risk factors as well as finding creative ways to address its root causes.

Jane McCredie is a Sydney-based science and medicine writer, and author of Making girls and boys: inside the science of sex, published by UNSW Press.

Posted 21 February 2011