Sydney University nutritionist Jennie Brand-Miller holds out a tempting message for sweet tooths and companies like Coca-Cola: sugar is not to blame for obesity in Australia.

The Australian Paradox is the title of a scientific paper Professor Brand-Miller and Australian Diabetes Council research adviser Alan Barclay wrote which seeks to show that while obesity rates continued to swell, refined sugar consumption has fallen in recent years.

Mainstream nutrition experts have distanced themselves from the finding but the food industry and Coca-Cola have seized on the study to oppose tougher advice against sugar in Australia's diet bible.

The Australian Dietary Guidelines, currently being finalised, are the subject of intense pressure from food companies urging a good word for their product. The guidelines will be released later this year.

Public health advocates are uneasy at the way the food industry, and particularly the sugar sector, is contesting the concerns about sugar and health.

Queensland Senator Ron Boswell went into bat for the sugar industry in the Senate recently, deploring an article in the influential science journal Nature titled, ''The toxic truth about sugar'', which he said sought to ''demonise'' sugar by comparing it with alcohol.

Professor Brand-Miller was reported as being ''disgusted'' by the Nature article.

In The Australian Paradox, she and Dr Barclay challenge the view linking sugar with obesity, saying the statistics show that in Australia obesity has risen three-fold while consumption of sugar fell by 16 per cent in the 23 years to 2003.

In formal submissions, both the Australian Food and Grocery Council and Coca-Cola cite the paradox study to counter the call in the draft dietary guidelines for a reduction in consumption of sugary food and drink.

The paradox study has drawn a fiercely critical response from economic commentator Rory Robertson, who believes in a fructose-free diet through which he says he shed 10kg over eight months, without extra exercise.

Mr Robertson says the paradox argument relies on misinterpreted statistics, some of which are no longer collected because of unreliability. Professor Brand-Miller responds that Mr Robertson is not a nutritionist and does not understand nutrition. A prominent expert on obesity issues, Boyd Swinburn, has reviewed the arguments from each side and comes out broadly on Mr Robertson's side.

Professor Swinburn said the paradox study's summary of the data as showing ''a consistent and substantial decline in total refined or added sugar by Australians over the past 30 years'' belied the actual data shown ''and is a serious overcall in my opinion''.

''The ecological trends of sugar and obesity are pretty well matched and I do not believe there is any paradox to explain,'' said Professor Swinburn, who, is director of the World Health Organisation Collaborating Centre for Obesity Prevention at Deakin University.

Professor Brand-Miller told Fairfax that the emphasis on sugar in diet was ''overblown'' and not enough attention given to refined starches' role in obesity.

She and Dr Barclay are principals of the Sydney University Glycemic Index Foundation, a not-for-profit organisation which seeks to promote with consumers and food suppliers healthier carbohydrate foods - those that are digested slowly with benefits to blood glucose and insulin levels.

The foundation is associated with low glycemic index (GI) products, including a ''low GI cane sugar'' brand manufactured by CSR.

CSR and other companies pay licence fees for a GI symbol.