"Sugar consumption in Australia appears to have been relatively stable in the three decades following the end of World War II but since the late 1970s, there has been a substantial decline," author Bill Shrapnel said.

"To put the decline in consumption into context, by 2011, Australians were each consuming 8.3 kilograms or 39.5 cups of sugar less per year compared to 1970."

Meanwhile, the World Health Organisation has named and shamed sugar as a big player in the obesity epidemic.

In Australia, rates of obesity have soared 80 per cent in 30 years and the nation is the third-fattest country in the developed world.

So, how does that data and the new sugar consumption data add up?

It doesn't.

"Nutrition and health is more complicated that just one nutrient. Increased refined carbohydrates, less vegetables, wholegrains and fibre, as well as less physical activity, all have a role to play," says accredited practising dietitian Jessica Bailes.

Dietitian Susie Burrell agrees, adding that the study only accounts for table sugar consumption.

"While [refined table] sugar may have declined, this analysis excludes other added sugars, e.g. honey, glucose, fructose, so is one part of the sugar story only," Burrell says. "Sports drink, for example, uses both sucrose and maltodextrin to sweeten, so sugar is only part of the story.

"Looking at supermarket products, honey is frequently used, as is glucose, which may explain why sugar itself has not increased as manufacturers look for clever ways to disguise sugar."

Not including other types of sugar is only part of the problem.

The paper, published in the European Journal of Clinical Nutrition, is based on research from The Australian Paradox report, which used inaccurate Australian Bureau of Statistics (ABS) data.

"Basically, the ABS statistics – conducted over 40-odd years – were discontinued in 1998," I Quit Sugar author Sarah Wilson explains. "The reason they [were] discontinued was because the information was no longer accurate information."

"The ABS data does not relate to actual consumption, which is why it is called apparent," adds Jimmy Louie, a lecturer in dietetics at Sydney University's school of molecular bioscience.

"Apparent consumption only tells you how much sugar is produced and exported, it doesn't take into account how much is eaten.

"There are always going to be limitations to the ABS data, which has now been acknowledged in the paper."

Wilson says it's not good enough.

"[To say sugar consumption is declining] is a very, very big statement to make," she says of the study, which was funded by sugar companies. "They probably, as scientists, should know better.

"The very source that they're basing it on has acknowledged that it's flawed."

Wilson argues that there is good motivation for saying consumption is declining.

There is a correlation between increasing sugar consumption and increased metabolic disease and WHO has amended its recommendations as a result of this.

"Obesity is increasing, sugar is going down, there must be some other cause," she says is the message of the study.

This is indeed what the authors claim.

"The downward trend in sugar consumption observed in our study is interesting because it runs counter to recent assumptions that sugar intake is rising and driving increasing rates of overweight and obesity in Australia. However, cause and effect conclusions can't be drawn from our study," Shrapnel says.

"Given the current attention being paid to sugar, we thought it was essential that healthcare professionals and policymakers had access to recent and accurate data on trends in sugar consumption. Informed policies can now be developed from such studies."

Bailes says even if the data was accurate, it's still too much.

She says "42 kilograms of sugar a year is still a lot".

"It's about 23 teaspoons a day, making up over 20 per cent of our energy intakes.

"The World Health Organisation recommends having 10 per cent of our energy from added sugar."

Louie says new, soon to be published data, based on the Australian Health Survey, indicates that sugar consumption levels in Australia have remained reasonably steady in the past 20 years.

"Our results indicate a slight decline in sugar among adolescents; adults are about the same," he says.

With obesity and health issues on the rise, where does this leave us?

"The public is very confused about what they're meant to eat ," Wilson says. "It's good if they're aware of the competing politics behind the scenes . . . and decide if the study is something they should take notice of."

Burrell says, data aside, it's about looking at consumption in context.

"Activity continues to decline which means we all need far less concentrated fuel sources so while sugar may have declined, it still may not have declined to the extent activity has and, hence, excess consumption remains an issue."