Sweet tooth a fatal flaw
It won't be welcomed by sweet-toothed new Zealanders, but research has shown how a diet high in sugar can cause health damage even when a person is not overweight.
Signs of impaired heart functioning were seen in mice that were fed a sugar-rich for just 12 weeks, as part of a study conducted at the University of Melbourne.
The mice ate the equivalent of a high-sugar diet for humans - for example a teenager fuelled by soft drinks and lollies - and the damage was seen to unfold even though they maintained a normal weight.
PhD candidate Kimberley Mellor said the results pointed to commonly held misconceptions about healthy eating, and an "overlooked" potential driver in the steady rise of type 2 diabetes.
"It has been overlooked but now it is increasingly moving to the forefront of this debate," Ms Mellor said.
"... Because we are recognising that it is not just fat that is bad for us, it is sugar as well.
"And all of these foods that we think of as healthy because they are low fat are actually not, because of their high sugar content."
The mice were fed food high in fructose - the substance that gives sugar its sweet taste - which is a common food additive particularly in the form of high-fructose corn syrup.
The mice showed signs of oxidative stress in their hearts, which leads to a breakdown of cardiac cells and a disruption of the way these cells react to calcium, an essential process which enables the heart to beat.
While the study looked for an impact on heart function, Ms Mellor said other research also pointed to a link between a high-fructose diet and the onset of diabetes.
There had been a "dramatic shift" in the amount of fructose in the food supply over the past 30 years, she said, with average consumption thought to be up by about 30 per cent.
"Fructose intake has increased so much over the last few decades and this has been in line with an increase in type 2 diabetes," Ms Mellor said.
"There has been a view that diabetes is involved with obesity, but actually we know that many diabetics are not obese and some are not even overweight.
"This research ... is important because it shows us what can happen independent of body weight changes."
The take home message, Ms Mellor said, was to "cut out sugar as much as possible" from the diet and there was little point switching to low fat foods that were otherwise high in sugar.
"It really puts forward a case for restricting the amount of fructose that can go into foods, because at the moment there are no restrictions at all," Ms Mellor also said.
The research was done under the supervision of Professor Lea Delbridge and the results were presented at the 5th Australian Health and Medical Research Congress, which is underway in Melbourne this week.