A new study investigating how certain refined sugars affect type two diabetes could be the first of its kind.
More than 250,000 New Zealanders have the disease, with a high proportion suffering heart failure.
Auckland University researchers are looking at the effect of a high fructose diet on heart health.
Fructose is found naturally in fruit and vegetables but can be added to other foods as a sweetener.
Dr Kimberley Mellor is leading the study and said rates of diabetes and deaths from complications were rising dramatically, particularly among Māori.
Dr Mellor said more than 80 percent of people with type two diabetes would suffer heart failure.
She said heart abnormalities in diabetes patients were distinctive and specific treatment was not available.
It was the first study to focus on how fructose contributed to heart muscle damage, she said.