Making junk food more expensive could improve the health of Kiwis - study

Making food high in fat, salt and sugar more expensive and fruit and vegetables cheaper will improve Kiwis' health.

Those are the findings from new research into how people's purchasing behaviour changes when the price of supermarket items change.

More than a thousand Kiwis shopped in a virtual supermarket as part of the study buying their weekly groceries.

And like the shop, the prices of some of the food weren't real.

"We wanted to test the effects of a range of food taxes and subsidises and understand what effect they have on our overall shopping patterns," said Auckland University professor of population nutrition Cliona Ni Mhurchu

Taxes were placed on sweetened drinks, fatty foods, salty foods, and sugary foods while subsidies were put on fruit and vegetables.

In some cases, they found people would substitute unhealthy foods for other unhealthy foods.

"It might be that although they're not buying a product high in salt, for whatever reason they've substituted it for something with more sugar than they'd normally buy," said Mhurchu.

But the researchers found the combined effect of the taxes was positive.

"The overall healthiness of the shopping basket improved significantly," she continued.

The study recommends introducing a so-called "junk food tax" which would target foods high in saturated fat, salt, and added sugar, making them about 10 percent more expensive.

The research shows if fruit and vegetables are cheaper, people are more likely to buy them or simply just give them a go.

"That slight change over a whole population has major health benefits and can actually lead to major savings for the healthcare system as well," said Mhurchu.

Health Minister David Clark says he's interested in this research but the Government won't be able to push it through.

"We've been very clear as a government that we will be introducing no new taxes so the answer to that is no," he said.

Meaning this virtual shopping trip is still a long way from reality.