A bag of Homebrand potato chips is $1.50, and a litre of soft drink is $0.90.

For many families, the choice is obvious. Why get a bag of vegetables, when you could get 10 bags of chips or 16 litres of fizzy?

The cost of food increased by 8.3 percent since last August, according to Stats NZ's food price index.

Auckland University of Technology emeritus professor of nutrition Elaine Rush said the issue was a compounding disaster.

"It's not just food that's going up, it's petrol, and mortgages," she said. "Other influences, such as climate change and the war in Ukraine are affecting our food supply. It could be the beginning of a downward spiral." Read more