Slicing goods and services tax off "healthier" foods led supermarket shoppers to buy 11 per cent more of those items in a university-led trial.
Top of the list were fruit and vegetables, at two-thirds of the increase.
The large trial of shoppers by Auckland University was done before GST was increased to 15 per cent, when it was 12.5 per cent.
No one knows if these suddenly "healthier" shoppers ate better as a result - they bought just as much of everything else - but the trial produced excitement that at last an intervention aimed at improving poor nutrition might work.
The average household spent $178 a week on food in 2009/10, including $20 on fruit and veg. At 12.5 per cent, their GST component was $2.22.