Nutritionists are criticising a star-rating system set to be introduced to New Zealand in a bid to help shoppers make healthy food choices.
Minister for Food Safety Nikki Kaye announced on Friday that New Zealand would adopt the healthy star rating system used in Australia, but on a voluntary basis.
But the proposal has been met with scepticism from food experts and nutritionists, who say it is not the best option to help consumers, and criticised the Government for ignoring research on what works best.
Researcher Dr Ninya Maubach, from the University of Otago's department of marketing, who led a study that compared star ratings, daily intake guides, and traffic light labels, said the findings showed most people could identify healthy products using either the stars or traffic light systems.
"However, a traffic light label appears much more likely to help people distinguish less healthy choices. If we want to use labels to reduce obesity, we need a label that promotes quick identification of unhealthy products."
She also rubbished Australia's decision to reject the traffic light system.
"Politicians rejected an expert panel's recommendation to support the multiple traffic light format on grounds of insufficient evidence, despite many published studies demonstrating its effectiveness, yet there is no peer-reviewed research into this new format."
Dr Rachael McLean, senior lecturer public health and nutrition at the University of Otago, said a 2011 review recommended the adoption of the traffic light system as "the option that has been shown in multiple studies to be most effective in communicating messages about nutrition to a wide range of consumers".
"By contrast, the food industry has promoted the daily intake labelling scheme, which is incorporated into the health star rating label.
"While it has been shown that under experimental conditions consumers are able to use the health star rating system to identify healthier food products, it is not clear how the system will operate in real world settings," she said.
"It is essential that the label is evaluated following its introduction to determine whether the presence of the label has an impact on consumer purchasing behaviour, as previous research suggests that consumers over-estimate their use of nutritional information and read information less than expected."
Professor Cliona Ni Mhurchu, programme leader for nutrition research at the National Institute for Health Innovation, University of Auckland, said: "Evidence shows that people struggle to use and understand our current back-of-pack nutrition information panels. Research has also shown that people can work out what foods are healthy or unhealthy more easily when using interpretive nutrition labels, for exampled the UK traffic light labels.
"Our New Zealand research found that all of our key population groups find interpretive nutrition labels easier to use and understand than numerical labels like NIP and the daily intake guide."