Call to make health star ratings essential on all products
The star rating system was introduced 10 years ago and is free to join, but as it's optional, products with a lower rating tend not to display their rank.
Public health groups want the Australian and New Zealand governments to get on with mandating health star ratings on food products.
The rating system on food and drinks is a joint initiative, overseen by the food ministers in both Australia and New Zealand.
Food manufacturers have been given until mid-November to achieve a voluntary uptake target of 70 percent, but they are not on track to meet it.
The George Institute for Global Health Food Governance program lead Dr Alexandra Jones said a review in 2019 found the system worked well and consumers understood and used it, but it needed to be used on more products.
It did not currently take into account whether foods were ultra-processed, but it was something it was watching closely, with the Australian government considering it through the Australian Dietary Guideline Review.
Jones said because the scheme was voluntary, it was more commonly found on high scoring products.
"What people are seeing is a very skewed version of the system because they're missing all the low scores."
Research from the institute found a 60 percent uptake among five-star rated products, compared to just 16 percent of products that would score half a star if displayed.
Only 24 percent of products that scored three stars or lower were currently displaying ratings.
Jones said the experience mandating country-of-origin labelling in Australia showed that widespread and rapid food labelling change could be achieved when required by law.
Dr Alexandra Jones says there is no reason for such high levels of Vitamin B6 as there are in some energy drinks.
ABC News / Craig Hansen
The system was originally developed with input from public health, consumer groups, and the food industry and Jones said it was important that industry influence was removed from the process of determining the ratings, to further enhance trust in the system.
Uptake among manufacturers had plateaued in the last four years and Jones said she wanted to see a decision voted on the mandatory legislation by the end of next year.
"There is evidence that it's guiding consumers to better choices, also that industry is removing salt and sugar from products, for example, to avoid warning labels.
"So we're seeing benefits to the healthiness of the food supply overall, and benefits to consumer choices."
Research published in the Journal of the Royal Society of New Zealand in March found the health star rating system had resulted in minimal health gains for New Zealanders, with its impact limited by the voluntary nature of the scheme.
Led by Dr Cristina Cleghorn from the University of Otago, Wellington, the research assessed whether the rating system encouraged food manufacturers to reformulate products to gain better ratings.
Modelling indicated the scheme had led to small changes in people’s diets.
Cleghorn said the voluntary nature of the scheme limited its impact, as research showed only 30 percent of eligible foods displayed the ratings.
Co-researcher professor Cliona Ni Mhurchu from the University of Auckland said the research found if the New Zealand scheme was made mandatory, and the health star ratings were applied to all eligible products in the same food groups, the health gains resulting from reformulation would increase to 24,300 health-adjusted life years and there would be savings to the health system of $568 million.
"But the gains are still low, relative to other possible powerful policy interventions, such as a fruit and vegetable subsidy combined with a sugar tax," she said.
Dietitians Australia CEO Magriet Raxworthy said public education about how the system worked, alongside mandatory labelling, was critical.
She said people struggled to navigate food labels and the health star system was a simplified tool to help with that.
"Until it's mandatory, people will continue to struggle out there to understand how to make good choices.
"We know that consumers are facing continuous, conflicting health claims and if we overlay that with an ever-evolving and beautifully dynamic nutrition science, it sometimes is quite overwhelming."
