New Zealand should tighten rules and halt the advertising of unhealthy foods to children in a bid to tackle obesity, researchers say.

The University of Auckland team checked a database of 13,066 packaged foods and found that more were considered "healthier" options under New Zealand's Health Star Rating (HSR) system than under the World Health Organisation's (WHO) criteria for foods that can be promoted to children.

Three and a half stars or more on the 5-star scale can be considered "healthier", they say. Overall, 36 per cent of the foods were in that category, while only 29 per cent qualified as "permitted" by the WHO for advertising to children.

The disparity was much greater for many sweet foods, such as 12 per cent of biscuits in the star system versus 0.3 per cent for the WHO; 77 versus 34 per cent of breakfast cereals; and 44 versus 1 per cent of dried fruits. The Health Ministry's food and beverage classification system (FBCS) was also looser than the WHO's.


"The HSR and FBCS systems would permit marketing of a number of food products of concern, particularly high-sugar breakfast cereals, fruit juices and ready meals," say Professor Cliona Ni Mhurchu and colleagues, reporting their findings in today's NZ Medical Journal.

They conducted the study to inform the Advertising Standards Authority's review of the code of advertising food to children. They recommend using the WHO system.

"Given the recognised weak nutritional standards employed by industry for defining healthy foods and because many child-oriented food marketers do not participate in self-regulation, the new children's code ... should be [independently evaluated].

"If the revised voluntary code still proves ineffective in reducing New Zealand children's exposure to the marketing of unhealthy foods and drinks, additional policy and regulatory actions will be necessary."

The voluntary Health Star Rating system was developed by the Government with the food industry.

The major food category differences between the three systems - in breakfast cereals, fruit bars, fruit/vegetable juices and dried fruit - "appear to be due mainly to the different weighting that each system gives to sugar, with HSR in particular ... more lenient in classifying more high sugar products as eligible."

Association of Advertisers chief executive Lindsay Mouat said the WHO criteria were deliberately high.

"Industry does not dismiss the WHO criteria out of hand but by WHO Geneva's own admission, they are 'tough and aspirational' which is why you don't see them being adopted.

"Critically, you cannot ask industry to reformulate their products, take out fat, salt and sugar and then forbid them from marketing the 'better-for-you' version, which is what the WHO classification does.

"We [all want to induce] behavioural change; that means slowly weaning consumers on to healthier options."

The Food and Grocery Council declined to comment on the research, referring the Herald to its submission on the code review, which says the code is working well.

The code reflects the "high standards for responsibility by the industry that ensure parents' and children's trust and protection for the benefit of all of the community".

The council advised reducing the age group to which the code applies to under 12, from under 14 at present.

Food Safety Minister Jo Goodhew defended the star-rating system.

She said: "The Health Star Ratings system was not designed as a tool to restrict marketing to children, but as a way for consumers to easily access nutritional information, compare similar packaged products, and to encourage producers to reformulate their products to support healthier food choices."