Almost 80 per cent of drinks in New Zealand supermarkets are sugary, swelling the nation's health risks and indicating that industry self-regulation is failing, according to University of Auckland researchers.

The study tracked drinks on New World, Four Square, Countdown and Pak‘nSave shelves in Auckland over the past seven years to evaluate whether significant changes were made in the availability, sugar content and serve size of non-alcoholic drinks.

The study, published in the international journal Public Health Nutrition, was led by Dr Teresa Gontijo de Castro and Dr Sally Mackay from the Department of Epidemiology and Biostatistics in the School of Population Health in the Faculty of Medical and Health Sciences.

The 80 per cent estimate applies to single-serve drinks, those marketed to be consumed at one sitting.

The research showed that over the seven years there was an increase in the availability of sugar-free and low sugar beverages and of 'craft' sugar-sweetened soft drinks such as kombucha. This increase explains some of the decline in total average sugar content for some beverage groups.

However, these changes were not meaningful, as in 2019 a significant number of New Zealand drinks (72.9%) would be subject to a 'sugar levy' if the United Kingdom's Soft Drinks Industry Levy was applied here, says Teresa.

'Over half the drinks had between six to 12 teaspoons of sugar per drink."

The research also showed that the availability of smaller-sized drinks fell between 2013 and 2019 – a concern because of the potential link between larger serving sizes and obesity. There were fewer drinks sized below 250 millilitres.

"Industry pledges are not working and the government needs to step in,” said Dr Mackay. ”Government measures are needed to if we are to achieve a meaningful reduction in sugar content and serving sizes of drinks.”

Sugar-sweetened beverages are the largest source of sugars in our children's diets, linked to weight gain, type 2 diabetes, coronary heart disease, and tooth decay, the research paper says.