DHBs want a tax on sugary drinks - warning the obesity epidemic could result in Kiwi kids living shorter lives than their parents.
The extraordinary letters sent to Health Minister David Clark are the strongest call for change so far from within a health system treating more obesity-related disease and tooth decay.
"For the first time in history, NZ children could live shorter lives than their parents as a result of excess weight and obesity," Andrew Blair, chair of both Capital & Coast and Hutt Valley DHBs, told Clark.
Pacific, Māori and people living in the poorest areas bore the burden of an obesity problem causing "spiralling demands and rising costs", Blair wrote.
"We understand the difficulties with various lobby groups in this highly contentious space and would encourage you to be as proactive as possible, particularly in relation to sugar-sweetened beverages, including consideration of the introduction of a tax.
"Your commitment to school-based clinics and ensuring the strength of our health services will also assist us to support healthy communities and families. This would be more effective when the environment supports fewer unnecessary sugar-sweetened beverages and energy drinks."
The DHBs cited the World Health Organisation (WHO) position that there is clear evidence that taxes and subsidies influence buying behaviour, and this could curb consumption of sugar-sweetened drinks and help in the fight against obesity and diabetes. A tax was also supported by the NZ Dental Association and the Australian Medical Association.
Clark was urged to swiftly introduce a tax, and strongly consider including artificially-sweetened drinks because they are also harmful to oral health.
Blair was not available for interview. Of the country's other 18 DHBs that responded to a request for comment, Nelson-Marlborough DHB confirmed it supports a 20 per cent excise tax on sugar-sweetened beverages.
Auckland's three DHBs are members of the Healthy Auckland Together coalition. Its spokesman Dr Michael Hale said the DHBs hadn't developed a position on a sugary drinks tax, however the coalition "would like to draw attention to the statements of WHO, the Australian Medical Association and our dental colleagues and partners about this intervention".
Only one DHB confirmed it had previously asked the Government to consider a sugar tax. In 2015 Hauora Tairāwhiti wrote to former Health Minister Jonathan Coleman and asked him to consider a tax, with chair David Scott saying nearly 40 per cent of the DHB's population were obese and "this disease creation villain should be restricted at source".
"We have the highest proportion of child teeth extraction in the country which is sadly directly related to babies and toddlers being fed sugary drinks initially via a baby's bottle," Scott wrote.
Clark was unavailable for interview, but said in a statement the Government had no immediate plans for a tax on sugary foods or drinks.
"We pledged to the public we wouldn't introduce any new taxes in our first term. Instead, we are looking at ways to reduce the amount of sugar in processed food and drink and to develop a better labelling system."
Clark said he had met with the food industry and they were clear about his concerns about the obesity epidemic and his desire to see less sugar in our foods.
"It's clear from those meetings that some businesses are already progressing a move to low sugar products. They're doing it overseas, they know what that looks like and they would like to see the world moving faster in that direction."
A Ministry of Health-commissioned report delivered in October 2017 concluded evidence for a sugar tax was inconclusive. Think-tank the New Zealand Initiative and other opponents of a tax argue studies relied upon by tax advocates vastly overestimate how much taxes would reduce consumption.
Sir Peter Gluckman, until recently the Prime Minister's Chief Science Advisor, told RNZ last month that the evidence for a sugar tax in countries like New Zealand had become much stronger in recent years. A report to Prime Minister Jacinda Ardern had outlined that change.
Former Prime Minister Helen Clark has called for a sugar tax and says lobbying efforts against such measures are "reminiscent of the way the tobacco industry fought tax and regulation".
The NZ Beverage Council, which represents manufacturers, could not be reached for comment.