The Government is again rejecting calls for a 20 percent tax on fizzy soft drinks despite new international research showing price hikes cut consumption.
It is expected to announce policies before the end of the year to tackle childhood obesity.
Campaigners said the Government had been slow to act, and they were calling for much tougher measures to fight the growing crisis that is projected to overtake smoking as the leading risk to health next year.
Anti-sugar groups said all schools should ban fizzy drinks. They wanted the reintroduction of the healthy food in schools rules, which were scrapped by the National-led government in 2009. They also called for tougher controls on junk food marketing, and a 20 percent tax on fizzy drinks.
Health Minister Jonathan Coleman told TVNZ's Q & A programme yesterday there was no evidence a sugar tax worked, but Auckland University health researcher Gerhard Sondburn said a new study from Mexico was too powerful to ignore.
"They've implemented a 10 percent tax and got a 12 percent reduction in consumption and in the poorer segments of society a 10 percent tax resulted in a 17 percent reduction in sugary drink intake," he said.
Seventeen-year-old Alexandra Mareko used to drink a bottle of Coca-Cola twice a day.
"I would buy a fizzy drink in the morning before school, drink it before school and also after school I would purchase a new bottle of fizzy drink."
But when her school, Kelston Girls College in West Auckland, cracked down on sugary fizzy drinks with the warning that every 600 millilitre bottle contained 16 teaspoons of sugar, she cut her habit.
"Seeing the physical amount that was put in the fizzy drinks really got to me, and just the effects of the sugar like obesity and tooth decay, because I love my teeth and I don't want anything to go wrong."
Alexandra Mareko said the effects were instant.
"In the morning I used to be really grumpy, off task, you know - always backchatting to the teachers and now I'm just, when I come to school I'm a lot calmer and I can get in the classroom, do my work and go straight into it rather than just mucking around and going off task."
NZ third fattest
A 2009 Organisation for Economic Co-operation and Development (OECD) report ranked New Zealand the third fattest among that group of industrialised nations, and obesity is now estimated to cost the country $1 billion a year.
The New Zealand Health Survey 2012/13 showed one in three New Zealand adults were obese, with the rate rising sharply among Māori and Pacific people.
The survey said one in nine children were obese, rising to one in five for Maori and more than a quarter of Pacific children.
Louisa Ryan, who heads Pacific Heartbeat at the Heart Foundation, said she wanted an urgent, nationwide action plan.
"We are at crisis point. If you were to go into the renal clinic unit at, say, Middlemore Hospital where there's a high Maori / Pacific population, 80 percent of the patients in those renal dialysis chairs are Maori and Pacific. Renal failure is the result of uncontrolled chronic diabetes which started off at the beginning with obesity," she said.
AUT's Professor of Nutrition Elaine Rush said regulation alone would not reduce waistlines.
She called for a nationwide roll out of the primary school based obesity control programme Project Energize started by Waikato DHB 10 years ago, where so-called "energizers" work with schools, teachers and parents on a health and fitness programme.
Ms Rush said a national scheme would cost $45 a child, or $20 million a year.
"That's the grassroots or the bottom-up way of doing things, and then you need the top down regulation and control. I think the time has come for New Zealanders to stand up and say our future children are the most important thing for us so we've got to invest in them."
Mr Coleman said tackling obesity was a top priority but further regulation was not needed.
He said he wanted to focus on excercise, portion control and the diets of pregnant women.