A tax on sugary drinks could be an effective way to encourage healthy diets and fight obesity, a Hawke's Bay principal says.

"A tax on that would be quite acceptable to be honest, we tax the heck out of petrol, we tax the heck out of just about everything else," said Taradale Primary School principal Marty Hantz.

"It would be lovely to actually see that the price of milk was a lot lower than the price of any carbonated sugar drink."

His comments follow calls for sugar-sweetened beverages to be regulated like tobacco as a first step to combating New Zealand's obesity epidemic. The ideas were presented at the recent Public Health Association Conference in New Plymouth.


Mr Hantz said his school only encountered about one incident a year of a child bringing fizzy drink to school.

"Generally the teachers will confiscate that and just quietly talk to the parents and say, 'Look, that's not appropriate'."

He described the effect of high sugar intake in children as "birthday syndrome".

"You see a bunch of kids at a birthday party ... if they're really not used to drinking loads of fizzy drinks or [eating] loads of lollies ... they tend to be a lot more hyperactive - it's almost like they go a lot faster.

"If we ever had that in the schools it would make teaching that much harder again because the kids aren't necessarily more focused if they're drinking sugary drinks."

Gerhard Sundborn, from Auckland University, has proposed an 'end-game' strategy for sugar-sweetened beverages (SSBs) in New Zealand.

Based on the current tobacco end-game, which aims to see New Zealand smokefree by 2025, the SSB equivalent would see a heavy decrease in the amount of sugar Kiwis consume in drinks.

"There's no denying obesity has become an epidemic. By regulating the sugar content in beverages we'll be taking the first step to combating this global health problem."

Dr Sundborn said current initiatives to tackle obesity had proven ineffective, and data suggested our sugar intake was growing. "Just like tobacco, evidence also suggests many New Zealanders are addicted to sugar. People coming off a high sugar diet can often experience withdrawal symptoms, which is another reason these drinks need to be regulated."

The end-game strategy would see a reduction in SSBs in favour of artificially sweetened beverages, which aren't as detrimental to health. In time, these too would decrease in favour of healthier unsweetened drinks like water and milk.

Other suggestions include healthy vending machine policies and a tax on sugary drinks.

New Zealand Nutrition Foundation dietician Sarah Hanrahan said sugar was an emerging issue. Interventions such as taxing SSBs were worth considering.

"They have empty calories, they're not contributing anything else of nutritional value which makes them easier to isolate as a high sugar area where perhaps you could intervene.

"You'd need a whole lot more evidence to show it would be effective but absolutely it's a strategy worth pursuing."