Imposing the same strict restrictions on unhealthy food and drink as tobacco will curb the country's obesity scourge, an Otago University researcher says.

Professor of Marketing Janet Hoek said restricting advertising, increasing tax, adding warning labels and using plain packaging were all ways to encourage people to look for healthier food options.

"I would begin with carbonated soft drinks as these offer no nutritional benefit at all," she said.

The restrictions that had been placed on tobacco had been effective in stemming the number of smokers, Prof Hoek said.


About 20 years ago about 30 per cent of New Zealanders smoked. This dropped to nearly 23 per cent in 2002/03, decreasing further in 2006/07 to just under 20 per cent, and last year the number of smokers had lowered again to about 17 per cent, according to the NZ Health Survey by the Ministry of Health.

"Tobacco is a very unambiguous product because it is uniquely harmful - some foods are closely analogous to tobacco as they offer no nutritional benefit and the research evidence suggests changes in food supply, particularly the widespread availability of inexpensive, palatable, energy dense food have contributed to, if not at least partly caused, the rising prevalence of obesity.

"At the same time as tobacco has become more expensive, less visible and less socially acceptable, energy-dense and nutrient-poor foods have become less expensive, increasingly pervasive, and more convenient to access."

The number of tobacco users had dropped by about half since policies to restrict the way it was marketed came into place, Prof Hoek said.

"It makes sense to examine the potential these policies could have in reducing consumption of foods associated with obesity."

A recent study in the American Journal of Health found that soft drink consumption was significantly linked to overweight, obesity and diabetes worldwide, she said.

Prof Hoek pointed to a policy statement made by the American Academy of Pediatrics concluded that media clearly played an important role in the current epidemic of childhood and adolescent obesity.

Strategies by the food industry had challenged research supporting restrictions on food marketing, promoting more effective food labelling and questioning industry solutions had much in common with tactics used by the tobacco industry to delay government regulation, Prof Hoek said.