A new Otago University study has found 2 million Kiwis will be considered obese by 2038 if the obesity epidemic isn't curbed.
The research, published today in the Australian and New Zealand Journal of Public Health, shows the average body mass index (BMI) went from 26.4 to 28.3 between 1997 and 2015. At this rate, by the early 2030s it will cross over the obesity threshold of 30.
It's even worse for Māori and Pacific people, and those living in social deprived neighbourhoods. By 2038 the BMI of Pacific people is projected to exceed the general population by 7.1 to eight.
Researchers Ross Wilson and Haxby Abbott say changes need to be made to public health policy to address the situation.
"BMI and obesity rates are continuing to increase in New Zealand and our expectation is that they will continue to do so for the foreseeable future," Dr Wilson said.
"High BMI has now overtaken tobacco as the greatest contributor to health loss in New Zealand, which emphasises the public health importance of these findings."
The researchers said the forces behind the epidemic are largely the availability of high-energy, low nutrient foods and lower physical activity across all ages.
They say continued increases across the population will result in premature mortality, population health loss, increased healthcare system costs and workplace productivity losses.
Dr Wilson and Prof Haxby say changes to the cost of food and the promotion of more exercise is the best way to curb the epidemic.
"A comprehensive obesity reduction strategy might include, among other things, improving the relative affordability of healthy foods (eg, through taxation, subsidies), restrictions on marketing of unhealthy foods and promotion of active modes of travel such as walking and cycling," they said.