Otago University Professor of nutrition Jim Mann is backing a warning about obesity in a report published in the United States.
The Commonwealth Fund report analysed health spending in 13 industrialised countries, including New Zealand.
The report says the US spends by far the most on health, but the quality of care varies and it is not better than in less expensive systems.
It says the prevalence of obesity in New Zealand is rising sharply and suggests that will push up health spending.
Professor Mann says the increase in obesity has been steep and incredibly rapid over the past 10 -15 years and a comprehensive plan is needed to tackle it.