Can taxes control the environmental costs of obesity?

It's widely known that New Zealand is one of the fattest nations in the world, but new research has highlighted its detrimental effects on the environment. The University of Oregon report says factors like sprawl and transportation policy affect obesity rates. And consumption of energy-dense foods made from corn and soy, including meat, increases soil erosion and water pollution from fertiliser use. Kathryn Ryan speaks with Professor Roberta Mann about how the epidemic has led to increased carbon emissions and how it has exacerbated climate change.