Food, emissions and you
If every adult in New Zealand adopted a vegan diet and minimised food waste, the emissions saved would equal about 60 per cent of emissions from cars and vans.
The finding appears in a new study by University of Otago researchers investigating the health and climate impacts of different diets. Published in Environmental Health Perspectives, it found if New Zealanders ate more plant-based foods and less meat the health system could save billions of dollars and there would be sizeable reductions in climate change-causing greenhouse gases.
The researchers developed a New Zealand-specific food database showing emissions associated with different products (taking into account everything from production to transport and refrigeration).
Consistent with international studies, it showed the climate impact of animal products, such as beef, lamb, processed meats and butter, was much higher than plantbased foods, such as legumes and vegetables. ‘‘We have known for a long time now that we need to change the way we live to avoid the worst impacts of climate change. This includes changing the way we eat, so that our children and grandchildren are actually able to eat in the future,’’ environmental health senior lecturer and study author Dr Alex Macmillan said.
Emissions associated with the ‘‘typical New Zealand adult’s diet’’ amounted to about 6.6 kilograms of carbon-dioxide equivalents a day, according to the study. More than a third of this came from meat, seafood and egg consumption, and another quarter from highly processed foods.
Using this as a baseline, the researchers modelled what would happen at a population level if adults moved to different diets ranging from just following
dietary guidelines set by the Ministry of Health (which many people don’t) through to following a vegan diet and minimising food wastage.
Steps in between included having just one plant-based meal a day, to following a pescatarian diet. At a minimum – just following the dietary guidelines – they found there would be a 4 per cent reduction in diet-related emissions through to a 42 per cent annual reduction for the waste-free vegan diet. Cost savings to the health system ranged from $14 billion to $20b over the lifetime of the current New Zealand population.
‘‘We could take a huge burden off the health system to the tune of tens of billions over our lifetime just by making quite modest changes towards more climatefriendly diets and healthier diets – those two things go really nicely hand-in-hand, which is really exciting for addressing climate change,’’ Macmillan said.
Lead researcher and Otago medical student Jono Drew said the global food system was driving both the climate crisis and the growing burden of chronic diseases such as cardiovascular disease, diabetes and cancer. The researchers had included multiple scenarios to show what was possible if people were willing to change what they ate.
At the most ambitious end, if every New Zealand adult consumed a vegan diet and avoided food wastage, emissions saved would be equivalent to a 59 per cent reduction in annual light passenger vehicle emissions, the study found.
Incorporating more plant-based foods combined with food waste minimisation was one of the most important ways individuals could reduce their personal climate footprint, the study said.
‘‘If we just got rid of that food waste, we could cut our dietary emissions as a population by a whole tenth,’’ Macmillan said.
She believed there was increasing demand for plant-based foods in New Zealand, and said there needed to be systemlevel changes to encourage more people to change their diet. Measures could include updating the dietary guidelines to include messages about climate-friendly diets, pricing strategies and labelling schemes.