Eating a vegan diet massively reduces the damage to the environment caused by food production, the most comprehensive analysis to date has concluded.
The research showed that vegan diets resulted in 75% less climate-heating emissions, water pollution and land use than diets in which more than 100g of meat a day was eaten. Vegan diets also cut the destruction of wildlife by 66% and water use by 54%, the study found.
The heavy impact of meat and dairy on the planet is well known, and people in rich nations will have to slash their meat consumption in order to end the climate crisis. But previous studies have used model diets and average values for the impact of each food type.
In contrast, the new study analysed the real diets of 55,000 people in the UK. It also used data from 38,000 farms in 119 countries to account for differences in the impact of particular foods that are produced in different ways and places. This significantly strengthens confidence in the conclusions.
However, it turned out that what was eaten was far more important in terms of environmental impacts than where and how it was produced. Previous research has shown that even the lowest-impact meat – organic pork – is responsible for eight times more climate damage than the highest-impact plant, oilseed.
The researchers said the UK should introduce policies to help people reduce the amount of meat they eat in order to meet the nation’s climate targets. Ministers have repeatedly said they will not tell people what to consume, despite the precedent of, for example, taxes on high-sugar drinks.
Prof Peter Scarborough at Oxford University, who led the research, published in the journal Nature Food, said: “Our dietary choices have a big impact on the planet. Cutting down the amount of meat and dairy in your diet can make a big difference to your dietary footprint.”
The global food system has a huge impact on the planet, emitting a third of the total greenhouse gas emissions driving global heating. It also uses 70% of the world’s freshwater and causes 80% of river and lake pollution. About 75% of the Earth’s land is used by humans, largely for farming, and the destruction of forests is the major cause of the huge losses in biodiversity.
Prof Neil Ward at the University of East Anglia said: “This is a significant set of findings. It scientifically reinforces the point made by the Climate Change Committee and the National Food Strategy over recent years that dietary shifts away from animal-based foods can make a major contribution to reducing the UK’s environmental footprint.”
The study also showed that low-meat diets – less than 50g a day – had half the impact of high-meat diets on greenhouse gas emissions, water pollution and land use. However, the differences between low-meat, pescetarian and vegetarian diets were relatively small.
Prof Richard Tiffin at the University of Reading said: “This study represents the most comprehensive attempt to link food consumption data to the data on the environmental impacts of food production.
“Encouraging high-meat-eaters to reduce meat consumption and encouraging vegetarians to become vegans should result in lower emissions,” he said. “However, it’s hard to justify changes to the diets of moderate omnivores on the basis of these results, other than to switch to a completely vegan diet.”
The researchers who conducted the new study said diets enabling global food production to be sustainable would mean people in rich nations “radically” reducing meat and dairy consumption.
They said other ways of reducing the environmental impact of the food system, such as new technology and cutting food waste, would not be enough.
The biggest difference seen in the study was for emissions of methane, a potent greenhouse gas produced by cattle and sheep, which were 93% lower for vegan diets compared with high-meat diets.
The UK Health Alliance on Climate Change recommended in 2020 that sustainable diets should be supported by mandatory environmental labelling on foods, regulation of promotions and taxation of high-carbon foods.
A government spokesperson said: “People should make their own decisions around the food they eat. Achieving the net-zero target is a priority, and whilst food choices can have an impact on greenhouse gas emissions, well-managed livestock also provide environmental benefits such as supporting biodiversity, protecting the character of the countryside, and generating important income for rural communities.”
The farming minister, Mark Spencer, said last week that he would like to see genetically modified cows that emit less methane.
