June 24, 2024

Oxford Scientists Confirm Vegan Diet Is Much Better for the Planet : ScienceAlert

We know that meat has a significant impact on the planet, and that plant-based diets are more environmentally sustainable.

But just how much of an impact does the food we eat have on environmental outcomes and what difference would following a vegan diet make compared to a high meat diet, or even a low meat diet?

We studied the dietary data of 55,000 people and linked what they ate or drank to five key measures: greenhouse gas emissions, land use, water use, water pollution and biodiversity loss.

Our results are now published in Nature’s Food. We found that vegans have only 30% of the environmental impact of the diet of high-meat eaters.

The dietary data came from a large study cancer and nutrition that has been tracking the same people (about 57,000 in total across the UK) for over twenty years.

The people who participated in our study reported what they ate and drank over 12 months and then we classified them into six different groups: vegan, vegetarian, fish eaters, and low-, medium-, and high-meat-eaters based on their self-reported diet.

We then linked their diet reports to a dataset containing information on the environmental impact of 57,000 foods. It is vital that the data set takes into account how and where food is produced – carrots grown in a greenhouse in Spain will have a different impact than those grown in a field in the UK, for example.

This builds on past studies, which assume for example that all types of bread or steak or lasagna have the same environmental impact.

By incorporating more detail and nuance, we were able to show with greater certainty that different diets have different environmental impacts.

We found that even the least sustainable vegan diet was still more environmentally friendly than the most sustainable meat eater diet. In other words, accounting for region of origin and methods of food production does not hide the differences in environmental consequences between dietary groups.

Vegans vs meat eaters

Not surprisingly, diets containing more animal-based foods had higher environmental impacts. Per unit of food consumed, plant-based foods have between 3 and 100 times more impact on the environment.

This can mean big differences between the two extremes, vegans and high meat eaters. Vegans in our study, for example, had only 25% of the dietary impact of high meat eaters in terms of greenhouse gas emissions.

That’s because meat uses more land, which means more deforestation and less carbon stored in trees. It uses a lot of fertilizers (usually produced from fossil fuels) to feed the plants that feed the animals. And because cows and other animals pass gas directly themselves.

It’s not just emissions. Compared to the number of high meat eaters, vegans had only 25% of the dietary impact on land use, 46% on water use, 27% on water pollution and 34% on biodiversity.

High-meat diets had only about 70% of the impact across most environmental measures over even low-meat diets. This is important: you don’t have to be fully vegan or even vegetarian to make a big difference.

Global influence

These findings are critical because the food system is estimated to be responsible for approximately 30% of global greenhouse gas emissions, 70% of the world’s freshwater use and 78% of freshwater pollution.

Around three quarters of the world’s land without ice impact of human use, mainly for agriculture and land use change such as deforestation which is a major source of biodiversity loss.

In the UK, eat meat decrease over the decade to 2018but to meet environmental targets the UK’s National Food Strategy and Climate Change Committee recommend a further reduction of 30%-35%.

The choices we make about what we eat are personal choices. They are very ingrained habits that can be difficult to change. But our study and others continue to corroborate evidence that the food system has a huge global impact on the environment and health that could be reduced by shifting towards plant-based diets.

We hope that our work can inspire policy makers to take action and encourage people to make more sustainable choices while still eating something nutritious, affordable and tasty.

Michael O’ClairigPostdoctoral Researcher, Oxford Martin Program on the Future of Food, University of Oxford and Turn PaperSenior Nutrition Epidemiologist, University of Oxford

This article is republished from The conversation under a Creative Commons license. Read the original article.

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