We know that meat has a huge impact on the planet and that vegan diets are more environmentally sustainable. But how exactly does the food we eat affect environmental outcomes and what difference does a plant-based diet make compared to a meat-heavy or even 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 foods. We found that vegetarians only have 30% of the dietary environmental impact of eating meat.
Nutritional data comes from specialty Study on cancer and nutrition which has been monitoring the same people (about 57,000 across the UK) for more than two decades. Those in our study reported what they ate and drank over the course of 12 months, and then we categorized them into six different groups: vegetarians, vegans, fish eaters and low, medium and high meat eaters based on their reported eating habits.
We then linked their nutritional reports to a data set containing information on the environmental impact of 57,000 foods. Crucially, the dataset takes into account how and where the food is produced – for example, carrots grown in a greenhouse in Spain will have a different effect than those grown in a field in the UK. This builds on previous studies, which tend to assume that, for example, all bread, all steak, or all lasagna have the same environmental impact.
By incorporating more details and nuances, we were able to establish 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 carnivore diet. In other words, consideration of the region of origin and methods of food production does not obscure differences in environmental influences between food groups.
Vegetarians vs. Carnivores
Unsurprisingly, diets containing more animal foods have greater environmental impacts. Per unit of food consumed, meat and dairy products have three to 100 times the environmental impact of plant foods.
This can mean huge differences between the two extremes, vegetarians and meat eaters. Vegetarians in our study had only 25% of the dietary impact of heavy meat eaters in terms of greenhouse gas emissions, for example. That’s because meat uses more land, which means more deforestation and less carbon stored in trees. A lot of fertilizers (usually made from fossil fuels) are used to feed plants that feed animals. And because cows and other animals emit gases directly.
It’s not just emissions. Compared to heavy meat eaters, vegetarians also had only a 25% dietary impact of land use, 46% of water use, 27% of water pollution and 34% of biodiversity.
Even low-meat diets only had about 70% of the impact on most environmental measures of high-meat diets. This is important: You don’t have to be completely vegan or even vegan to make a huge difference.
global impact
These findings are crucial as the food system is estimated to be responsible for approximately 30% of global greenhouse gas emissions, 70% of freshwater use globally, and 78% of freshwater pollution. on Three-quarters of the world’s land is free of ice It has been affected by human use, especially for agriculture, and land use change such as deforestation, which is a major source of biodiversity loss.
In the UK, meat consumption decreased in the decade through 2018but to achieve environmental targets, the UK National Food Strategy and Climate Change Committee recommend a further reduction of 30-35%.
The choices we make about what we eat are personal. They are deeply ingrained habits that are hard to change. But our study and others continue to consolidate evidence that diet has huge global environmental and health impacts that can be reduced by transitioning to more plant-based diets. We hope our work will encourage policymakers to take action and people to make more sustainable choices while still eating something nutritious, cheap and delicious.
(Michael Clarke – Postdoctoral Researcher, Oxford Martin Program on the Future of Food, University of Oxford -, Keren Baber – Senior Nutrition Epidemiologist, University of Oxford – in conversation 7/21/2023)
assembly no receives and against public funding (also 5 per thousand)
Its economic strength is the inscriptions and contributions donated by those who deem it useful
Donate now
“Devoted bacon guru. Award-winning explorer. Internet junkie. Web lover.”
