Eating more fruit and vegetables and cutting back on red and processed meat will make you healthier. That’s obvious enough. But as chickens and cows themselves eat food and burn off their own energy, meat is a also major driver of climate change. Going veggie can drastically reduce your carbon footprint.
This is all at a personal level. What about when you multiply such changes by 7 billion people, and factor in a growing population?
In our latest research, colleagues and I estimate that changes towards more plant-based diets in line with the WHO’s global dietary guidelines could avert 5m-8m deaths per year by 2050. This represents a 6-10% reduction in global mortality.
Food-related greenhouse gas emissions would also be cut by more than two thirds. In all, these dietary changes would have a value to society of more than US$1 trillion – even as much as US$30 trillion. That’s up to a tenth of the likely global GDP in 2050. Our results are published in the journal PNAS.
Future projections of diets paint a grim picture. Fruit and vegetable consumption is expected to increase, but so is red meat consumption and the amount of calories eaten in general. Of the 105 world regions included in our study, fewer than a third are on course to meet dietary recommendations.
A bigger population, eating a worse diet, means that by 2050 food-related GHG emissions will take up half of the “emissions budget” the world has for limiting global warming to less than 2℃.
To see how dietary changes could avert such a doom and gloom scenario, we constructed four alternative diets and analysed their health and environmental impacts: one reference scenario based on projections of diets in 2050; a scenario based on global dietary guidelines which includes minimum amounts of fruits and vegetables, and limits to the amount of red meat, sugar, and total calories; and two vegetarian scenarios, one including eggs and dairy (lacto-ovo vegetarian), and the other completely plant-based (vegan).
Millions of avoidable deaths
We found that adoption of global dietary guidelines could result in 5.1m avoided deaths per year in 2050. Vegetarian and vegan diets could result in 7.3m and 8.1m avoided deaths respectively. About half of this is thanks to eating less red meat. The other half comes thanks to eating more fruit and veg, along with a reduction in total energy intake (and the associated decreases in obesity).
There are huge regional variations. About two thirds of the health benefits of dietary change are projected to occur in developing countries, in particular in East Asia and South Asia. But high-income countries closely follow, and the per-person benefits in developed countries could actually be twice as large as those in developing countries, as their relatively more imbalanced diets leave greater room for improvement.
China would see the largest health benefits, with around 1.4m to 1.7m averted deaths per year. Cutting red meat and reducing general overconsumption would be the most important factor there and in other big beneficiaries such as the EU and the US. In India, however, up to a million deaths per year would be avoided largely thanks to eating more fruit and vegetables.
Russia and other Eastern European countries would see huge benefits per-person, in particular due to less red meat consumption. People in small island nations such as Mauritius and Trinidad and Tobago would benefit due to reduced obesity.
Vegans vs climate change?
We estimated that adopting global dietary guidelines would cut food-related emissions by 29%. But even this still wouldn’t be enough to reduce food-related greenhouse gas emissions in line with the overall cutbacks necessary to keep global temperature increases below 2°C.
To seriously fight climate change, more plant-based diets will be needed. Our analysis shows if the world went vegetarian that cut in food-related emissions would rise to 63%. And if everyone turned vegan? A huge 70%.
Celebrity vegan and vegetarians
Celebrity vegan and vegetarians
1/24 Ariana Grande, pop star
"I love animals more than I love most people, not kidding. But I am a firm believer in eating a full plant-based, whole food diet that can expand your life length and make you an all-round happier person."
2/24 Paul McCartney, musician
"I've been a vegetarian for a long time now and over the years I've seen how the attitudes have changed around the world, so I'm not surprised when I see new research that shows more and more people are increasingly adopting 'meat free eating'."
3/24 Ellen DeGeneres, TV Host
"It doesn't make [Thanksgiving] harder at all. It makes it easier on the turkeys, too. They get to live."
4/24 Morrissey, musician
"I see no difference between eating animals and paedophilia."
5/24 Bill Clinton, former president of the US
Dr Dean Ornish, Clinton's doctor, said: "I asked him, 'Why do you want to live longer?' and he said, 'I want to live long enough to walk my daughter down the aisle and to see my grandkids born and grow up.'"
6/24 Peter Dinklage, actor
Dinklage has been a vegetarian since childhood and featured in PETA's 'Face Your Food' film.
7/24 Russell Brand, comedian
"I'm now vegan, goodbye eggs, hello Ellen."
8/24 Ellie Goulding, singer
"I've got taxidermy, I've got animals.... deer and all sorts. But weirdly, I'm a vegetarian and I don't eat meat. I'm a walking contradiction."
9/24 Ellen Page, actor
Page was named as one of PETA's 'Sexiest Vegetarian Celebrities' in 2014.
10/24 Al Gore, American politician
"There are 10 vegan restaurants in Nashville now." Speaking about how he maintains his vegan diet in the city.
11/24 Tobey Maguire, actor
Maguire said he was a vegan and "stopped consuming any mind-altering substances" when he was 19.
12/24 Stella McCartney
On her website, McCartney said that "the decision not to use leather or fur is not just because I don’t eat animals or that I think that millions of animals each year shouldn’t be killed for the sake of fashion. It’s because I also believe in the connection between fur and leather and the environment. There’s a huge connection."
13/24 Woody Harrelson, actor
"I've always been relatively healthy except for my vices."
14/24 Jared Leto, actor and musician
"I'm pretty healthy... I've been that way for a long time - 20 solid years of eating vegetarian/vegan and taking care of myself. That probably helps the preservation process."
15/24 Jessica Chastain, actor
It was reported that the vegan actor bought her mother a vegan food truck.
AP Photo/Sony - Columbia Pictures, Jonathan Olley
16/24 Joaquin Phoenix, actor
Featuring a PETA advert to promote vegetarianism for Thanksgiving, he said: "Holidays can be murder on turkeys. Let's make this one for the birds."
17/24 Beyonce and Jay-Z
Beyonce announced her vegan diet in a heavily-promoted segment for Good Morning American in June 2015.
18/24 Kate Mara, actor
Mara told E! Online that she stayed fit and healthy by being a vegan.
19/24 Alanis Morissette, musician
"I'm predominantly vegan, which my friends hate because it's not monogamous; 80% is vegan; the other 20% is following what my body needs."
20/24 Alicia Silverstone, actor
Silverston has a blog called The Kind Life which discusses vegan and vegetarian food.
21/24 Kate Nash
"I became a vegetarian last September - I used to suffer from OCD and it got stuck in my head that if I didn't eat meat then my bunny rabbit, Fluffy, would survive a dangerous operation she had to have."
22/24 Jennifer Lopez, singer and actor
Lopez said that she recommended a vegan diet "because you wake up and feel great".
23/24 Mark Hoppus, member of Blink 182
Hoppus announced he was a vegan on Twitter.
24/24 Olivia Wilde, actor
"[Being vegan] is not always easy and accessible. But it's a way of life and makes me as a person feel really good and physically look better."
What’s it worth?
Dietary changes would have huge economic benefits, leading to savings of US$700-1,000 billion per year globally in healthcare, unpaid informal care and lost working days. The value that society places on the reduced risk of dying could even be as high as 9-13% of global GDP, or US$20-$30 trillion. Avoided climate change damages from reduced food-related greenhouse gas emissions could be as much as US$570 billion.
Putting a dollar value on good health and the environment is a sensitive issue. However, our results indicate that dietary changes could have large benefits to society, and the value of those benefits makes a strong case for healthier and more environmentally sustainable diets.
The scale of the task is clearly enormous. Fruit and vegetable production and consumption would need to more than double in Sub-Saharan Africa and South Asia just to meet global dietary recommendations, whereas red meat consumption would need to be halved globally, and cut by two thirds in richer countries. We’d also need to tackle the key problem of overconsumption. It’s a lot to chew on.