What would happen if everyone went vegan?
What would happen if every person on Earth adopted a vegan diet – without milk, meat, honey, or any animal-sourced food? It’s a hypothetical question, but environmental writer Paul Allen argues that it's more relevant than ever
The idea of everyone adopting a vegan diet might sound extreme, but in the last few years, the number of Britons following a plant-based diet has risen significantly. There are at least 600,000 vegans in the UK — although some sources put this figure nearer 2.7 million — while nearly 40 per cent of meat eaters say they've reduced the amount of meat they consume.
You can see this growing interest in vegetarianism and vegan diets all around us. From the explosion of dairy-free ‘milk’ alternatives on supermarket shelves to vegan options on menus – or even entirely vegan restaurants. What was once a more niche lifestyle choice is becoming increasingly mainstream.
For scientists, policymakers and economists, the idea of a vegan future is especially interesting – with one of the biggest drivers being the environment.
To get you started, check out our top vegan recipes, including easy vegan dishes, vegan family recipes and vegan desserts.
How does food affect greenhouse gases?
Your fridge might seem an unlikely setting for the fight against global warming, but did you know that food is responsible for a third of all manmade greenhouse gas emissions? What’s more, meat and dairy make up nearly 60 per cent of that carbon footprint.
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The UN says that global farmed livestock accounts for roughly 11 per cent of all manmade greenhouse gas emissions (with methane from cows a surprisingly big culprit). But according to new research published in the journal Climate, if we all went vegan, the world’s food-related CO2 emissions may drop by 68 per cent within 15 years, The move, which the study’s authors admit is hypothetical, would also provide the cut in emissions needed to limit global warming to 2ºC.
However, going vegan is not the only way to reduce food-related greenhouse gasses. Regenerative farming improves soil health on a farm by diversifying the types of crops grown and integrating them with animals. For example, a farmer could graze cows or sheep on a field for one year, making use of their natural fertiliser while also giving the soil a rest.
The Soil Association says healthy soil can capture and store more carbon than degraded soil; around two tonnes more carbon in every football pitch-sized patch of farmland. The idea is gaining popularity – in 2021, the UK government announced plans to subsidise farmers up to £70 per hectare if they adopt regenerative agriculture techniques.
So, going vegan may be better for the planet but there are other ways to tackle carbon emissions and global warming that don’t mean cutting out meat and dairy.
Is a vegan diet healthy?
We know Western diets are linked to many health problems including heart disease, diabetes and obesity. In 2015, the World Health Organisation even categorised processed meat such as bacon as carcinogenic, along with asbestos, alcohol and arsenic. This might suggest that switching to a more plant-focused diet may be good for you as well as the planet.
An increasing amount of evidence shows the health benefits of eating more plant-focused foods, such as a reduced risk of dying from heart disease, fewer cases of type 2 diabetes and a lower risk of some cancers. A 2018 study by University of Oxford even concluded that switching to a plant-based diet could save up to eight million lives worldwide.
However, being vegan doesn’t necessarily mean you’re eating healthily. Some vegan products contain a lot of coconut oil, for example, which is high in saturated fat. The rise in vegan junk food, like burgers, ‘fish’ and chips, or sausage rolls, could also be fooling you into believing these foods are healthy. In fact, many are high in calories but lacking in essential nutrients, or are packed with salt and sugar.
Vegan diets may also miss out on vital vitamins and minerals, as they’re naturally low in calcium, vitamin D, iron, vitamin B12, zinc and omega-3 fatty acids. If you are vegan, it’s important to eat plenty of plant proteins from beans, lentils, chickpeas, tofu, and soya versions of ‘milk’ and yogurt to help boost your intake of those nutrients.
Peanuts are also a good vegan source of protein, while other nuts and seeds can provide minerals such as zinc and selenium – cashews, pistachios, flaxseeds, chia or pumpkin seeds are particularly valuable. Quinoa and buckwheat are often called pseudo-grains but are in fact seeds; quinoa is especially useful for vegans because it contains all of the 9 essential amino acids that we need for growth and repair.
It’s easy to follow a balanced diet as a vegan but you need to be aware of what – and how much – you’re eating: good advice for omnivores and herbivores alike.
Can going vegan reduce food shortages?
Would a vegan future make food poverty history? If it’s about freeing up space and resources for growing food, there is some evidence to back this up.
A meat-eater’s diet requires 17 times more land, 14 times more water and 10 times more energy than a vegetarian’s, according to research published in The American Journal of Clinical Nutrition. This is principally because we use a large proportion of the world’s land for growing crops to feed livestock instead of humans – of the world’s approximately five billion hectares of agricultural land, 77 per cent is used for livestock.
This squeeze on resources is only set to intensify. In 50 years, the UN predicts there will be 10.5 billion people on the planet (the current world population is around 8 billion). To feed us all, we need to grow food more sustainably.
One of the counterarguments against this vegan solution is that some grazing land isn’t suitable for growing crops. That’s certainly true, but there’s actually a bigger problem with eradicating world hunger. Right now, we already produce enough calories to comfortably feed everyone on the planet, but more than 820 million people may still not get enough food.
In other words, having enough to eat is as much about politics and big business as it is about dietary choices, so there’s nothing to say that hunger would be a thing of the past in a vegan world.
Where would all the animals go?
If we no longer bred farm animals, what would happen? Would they become extinct? Would they overrun the planet?
Billions of farm animals would no longer be destined for our dinner plates and if we couldn’t return them to the wild, they might be slaughtered, abandoned, or taken care of in sanctuaries. Or, more realistically, farmers might slow down breeding as demand for meat falls.
Farm animals are bred far more intensively than they reproduce in the wild. As with all wildlife, any returned animal populations would fluctuate and eventually reach a balance, depending on predators and available resources in the wild.
It’s worth noting that not all livestock could simply ‘go free’. Some farm breeds, such as broiler chickens, are now so far removed from their ancestors that they couldn’t survive in the wild. Others, like pigs and sheep, could feasibly return to woodlands and grazing pastures, and find their own natural population levels.
On top of that, even if we stopped eating animals, our ongoing destruction of wild habitats would still reduce their numbers. As always with nature, it’s a question of balance.
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For more on vegan diets, we've collaborated with BBC Future – read the BBC Future guide to the health benefits of going vegan.
Paul Allen is author of The Ethical Careers Guide and founder of creative agency Lark.
All health content on goodfood.com is provided for general information only, and should not be treated as a substitute for the medical advice of your own doctor or any other health care professional. If you have any concerns about your general health, you should contact your local health care provider. See our website terms and conditions for more information.
