Jordi Casamitjana, the author of the book “Ethical Vegan”, answers the question of what would happen if everyone became vegan, without using the typical answer “it will not happen overnight.” 

It’s kind of a classic. 

If you are a vegan and have done any vegan outreach as I have, you would have encountered vegan-deniers who constantly cast you anti-vegan clichés they may have learnt in their own echo chambers — as if they were contra-spells from your attempts to “recruit” them for what they fear may be a sort of cult. You know, the typical “where you get your protein from?” or “plants suffer too.” There is one, though, that has always intrigued me: “What would happen to all the animals if everyone became vegan?” 

If you have been vegan for a while, you will know how to answer it. Something like this: “It will not happen overnight. The more vegans there are the higher the reduction in demand of animal products, which will reduce the breeding of animals until the few remaining could be rescued and live in sanctuaries.” Often, you get this comeback: “there will not be enough room in sanctuaries for all the millions of animals abandoned by the farmers”. And then a back-and-forth exchange starts where the vegan tries to explain the concepts of “demand” and “non-breeding”, and the vegan-denier tries to explain the concepts of “born to be eaten” and “overcrowded sanctuaries”.

In the end, vegan-deniers deny veganism with all its supporting arguments, so they would not necessarily listen, and they are only interested in “scoring” some logical points in the discussion. And some vegan outreachers may have a similar attitude, lengthening a futile conversation they know will not end with the other person considering veganism seriously. When I faced these types of exchanges, if the other person does not accept the “it will not happen overnight” answer, I tend to wrap the conversation up because it’s unlikely it will get anywhere.

However, many times after this, I felt unsatisfied. Not because I stopped the conversation, but because I felt that the “it will not happen overnight” answer is not that good. What if, because of some sort of magical encounter, we were offered the possibility of everyone becoming vegan tomorrow? Would we just reject it because we want to stick to our not-overnight argument? If the world became vegan tomorrow, would it cause a huge deal of animal suffering because it happened overnight? How can gradual veganism — reducetarian style — be better than overnight veganism? Is it better to have fewer vegans? If it is, why should someone become vegan today if someone else already did, and it is better to do it slowly, perhaps one person every day, rather than one thousand, or a million? See the contradiction?

I always thought that a better answer would be: “If everyone would become vegan tomorrow, the current global crises would be solved, and no animals would suffer a day more than if we never had exploited them in the first place. But, without further explanation, this may sound like a crazy answer from a naïve TreeHugger who doesn’t know anything about the real world. The vegan-deniers — and perhaps many vegans too — would look at me as if I was in denial of the inevitable rise in animals suffering and the unstoppable collapse of the world’s economy if everyone became vegan overnight.   

But what if I had the chance to give a further explanation?  What would I say to dispel the idea that I lost my mind? This article is the answer to this question.

The Magical Vegan Day

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Louise Wallis, an animal rights activist and investigator, was one of the witnesses who gave evidence at the famous ‘McLibel’ trial, in which the meat chain McDonald’s lost a legal case when they claimed the statement “if one eats enough McDonald’s food, one’s diet may well become high in fat etc., with the very real risk of heart disease” was false. Since then, it is safe to say that the high-fat-high-salt-low-fibre-ultra-processed food McDonald’s normally serves is not good for you —we already knew that it was not good for the animals and the environment. As a result of the court case, the Anti-McDonald’s campaign mushroomed, and it continues today — as the chain is a symbol of carnism and is still one of the companies that cause more animal suffering.

However, Louise is better known for something else. She created the World’s Vegan Day when she was the Chair of the Vegan Society. It’s 1st November, and it has been since Louise proposed it in 1994.  She did it to commemorate the 50th anniversary of the founding of the society and the coining of the term “vegan”. The day was chosen because, although it is not clear which exact day was it, the society started when a group of discontented vegans from the Vegetarian Society met in a London’s restaurant on one of the four Sundays of November 1944.  

But World Vegan Day is not the day I refer to when I say the “Magical Vegan Day”. That day has not arrived yet. That day may never arrive, actually. That is the day when, when everyone wakes up in the morning from east to west, everyone has become vegan. How? Magic, Alien’s meddling, something in the air, divine intervention, side effects of a new pandemic, it doesn’t matter — you choose whichever works better for you from a storytelling point of view. Somehow, all humans on planet Earth become vegan. This is a completely hypothetical scenario, and as such, from now on this article will be 100% speculation. It’s a philosophical exercise in the realm of ideas, not the real world. But, as you will see, it has practical — and moral — implications. Hear me out.

Let’s say that Magic Vegan Day is the 25th of June 2025. Close enough to today so everything is going to be pretty similar, but in a year when there is no trace of the current pandemic and things have gone back to “normal” — hopefully. That day people wake up, and when they look at the mirror — or any reflective surface — they say to themselves: “I am a vegan now.” And when they go to have some breakfast, they say to others: “you know what? I decided to become a vegan.” And everyone else replies: “me too!” 

What a day, eh? Now, according to most vegan-deniers and veganphobes, that would be the Doom Day, when civilisation, as we know it, would collapse, and death and suffering would become exponential. Well, I don’t’ think so. 

Being Vegan, Like Everyone Else

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When during the hypothetical Magical Vegan Day people say they are vegan now, what do they mean? They do not say that they will begin behaving as vegans do. They do not say they would begin reading the books vegans read. They do not mean they would be wearing the clothes vegans wear. They do not mean they will be eating the food vegans eat. They mean they will, to the best of their abilities, try to exclude all forms of animal exploitation of, and cruelty to, animals. Not one or two types of animals, like dogs and horses. Not one of two forms of exploitation, like factory farming or greyhound racing. All types of exploitation of all animals. 

When they say they are vegan now they mean they will change their lifestyle, as far as possible and practicable, to fit a new philosophy they have acquired called “veganism”. In doing so, for the rest of their lives, they will hold three fundamental beliefs (all animals are sentient beings that can suffer, all animal exploitation causes suffering to animals, and we should not discriminate individual animals for the species, sub-species, race or population they are classified into) and one overarching principle (ahimsa: do no harm to anyone or anything that can be harmed).

Before they dress up or use any product, everyone already subscribes to the philosophy of veganism when they wake up on the Magic Vegan Day. They are already convinced that the three “beliefs” mentioned above are true (because they now accept as facts all the evidence other vegans have been providing to them), and they are determined to avoid doing any harm to any sentient being, and therefore to guide their life from now on under the principle of ahimsa (whether or not they use this ancient Sanskrit term is irrelevant). 

If you think about it, that’s not that different than the day you became vegan — if you are vegan, that is.  At one point you made the decision, so you became a vegan right there and then even if you were still wearing leather shoes or there was still milk in your fridge. We don’t’ count our first day as vegans as the day we no longer have any animal products in the building we live in, or the day we got rid of all connections with animal exploitation. We don’t count our first day as vegans the day we stopped attending any party where non-vegan food is served, or shopping in any supermarket that sells raw meat.  We don’t count our first day as vegans the day we started turning the TV off when it showed someone riding a horse, or stopped using banks because they invest in companies who hire carnists. No, our first day as vegans was the day we decided to follow the philosophy of veganism, even if it may have taken us some time to get rid of all animal products we possessed and to be able to reject any new ones when we learnt about their connections with animal exploitation. 

So, during the 24 hours on 25th June 2025, everyone became vegan after waking up — not before, because you must be awake when you decide that. It is a voluntary resolution coming from thought and reflection. It is the recognition of a philosophy as something that makes sense to you, and a rational decision made on your own that would lead to a determination to change your behaviour. It is not a rushed decision. It is not a forced choice under duress. It’s a calm resolution that changes your identity. So much, that you are now happy to use the word “vegan” to describe which type of person you are. 

In our scenario, on the 26th of June, after everyone has accepted their new identity — unless they were already vegan and therefore that day is like any other day for them — every human in the world has become vegan. Not plant-based, not ostrovegan, not beegan, not veggan, not reducetarian, not flexitarian, no strict vegetarian, but vegan. Subscribing fully to the philosophy of veganism as defined by the Vegan Society — what these days is often referred to as an ethical vegan, to differentiate them from everyone who may call themselves vegan but they are only half (a dietary vegan, for instance), a quarter (a Lacto-vegetarian, perhaps?), or 10% vegan (such as a flexitarian) — to put an arbitrary percentage.

The First Day of the Vegan World   

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Most likely, by the end of the first day of the vegan world, oat milk would have run out of supermarkets and shops. Queues would have formed in most vegan stores, and rubbish bins and trash containers would be full of animal products. But there would not be panic. In fact, quite the opposite. That would be the day you would say good morning to the neighbour you always try to avoid. That would be the day you would finally call your parents after disowning you when you left the Christmas table in disgust. That would be the day you would smile at the pigeon on the lamppost. That would be the day you would hug all your co-workers. With a mix of excitement for the unknown and peace of mind for the finally known, that day you would feel part of humanity as never before. Even more, part of the Earth. That day you would not be alone. You and everyone else would share the same idea of peace. The same wish to be kind. The same resolution to turn things around. 

Does this sound too cheesy? Well, if you are vegan, remember that first day for you. How would you have felt if, when you told your parents, partner, or colleagues, they would have said “me too!” Emotional, right? As if your heart would have expanded. As if finally, everything fell into place. If on that day you actually felt some apprehension, that was because you were not sure how others would react. But if everyone had congratulated you and told you they would help you, you would have felt great. You would have felt you would not be alone anymore.

That first day in our story, those vegans waiting outside the slaughterhouse to perform their routine vigils realise no trucks are coming in with animals. Then they see how the slaughterhouse workers leave in mass and go to meet the protestors to shake their hands. They tell them how the farmers have stopped all the trucks with the animals and asked the drivers to bring them back to the farms — which they did gladly as they did not want to do that job anymore. They tell them that all the workers were going to quit because they had become vegan, but when they thought their boss was going to fire them, he came downstairs and said: “go home; we are closing down as a slaughterhouse, but we will continue paying you until we find something else to employ you for.”

That day, the animal farmers do two things: call the drivers to return all the animals that were going to the slaughterhouses, and stop any of their artificial insemination and breeding operations. The rest of the day’s routine would be as before. Still feeding the animals. Still cleaning the enclosures. But they are all vegan now, so they have one thing in mind. How to look after the animals for life and how to find another way of living. Some decide they will become an animal sanctuary. Others will use their land to plant crops. Others will go into forestry and rewilding. They all will stop any breeding and will start to reduce the feeding so as not to get their animals overweight (as they used to). They do not need to fatten them anymore. They can give them the right amount of food, so the reserves they have will last longer. But they know they need to organise themselves now because their priority is not to harm their animals. They feel guilty for the years they have done so, and because of that, they are very determined to transition to another livelihood without having to sacrifice any of the lives of the animals they brought into existence.    

That day, everyone is considering their options. Where to buy food. How to dispose of their woolly clothes. What to do with the leather sofa? And, above all, that is the day they all tried to figure out how everyone turned vegan at the same time. They chat with their friends and family. They talk to their colleagues and bosses. They plan, and they speculate. And everyone comes up with a project and an explanation that fits their beliefs and circumstances. 

The First Months of the Vegan World   

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It has dominated the news since the big awakening. Parliaments and Congresses in all countries are constantly meeting, passing new laws with very little opposition — as they are all on the same page now. International treaties — like the Plant Based Treaty — have been signed to ensure each country helps each other during these challenging times. All politicians know their job is to make the transition smoother. They are all intersectional eco-vegans now, so they will put party politics aside and think of the animals and marginalised human communities first. They are all excited because of the progress they are making. They remember how slow the system was to get laws passed to reduce fossil fuel emissions. They remember the frustration of seeing the climate crisis measures been resisted and watered down. They remember how hard they had to work to get real equality and equity for those underprivileged. They remember how sometimes they had to vote against their conscience because of the heavy lobby they endured from the animal exploitation and fossil fuel industries. 

But all that is over now. The same lobbyists are contacting them saying that their clients have become vegan, so they stopped all animal breeding or oil extraction and planned to plant forests in the land they own. Now that all their constituents are vegan, each politician tries to outdo each other in how fast they can propose new laws and how strong their new policies would be for a fair and speeding transition of the economy.

There is now new legislation to subsidise animal farms to keep their animals alive and well for the time being. State animal sanctuaries are created, and farmers start to take some of their animals there so they can give more space for the animals they will look after for the duration of their natural life. Farmers will be paid to do that, and with time, when they have increased space as there is no longer breeding, they will start using their land for profit. To grow vegetables that are now in great demand. To plant trees as the government would pay them for that too. From all the options animal farmers have now, ‘Rewilding’ and ‘Regenerative Veganic Farming’ are the two most popular. They all look far more profitable than their old animal farming, as the demand for plant-based products is soaring. Farmers have land, and in the vegan world, having land means lots of potential for profit.

The other laws that have been passed are the subsidies for new food technologies such as fermentation using bacteria and fungi cultivation. The technology already existed, but now many funds that used to go to animal agriculture have been diverted to these types of food production. Many brewers have now switched from producing alcohol to producing food via fermentation. And they can do it on a great scale, and incredibly fast. 

The first few weeks the number of plants available to eat went down so quickly, that for a moment it may look as if mass starvation was going to be inevitable. But two things came to the rescue: the speed with which fungi and fermentation companies managed to scale up their production, and the rechannelling of a good proportion of the food destined to animal feed— now that no new farm animals are born anymore and those alive do not need to be overfed any longer.

New business opportunities have germinated everywhere. Replacing leather seats in cars has made some quick-thinking businesspersons very rich. The shares of already established vegan companies have gone to the roof. And, of course, the billionaires. They all have become vegan too, but they are still competing with each other. But now, they no longer will compete for who builds the biggest rocket, but who can produce more plant-based or fermented food quicker, create bigger animal sanctuaries, or develop new technologies that help the transition. And the governments let them, of course. 

All vivisection and intrusive animal research have ended, but this does not mean that lab scientists (all vegan now) are unemployed. They have their work cut out. All the already existing alternative testing methods need to be scaled up now, and those which were in their initial stages of development need to be speeded up. A whole new scientific discipline arises: non-intrusive animal sterilisation. They must find ways to guarantee that no more farm animals will be born until the numbers are sufficiently down so stable populations can be kept in selected sanctuaries. It may take many years to get there, but in the meantime, they must find technologies that give the current animals the best possible existence, considering that many are already so genetically modified that getting to older ages could make them suffer too much. Therefore, euthanasia may need to be used for some, which will be administered as it is done today with dogs or cats — not abattoir style. Animal Welfare sciences will become the new prioritised scientific discipline, so all ex-vivisectors have a new subject to channel their expertise.      

The First Years of the Vegan World   

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It’s looking good. The first “new-era crops” have now been harvested, and the transition of plant-based agriculture is going well. It only takes one year to plant annual crops, so fields that were wasted for pasture and animal feed are now producing high yields of food for humans. The non-veganic organic crops are still using manure from the animal sanctuaries (where are never short of staff as many people want to volunteer in them). They are allowed to get them till 2045, but after that not anymore — they will not be needed as the regenerative humus-building systems that are being developed would be fully productive by then. 

Vegan cuisine has become high art, and top chefs are the celebrities of the day. Words like “meat”, “burger” or “cheese” are not used anymore. Manufacturers of fermented foods have moved away from the carnists shapes, tastes and colours of animal exploitation. There are no longer fake meats, but fake fruit, fake vegetables, fake pulses. Plants as food in their most natural way have become the thing to imitate, as for a while some vegetables became luxury items. Not anymore. There is space to grow them now, but as transport to long distances is no longer the norm, growing them in greenhouses, vertical farms, or synthesising their nutrients via fermentation is what people are trying. Everyone grows food in their gardens and balconies. It has become one of the most popular hobbies. And since the human population is no longer growing due to a massive increase of voluntary abstention of procreation, and people feeding habits have become healthier — which means smaller portions — there is less demand for human food.  

The new economy has already stabilised. There is less need for government intervention and many farmers and business people have successfully transitioned into it.  All restaurants are still in business, but now they just serve vegan food. All fashion brands are still in business but now they don t use wool or leather. All the supermarkets are still open but they no longer sell meat, eggs, honey or dairy products. All fruit producers still sell fruit, but they don’t’ use shellac to make it shinier. All pharmaceutical companies are still in business but now they don’t use animal products or test on animals — the advances in botanical pharmacology and AI chemical testing, boosted by entrepreneurs’ investments, have been staggering.   

The projects to colonise the moon and Mars have been scrapped for now, and all their technology and funding has been diverted to produce food on Earth. The big rocket boosters are now used in enormous fermentation plants, and the air protein technology that was initially developed by NASA to produce food from the CO2 in the air using some special bacteria (this is true, they did it in the 1960s) has been scaled up. Each city has its big fermentation plant, or they are building them. With the increase in the use of renewable energy sources, cities are competing with each other to see which one would be the first carbon-negative self-sustained city in each continent. 

Zoos are still operating, but no longer open to the public. They have been taken over by universities and museums — as these are only allowed to collect “specimens” from zoo animals when they die, no longer from wild animals in the wild.  Zoos don’t’ breed animals anymore, of course, but now it’s all about giving them the best remaining days of their lives in peace. When possible, inner-city zoos moved their animals to bigger ones outside cities or to specialised animal sanctuaries in the right environments. There is no hunting or wildlife trade anymore, which, together with rewilding and the halt of human expansion, save many species that were on the brink of extinction. 

The First Decades of the Vegan World   

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By 2045, most of the farm animals that were alive on the Magic Vegan Day will have died of old age or be humanely euthanised. A select few had been allowed to breed in experimental sanctuaries where they try to correct all the genetic aberrations caused by centuries of artificial selection, hoping that the biological phenomenon called atavism will kick in, and the animals will revert to the original forms before they were domesticated. A whole new scientific discipline, Atavismology, has been dedicated to that. When all the standard sanctuaries are no longer needed and their land can be used for rewilding and veganic farming, some will actually become natural reserves where the original-looking cows, bulls, goats, horses and sheep can live a natural life creating stable populations without the need of any human intervention. Regarding the chickens, pigs or llamas, this will not be needed as the wild counterparts from which domestic versions were created still exist — and all wild animals and their homes are protected now. 

If everything works out, no species of domesticated animals will become extinct because of the transition to the vegan world. For farm and lab animals, their genetic and behavioural domestication will be removed from them, and they will return to Nature — which, via natural selection, can decide if they stay, evolve or disappear, as any other species. For dogs and cats, they will continue to be companions of humans, but all selective breeding to maintain pedigree “breeds” will stop so they will end up looking more like wolves and wild cats.

Once there are no longer first-generation farm animal sanctuaries anymore, people can still watch horses, cows and chickens in “photographic safaris”, but the animals are wild for all intent and purposes. There are no zoos with alive animals anymore, but some have become museums. The 25th of June has become the “Animals Remembrance Day”. It’s a Holliday where people remember the trillions of animals that used to be killed and tortured every year. The day starts with everyone asking for forgiveness and ends up celebrating the coming of the new vegan world.  

The data is confirming it. The temperature of the planet is going down. The CO2 and methane emissions have been reduced massively now that most farm animal sanctuaries have become forests or veganic farms. The rewilding projects are going well. Natural areas have now been connected with each other and they are big enough to not require human management anymore. Many previously damaged ecosystems are becoming stable. But one of the most dramatic effects is happening in the oceans. As nobody has fished any aquatic animal since the 25th of June 2025, the whole marine ecology has rebooted itself. Some of the boats that used to go out to capture animals are used in the thriving industry of cetacean watching, now that the populations of whales and dolphins have increased so much. Some of the former fishers transitioned into the transport industry, as the transport by air has declined considerably and sea and river transport has increased. No fossil fuel is used anymore, and sailing has been revitalised. And many pilots still fly, but now in big solar-powered planes or enormous zeppelin-style aircraft.  

The tourism industry has survived remarkably well, as people who stopped travelling far now visit closer destinations — which, together with the cessation of wildlife trade and animal farming, has reduced considerably the risk of zoonotic pandemics.  No more donkeys or elephant rides anymore, but a trip to the local animal reserve will allow you to still see these animals, behaving as nature intended. 

The political system has changed radically. They call it ahimsa politics now. The first scrutiny any new policy or law has to go through is the ahimsa test. Does it harm anyone? Does it harm any human, animal, sentient being, or the environment? And only politicians who lead by example are voted now. The ones with the smallest carbon and blood footprint. The ones who have done more to spread the philosophy of veganism, which is now taught in all schools as the ethical baseline. This means that people now trust the new inclusive transparent accountable democratic governments and the narratives of conspiracy theorists no longer have traction. 

Everyone now is an intersectional abstinent ethical eco-vegan, but they do not use these labels anymore — not even the word vegan. However, the Ethical Fruitarian movement which tries to avoid harming plants as well as animals has grown, so there is still room for envelope-moving radicals living at the fringes of mainstream society. And thanks to the new complete food supplements, the intersection between neo-meditators and ethical fruitarians creates an interesting group of neo-ascetic vegans (who fast a lot and consume almost nothing), some of which are still linked to secular Buddhism. 

Religions still exist, though. They are adapting as they had no choice. For many, it was easy, as they already had ahimsa as part of their tenets. For others, an official reinterpretation of the scriptures was necessary, but they all found a way — because all religious leaders were vegan too. The golden rule of religions has been replaced by the platinum rule: do no harm to whoever or whatever can be harmed. But the world is more secular, anyway. 

Back to the Real World

A Vegan Word. Diagram created by Keenan from Jordi Casamitjana’s book Ethical Vegan

This article was not intended to sound like a “prophecy”. I know that the Magic Vegan Day will never become a reality. But I hope the vegan world will. Not because of magic, but because of perseverance. If we are lucky, we may get to the same scenarios I described in the last two sections, but they may take much longer than years and decades — more like centuries and generations, as I explain in the last chapter of my book Ethical Vegan.  And because it will take so long, many will suffer the consequences.

Those who survive the impending disasters of climate change will persevere with more resolve toward making the world vegan. Nobody will listen to the climate sceptics and conspiracy theorists anymore — well, nobody that matters, anyway. People would have seen it with their own eyes. But because it will be all gradual, because it will take a long time, there would be many unnecessary deaths and destruction. Many species (with all the individual animals they are composed of) will become extinct because of how slow our progress to the vegan world is, and inequality will remain for much longer as those privileged who are not vegan will keep trying to take advantage of everyone else. Unfortunately, in a world where not everyone is vegan, the ruthlessness of the oppressors and exploiters may give them a temporary advantage. But if we persevere, not even them will be able to avoid succumbing to the will of the decent people. When we reach a critical mass, we will accelerate the journey towards the vegan world, but until we get there, we will have to accept the slow progress that ideological pragmatism and commercial reductionism are bringing to us.

Being vegan is not behaving in a particular way. Is thinking in a particular way. Is having the philosophy of veganism as your main ethical drive. And it’s the thinking that makes the difference, not the behaviour. It is the attitude, not the consumer habits. It is the conviction of doing what is right, not the following of particular rules because everyone else’s does. Because of that, if the world became vegan overnight, it would be saved. The animals would be saved. The people would be saved. The planet would be saved. Because what would have changed is the beliefs and attitudes of people, putting them all on the same page, making them feel the same urgency, uniting them to address all the global crises in a meaningful and effective way. Everyone singing the same song of peace and kindness in perfect harmony.  

So, from now on, the next time a vegan-denier asks you ‘what would happen if everyone became vegan overnight?’, you could answer differently. 

You could say: “something wonderful!”  

“Originally from Catalonia, but resident in the UK for several decades, Jordi is a vegan zoologist and author, who has been involved in different aspects of animal protection for many years. In addition to scientific research, he has worked mostly as an undercover investigator, animal welfare consultant, and animal protection campaigner. He has been an ethical vegan since 2002, and in 2020 he secured the legal protection of all ethical vegans in Great Britain from discrimination in a landmark employment tribunal case that was discussed all over the world. He is also the author of the book, ‘Ethical Vegan: a personal and political journey to change the world’.