Going Vegan - What Does The Science Actually Say?

Quick, Frank, do something sciencey for the photographer!

The Only Way is Ethics
    When I was a wee young lad the debate over meat-eating was about the morality of whether it's OK to kill other animals for food.  It’s an important issue and naturally leads to numerous follow-on discussions e.g. animal testing, distinctions between humans and other animals, what constitutes consciousness etc. etc.  These are some spicy questions (#foodpun) so naturally it becomes anarchy when people discuss it on the internet.
    In recent years, the discussion has shifted into the realm of science, incorporating the dietary effects of meat-eating and the impact of widespread livestock farming on an already strained environment.  Moving from philosophy to science lands it squarely on my doorstep, so I’ve decided to tuck in (#foodpun) and try to pull some facts out of the quagmire.    
    Currently, 8% of the world is vegetarian and a smaller minority - around 0.5% - identifies as vegan.  There’s a bit of disagreement over whether vegan simply means “plants-only diet” or if it means a lifestyle which excludes any form of animal exploitation.  For this blog, I’m going to use the former definition because I’m focusing on biochemistry and environmental science rather than applied ethics.  Sorry if that's not how you use the term.
    I should also warn my readers that wherever you sit on this extremely important debate, there will be one or two things in the blog which will probably make you uncomfortable.  My aim, as always, is not to espouse a particular belief but to present the facts as best I can.  If you read things you don’t like then don’t worry, so did I.  Hopefully I'll be able to present it objectively and you won't even be able to tell what my personal feelings are.

It might look vegan, but that bread contains a bit of Shrek's corpse

A Matter of Taste (#foodpun)
    In my previous blog, I talked about the controversial art of IQ testing and the difficulty you run into when trying to make up your mind about it.  The problem is that there’s so much evidence both for and against - not to mention a bunch of misinformation, pseudoscience and confusing Netflix documentaries - that it's hard to extract a clear answer.  Unfortunately, the same is true of veganism.  But first, let’s address some crucial misconceptions about food.   
    You probably got taught in school that there are five or six “food groups”, usually depicted in a colourful pyramid or a non-threatening pie chart.  The idea of food groups was devised in 1972 by Sweden’s National Board of Health and Welfare to combat dietary shortages across the country.  To avoid widespread malnutrition, the Swedish government wanted to make a simple guide advising people on what to eat.  It’s a noble idea but it suffers from two big problems 1) you can’t simplify dietary science because it’s freaking complicated and 2) they don’t seem to have based their suggestions on any in-depth clinical trials whatsoever.
    To make things worse, there’s a fair amount of evidence that in America the USDA’s version was heavily influenced by lobbying groups representing companies within the food industry to make certain foods more of a priority than others.  So although the idea of food groups is a good one, I’d take it with a pinch of salt.  #foodpun
    When the standard food groups are listed, they usually lump each type of meal into one category, rather than reflecting the complex reality that most foods contain a mixture of nutrients.  Meat, for instance, is usually listed as a protein despite containing lots of vitamins, while vegetables are usually put in the vitamin category despite containing lots of protein.  Then there's fiddly stuff like the fact that some nutrients can be classified in more than one category and even be converted into each other.
    As if that weren't complicated enough, there are 7.5 billion human metabolisms out there and we don't know a great deal about how they work (like the fact that gum disease links to Alzheimer's…what’s that about???) Human biology, especially the study of food, is so complicated that it’s difficult to make any absolute claims, which means there is no such thing as an indisputable food “fact” other than the obvious one...we need it to not die.
    All of the conclusions we have drawn about human diet are statistical likelihoods which differ from person to person, meaning you have to be very discerning with what you accept.  What works for one body might not work for another. 

Responses to the new Swedish flag design have been mixed

Myth: Vegans don’t get protein.  
    This is completely wrong, but it's hardly surprising that people have this misconception based on the food-group model.  Actually, plants contain a ton of protein and a vegan diet gives you everything you need to build muscle mass.  Just ask nature’s most dedicated vegans - gorillas.    
    To say your body needs meat is not really accurate.  But it’s also not accurate to say your body needs fruit and veg either (sorry moms of the world).  What you really need are the chemicals the foods contain and as long as you’re getting them from somewhere, your body doesn’t seem to be all that picky.    
    That being said of course, living on a diet which is too narrow does have knock-on effects.  For instance, a lot of communities in the Arctic circle live in a region where growing crops isn’t possible so their diet is exclusively carnivorous - consisting of caribou, fish, seal, rabbit, birds and eggs.  Or consider the Maasai tribesmen of Africa who subsist on a diet of meat, milk and blood (with a bit of maize thrown in).
    These peoples are clearly not extinct and have been living on a meat-only diet for generations.  But, as you might expect, this isn’t the healthiest way to human.  You’ll find a bunch of literature on anti-vegan websites citing studies by anthropologists like V. Stefansson and G. Mann claiming the Inuit and Maasai are in perfect health (Mann even claimed the Maasai had immunity to certain diseases).  However, this research was invariably drawn from small sample-groups, anecdote rather than evidence and included a lot of vague and untestable statements.  
    Later and more rigorous studies carried out by Nestel (1986) Bjerregaard (2003) and actually Mann himself, found that an exclusively carnivorous diet leads to a higher chance of heart disease, bone disease and...wait for it...symptoms of malnutrition.  Shocker.  So while it is true that a meat-heavy diet technically has all the nutrients you need to stay alive, it doesn’t do you any favours.

A lesser known food group...

But Isn't Our Body “Built” to Eat Meat?
    The answer to this question is a pretty clear ‘yes’ and there's a bunch of evidence to back it up.  For instance, carnivorous mammals have small fat cells in their adipose tissue (for metabolic reasons I won’t go into) while herbivores have much larger fat cells.  This means you can get a pretty good reading on how a species' diet evolved by looking at their fat tissue, and ours is much closer to that of omnivorous mammals than herbivorous ones.
    Then take stomach acidity.  Carnivores need to have way more acidic stomachs in order to digest the bacteria found in meat.  Human stomach acid is significantly more concentrated than that of herbivores (by a factor of around ten) lining up neatly with omnivores.
    Then probably the strongest bit of evidence: our body is not capable of synthesising certain nutrients like vitamin B12, despite needing them to live.  Today, vegans have to take supplements or eat fortified foods to stay healthy - a practice not available to early hominids so their source of B12 would have necessarily been meat.
    So yes, humans did evolve eating meat. But (and this is important) that doesn’t mean we are biologically compelled to live the same way.  I mean, if you want to play the “evolution built us like this...” game, I’d point out that we aren’t really built to walk upright and doing so is pretty disastrous for our backs.  Yet we insist on doing so. 
    Evolution may have set us up a certain way but that doesn’t mean there’s a magical law of Darwinism which says we have to keep repeating it.  Evolution doesn’t make creatures “better” or “optimal”, it just works with what it’s got and we can absolutely improve on its designs.  I mean...we invented cosmetic surgery for precisely that reason.
    However, to flip that point around we can just as easily make it an anti-vegan argument by saying evolution made us walk a certain way and when we deviated from that arrangement, it started causing problems from our backs - couldn’t meat-eating be the same?  I mean, if evolution made us one way, deviating from that (even if it's an inconvenient design) could be bad news. 
    Switching to a vegan diet does lead to weight-loss and an increase in emotional well-being in the short term (that's widely reported and verified) but what happens in the long term is less clear.  The question of what we are “built to do” is therefore a tad misleading.  The question should really be: what happens to your body if you stop eating meat?  And I’m afraid the answer is not a simple one.
 
Ah Shucks, This is Gonna Get Ugly Isn’t It…
Yes, I’m afraid so.

They're either arguing or they both really want to eat that explosion

The Subtle and Downright Inconvenient Truth
    People talk about health as if it’s a progress-bar in a videogame which goes up and down until it drops to zero and you die.  In reality there are so many different aspects to health that sometimes (because evolution isn’t your friend) they contradict.  For example, I knew someone as a young adult who had cancer.  She was given a course of chemotherapy drugs which killed the cancer entirely.  But at the same time, they shredded her immune system and she died from a viral infection.  Were those drugs "good" for her health or "bad" for it?  Without them she would have died of cancer but because of them she died of an infection.
    Or imagine someone who smokes a couple of cigarettes a day but never eats fast-food or snacks and exercises regularly...compared to a non-smoker who sits on the couch all day and lives on a diet of chocolate and chips.  Which of them is in better “health” the smoker or the non-smoker? 
    Health is not one thing and biology rarely works on absolute cause/effect.  In physics you push a ball and it rolls with a certain momentum every time, but in biology the same chemical in the same person on two different days can have two different outcomes.  
    It isn’t difficult to find testimonials from people who got sick when they switched to a vegan diet, and vice versa: you can find plenty of convincing stories from people who went vegan and reported immediately feeling better.  The problem is that both groups are telling the absolute truth, so the only way of getting hold of anything useful is to consider one of the most important devices in the science arsenal: a meta-analysis.  
    A meta-analysis is a study of studies in which a general consensus is arrived at by examining what all the research says and averaging it.  They can take years to assemble because scientists writing them gather all the research they can from all over the world and evaluate the methodology of each study before drawing a conclusion.
    When it comes to meat-eating, the biggest and most thorough meta-analysis I’m aware of is quite a recent one, published on 19th November 2019 by Bradley C Johnston and 20 other researchers (The Annals of Internal Medicine, Volume 171, Issue 10) in which they analysed studies of red meat and processed meat compared to cancer-mortality rates.  Johnston’s meta-analysis covered 6.1 million test subjects, ranging in age from 3 to 77 going all the way back to 1904.
    Furthermore, and quite critically, their study received absolutely no funding which means they didn’t have a financial incentive to uncover a specific outcome and did everything off their own back.  What did they find?  
    Well, the only absolute conclusion they could sift from this staggering dataset was that limiting red meat intake by three meals per week would lead to seven less cancer deaths in every one thousand people, while limiting processed meat intake by the same amount would lead to eight less deaths for every thousand.  Now, let me say that statistic in two different ways, just to show how easy it is to spin the data…

Pro-Meat Eating Spin:
Eating red or processed meat won’t even increase your chance of dying from cancer by 1%
 
Pro-Vegan Spin:
Red and processed meat cause 70-80 million deaths a year
 
In the first instance I’ve taken the cancer deaths as a raw percentage which gives us 0.7% - the risk of meat sounds insignificant.
 
In the second instance I’ve taken the number of meat-cancer deaths and expressed them as a percentage of the global population.  Suddenly meat sounds like a mass murderer.

    But that’s just cancer.  What about all the other diseases which have been linked to meat consumption?  Well, again the picture is murky but one of the most thorough studies I know of is the one reported in the British Medical Journal 4th September 2009 by Tammy Tong, who examined a variety of health effects in over 40,000 people and found vegans were at lower risk of heart disease than omnivores, which seems to make sense.  After all, Maasai tribesmen and Inuit communities have a higher chance of heart disease from eating loads of meat.
    BUT (kick-in-the-head-time) vegans turn out to be at a higher risk of suffering a stroke, which means reducing your meat intake will improve your heart health but cutting it completely might put you at risk of a brain aneurysm.  Subsequently, going vegan could be simultaneously safer and more dangerous, depending on what other factors there are in your body.  If heart disease runs in your family you’re possibly better off limiting the red and processed meat, but if strokes run in your family going vegan could be putting you in harm's way. 
    Nature has seemingly presented us with a demonic trolley-problem in which we have to chose between our own health and the lives of other living things.  What do we do when it's us or them?  Do we decide that the allegedly smarter animal (us) deserves to live more than the allegedly dumber animal (livestock)?  Where do we draw that line?  How smart does an animal have to be before we decide not to kill it for our survival?   
    And that's just two diseases.  There's a whole galaxy of studies out there which point in both directions on the meat-eating issue.  Eating meat and going vegan both have benefits and risks, so I'm afraid Science is of no help there.  My advice as far as biology goes would be to consult a qualified doctor, rather than going by what you’ve seen in a documentary or read in a YouTube comments section.  The ethics is up to you.  Sigh.  

Pretty sure I'm gonna get McSued for this

Hotter By The Minute  
    While the dietary science of veganism is nuanced, the climate science is a lot clearer.  Farming livestock on the scale we currently do isn’t logical.  For one thing, it’s not a very efficient use of land e.g. 7 kilograms of grass is needed to produce 1 kilogram of beef, so cattle-farms take up way more room than crop-farms feeding the same number of people would.
    Another big problem is that to keep those animals healthy farmers have to use a lot of antibiotics.  Like, a lot a lot.  In fact, this is largely what’s behind the bacterial apocalypse we’re heading toward- 90% of antibiotics used in the world are actually given to livestock and it’s that which is leading to widespread bacterial immunity.  So...that’s not great.
    Then there’s the effect of livestock on climate change.  The number varies depending on the study you read but somewhere between 15% and 30% of all greenhouse gas emissions come from farming animals.  Half of that problem comes from the simple fact that animals tend to fart and burp indiscriminately.  Yeah.  That’s right.  You heard me.  Farting and burping is legitimately part of climate Science.
    If you read the literature on this topic you’ll come across the polished phrase “enteric fermentation” but that’s ridiculous fancy talk.  Animals fart and burp with abandon, kicking out huge quantities of methane all the live-long day from both ends and this is a major problem for absorbing heat in the atmosphere.
    There’s some interesting research into changing livestock diets (notably by giving them more seaweed) which cuts most of the offending gases, but there’s still the fact that animals produce manure.  A ton of it.  There’s a joke I desperately wanted to put here about “a ton” of manure but it would have involved a curse word and I have to keep the blog PG.  Darn it.
    Besides all this bullcrap, there’s other issues like fertilisers needed for the grass, processing of the meat, transporting it etc. etc. and the science is pretty cut and dried…livestock farming is a major problem for climate change.  Unless the cows learn to drive Teslas, of course, in which case problem solved.

Dude, I don't care if it's bad for the environment...wind the window down if you're gonna do that!

So...what do we do?
    Nobody has ever run this experiment (obviously) so all the information we have on global veganism comes from simulations, which can be difficult to get right because there are so many variables.  For instance, if you buy a kilogram of chicken from a farm down the road that has less of an environmental impact than buying avocados shipped from South America.  Local produce is always better, but some countries don’t have the climate to make crops, so importing is their only option.
    There’s also the problem of topsoil which has to be rolled and tilled regularly for planting, which releases CO2 into the air.  If we switched to crops humans can eat instead of feed for animals, we’d have to be rolling and tilling the soil more regularly (just by the nature of what plants we can digest) which has its own greenhouse gas cost, offsetting some of the savings we’d make.
    However, all the models I’ve seen come to the same conclusion even with these compounding factors: if we switched to vegan diets we would cut a significant chunk of our greenhouse gas emissions.  Would it solve the climate problem?  No.  But would it buy us a few more decades?  Yes.  And frankly, when it comes to the end of the world, I figure we should consider taking every chance we can get.
    Going vegan is also a lot easier to do than cutting energy or transportation needs.  Our homes need heating and our kids need to be driven to school so that's not easy to get rid of...but changing our diet is quite simple.  Just buy less meat.

Buy less what now???

What if the World Went Vegan Overnight?
    Now, before we all go rushing out to buy Linda McCartney sausages and whatever the hell kale is, there’s a few things to consider.  All the simulations we have, work by comparing the current world to one in which everybody is already vegan.  There are very few studies looking at the transition period and if we don’t handle that carefully it could be catastrophic.
    Suppose we switched to vegan diets in a single month.  What would we do with all the animals?  There are two options.  Either we turn them loose and 99.9% quickly die of starvation, so we suddenly have billions of animal carcasses rotting everywhere leading to a bloom of fungus which is like detonating a carbon dioxide bomb in the atmosphere...something we sort of want to avoid in environmental terms.  Not to mention, forcing these animals to starve in agony might arguably be worse than the bolt-gun of a slaughterhouse.
    The alternative would be to keep all those animals where they are and turn the farms into preserves.  The problem with that is that we’d be using the same amount of land for animals and their feed plus crops to feed ourselves, so we’d actually end up with less land available for a while.  
    If we had done it two hundred years ago things would have been fine, but our ecosystem would be in trouble if we switched too quickly now.  The answer is therefore to do it slowly.  A few more people every year buying less meat will send messages to the food industry that there’s less of a demand, which will make them shift their practices.  They’ll stop artificially inseminating the animals they have and their animals will die in stages.  The answer isn’t to get everyone vegan in a flash, it’s to do it over a few decades.

18th Century milkmaids selfishly not understanding climate science

Are There Environmental Problems With Dropping to Zero Meat?
    There are two potential complications we need to be aware of if we switch to veganism globally, one of which is blight.  It’s not a widely discussed statistic but around 40% of Earth's crops die every year due to it.  A particularly virulent strain can spread through a farm and cripple it within weeks but at the moment it doesn’t cause much of a problem because if crop yields are down, people can supplement their diet with meat.  But if crops are the only things we’re eating, a bad year of blight would give us the Irish potato famine on a planetary scale.
    Switching to zero meat globally is putting our food supply in a narrow basket and the risks of that need to be planned for.  I'm not saying abandon the plan and stick to livestock...just saying we need to factor in the risks.  I mean, that’s the whole premise of the movie Interstellar - a blight hits the world and we lose most of our crops, leading to dust-storms and the collapse of civilization.  That could really happen and things got so bad in the movie we had to resort to asking Matthew McConaughey for help.  This is Matthew McConaughey…

Saving the planet y'all

    The other problem with switching to zero meat globally is that it doesn’t work for economic reasons I don’t pretend to understand.  I've had a few people try to explain the gist of it to me and here’s what I *think* the central idea is: there are places on Earth where it’s not practical to farm crops, so keeping animals is sometimes a better solution because they are the best way of converting nutrients from the soil into a form humans can digest. 
    Take some of the mountainous regions of West Asia for instance, where you can’t grow grains in the poor-quality soil, but you can farm goats who survive on the tough grass which grows there.  In the West, most of the commercial meat comes from faceless and heartless corporations, but in Africa and central Asia a lot of the meat comes from small-scale farmers trying to make it through the winter with their family intact.  If everyone went vegan, those farmers, along with their children, have no economic security and starve.

I just wanted to order a Subway

A Flexitarian Future?
    The ethical debate around meat-eating isn't as simple as "cruelty to animals is wrong so we shouldn't eat meat".  That's not the part anyone disagrees with...at least I don't think it is?  Most meat-eaters I've conversed with on the topic don't like cruelty to animals one bit.  The real problem, the one that's much harder to solve, is that certain economic and biochemical principles seem to say that if people want to stay alive and healthy, they stand a better chance of doing so at the expense of other animals.   That's what the argument is really about. 
    Also, just to address the elephant in the checking account, a vegan diet is currently more expensive than a meat-eating diet and some people don’t have the money to afford the luxury.  Yes, the more people who switch to veganism the lower the price will be in future...but we aren’t there yet.  So if you’re privileged and wealthy enough to afford a vegan lifestyle that’s awesome and you’re helping do your bit for the world, but for some people buying cheap meat is the only way to keep their children healthy and I'm not sure you can really criticise them for that.
    We do need to cut livestock farming drastically, but I will concede that dropping to zero-meat comes with its own problems - environmental, economic and ethical.  The answer may not be a global “no meat” policy therefore but a more achievable and realistic “less meat” one.  It's not a perfect solution, but nature hasn't given us a perfectly solvable problem, so we gotta do the best we can.
    The safest thing to do, both for the environment and our health, might be to gradually and cautiously move toward a diet which has less meat in it, while recognising that not everybody can or should go fully vegan.  That's a difficult message for both sides to swallow (#...ummm...foodpun???  Yeah, I'm not in the mood anymore either).  For meat-eaters, it's time to recognise that the world needs vegans and lots of them.  For vegans, it's important to recognise that everyone going vegan probably isn't the best way to do things either.  Which leads to my final point.
 
Don’t Be Jerks To Each Other
    Meat-eaters: don't be jerks to vegans.  Don’t mock them for their views, don’t make the whole “but how can you live without bacon?” joke, don’t deliberately eat steak in front of them (like Fox news reporter Jesse Waters did live on air during an interview with a vegetarian writer) and certainly don’t spend hours justifying why you do eat meat - that just makes you seem insecure and defensive.  Frankly, the world needs all the vegans it can get, so if people have made the choice to eliminate meat from their diet you should probably be thanking them.
    Vegans: don't be jerks to meat-eaters.  I knew a vegan once who said meat eating was worse than the holocaust because, according to him, on sheer numbers it's a bigger extermination of living beings.  Some readers might agree with that statement but even if you do...what do you hope to gain by telling meat eaters they're worse than Nazis?  Do you really think that's going to help them change their minds?  Some people eat meat because it’s healthier for them and cheaper for their families and I’m not sure you have the right to tell them to compromise their health (or the health of their children) for your moral values, no matter how strongly you hold them.
    There aren’t any easy answers to some of these questions and often people come to a decision on meat-eating with trepidation and unease.  I know I did.  But if animal suffering is something we want to avoid (I think most people can agree on that, omnivores and vegans alike) let’s try to treat other human animals with compassion too.  It’s a start, right? 

Image Credits:
Scientist with vegetables: Freepik
Shrek-burger: ethical
Pie Chart: Forksoverknives
Food Group: Zazzle
Argument: thedailystar
McDonalds: change
Cowcar: Babajana
Blackboard: eightieskids
Milkmaids: pinterest
Matthew McConaughey: screenrant
Moral Problem: psmag