Is a vegetarian diet man's "intended" diet?

March 11, 2009 10:30 AM

Does the evidence indicate that man was intended to eat meat, or is a vegetarian/vegan diet the superior and intended one?

Is there evidence one way or the other that has surfaced in recent years? What would you say to people who strongly hold the opposing view?

posted by sorrenn to health & fitness (53 comments total)

From the Vegeterian Resource Group:

Evidence of Humans as Omnivores

Archeological Record
As far back as it can be traced, clearly the archeological record indicates an omnivorous diet for humans that included meat. Our ancestry is among the hunter/gatherers from the beginning. Once domestication of food sources began, it included both animals and plants.

...
Fermenting Vats
Nearly all plant eaters have fermenting vats (enlarged chambers where foods sits and microbes attack it). Ruminants like cattle and deer have forward sacs derived from remodeled esophagus and stomach. Horses, rhinos, and colobine monkeys have posterior, hindgut sacs. Humans have no such specializations.

Jaws
Although evidence on the structure and function of human hands and jaws, behavior, and evolutionary history also either support an omnivorous diet or fail to support strict vegetarianism, the best evidence comes from our teeth.

The short canines in humans are a functional consequence of the enlarged cranium and associated reduction of the size of the jaws. In primates, canines function as both defense weapons and visual threat devices. Interestingly, the primates with the largest canines (gorillas and gelada baboons) both have basically vegetarian diets. In archeological sites, broken human molars are most often confused with broken premolars and molars of pigs, a classic omnivore. On the other hand, some herbivores have well-developed incisors that are often mistaken for those of human teeth when found in archeological excavations.

Salivary Glands
These indicate we could be omnivores. Saliva and urine data vary, depending on diet, not taxonomic group.

Intestines
Intestinal absorption is a surface area, not linear problem. Dogs (which are carnivores) have intestinal specializations more characteristic of omnivores than carnivores such as cats. The relative number of crypts and cell types is a better indication of diet than simple length. We are intermediate between the two groups.

Conclusion
Humans are classic examples of omnivores in all relevant anatomical traits. There is no basis in anatomy or physiology for the assumption that humans are pre-adapted to the vegetarian diet. For that reason, the best arguments in support of a meat-free diet remain ecological, ethical, and health concerns.

posted by GuyZero at 10:35 AM on March 11 [13 favorites]

We evolved from omnivores -- our dentition proves that. (Canines = biting and tearing, etc). But having (arguably) achieved self-awareness we can choose to eat whetever we like as long as it sustains us. A well-planned vegetarian or vegan diet can do that. Superior? That's moot. "Intended"? By whom? I don't really care what anyone eats as long as they don't try to tell me what to eat.
posted by Guy_Inamonkeysuit at 10:35 AM on March 11 [2 favorites]

First of all, I would avoid using the word "intended" there. If you say man was intended to eat diet A, then it makes it sound like some kind of moral failing if he chooses diet B instead. (cf. your use of "superior and intended" implying that the two are equivalent.) If you say merely that man evolved to eat diet A (which I think is more accurate), it does not necessarily follow that diet B is inferior (even though some people will try to convince you of that all the same).
posted by DevilsAdvocate at 10:38 AM on March 11 [7 favorites]

Intent requires one who intends. There is no law written on the face of the universe one way or another on this issue.
posted by Ironmouth at 10:39 AM on March 11 [2 favorites]

A vegetarian diet doesn't provide all the essential amino acids unless you're very deliberate or take supplements. There's no question that our species evolved as an omnivorous one and a vegetarian diet ignoring that fact takes serious health risks. Whether the overwhelming physiological and evolutionary evidence forms "intent" is a philosophical question. If some agent "intends" us to a vegetarian diet, it also "intends" us to take nutritional supplementation or import food from far, far away to make up for all the chemicals we can't synthesize.
posted by 0xFCAF at 10:39 AM on March 11

"Intend" is not the word you'd want to use with this, unless you're a Creationist, or invoking the idea of Mother Nature, carefully crafting each critter by hand.

Barring that, humans have most of the traits of omnivores who eat meat. We've got the cellulated colon. Tons of enzymes for busting down meat. Etc. All of that evidence has been available for decades. You'll find a bunch of websites suggesting that we were meant to eat no meat, but they tend to only point out the features humans share with herbivores, like grinding molars. However, those are the same features other omnivores also share with herbivores.

The opposing view, some flavor of vegetarianism, veganism, lacto-ovo-whatever, opposes for a variety of reasons. Usually, the evidence in terms of how the body is supposed to work is pretty far down on the list compared to considerations like the ethical treatment of animals, carbon footprint, the "squick factor" and the like.

As to what to say to people who strongly hold the opposing view? "It's clear that we were designed to eat meat: probably less than Americans eat, but more than nothing. And, once you're past age fourteen, nobody is going to tell you that you can't have your pudding if you don't eat your meat."

Which I suppose is my question: Are you trying to get vegans off your back? Are you trying to make them enjoy a delicious rare bloody burger? Or are you trying to get your friends to go vegan? Are you trying to save the planet by getting rid of methane producing, grain devouring cattle? This needs a little more background, if you seemingly want debate tips.
posted by adipocere at 10:43 AM on March 11 [1 favorite]

The evidence is clear that man was a meat eater.

1. Our teeth are not optimized for chewing vegetables or fruit, as, arguably, were the paranthopoids (http://en.wikipedia.org/wiki/Paranthropus). Our jaws and jaw muscles are laughably weak compared to any plant-eater. Look at the sagittal crest on a gorilla, and you'll see what I mean.

2. Many studies have suggested that human beings are optimized as high-temperature endurance runners. Lack of fur, sweat glands, robust leg muscles, springy Achilles tendon, all argue for running down our food in the heat of the African sun. A human being in good condition can literally run a gazelle down ... in about 6 hours. Since we can't run fast enough to escape our predators (lions, leopards, hyenas), it's not an adaptation for protection. Gorillas, which do live on plants, can't run for more than short distances.

3. Our closest relatives, the chimps, kill and eat small animals whenever they can.

However the argument from "man's natural state" is a moral fallacy. Just because humans did a certain thing out of necessity when we were hungry in the wilderness 60,000 years ago doesn't mean we should do it now. Our natural state included a great deal of murder, rape and theft, too.
posted by musofire at 10:47 AM on March 11 [4 favorites]

"Intended" is a heavily loaded term here; the answer is going to depend on whose 'intent' you have in mind. Same thing with "Superior".

We evolved as omnivores, therefore can eat meat, and it takes special effort to get proper nutrition without eating meat. We also evolved with enough intellect and empathy that some people believe consuming meat is undesirable. Neither position is "correct" in any absolute sense.

What would you say to people who strongly hold the opposing view?

I would try to steer us towards the restaurants which have decent vegetarian entrees, so they don't have to get by with just a salad.
posted by ook at 10:50 AM on March 11 [2 favorites]

http://articles.webraydian.com/article12503-MK_Gandhi_on_Vegetarianism.html

"On examination of the structure of the human body leads to the conclusion that man is intended by nature to live on a vegetable diet. There is the closest affinity between the organs of the human body and those of fruit eating animals. The monkey for example is so similar to man in shape and structure and it is a fruit eating animal. Its teeth and stomach are just like the teeth and stomach of man, while those of carnivorous animals, as for instance the lion and tiger are entirely different."

Alongside this quote is also painted Gandhi's comparison of the physiology of meat eaters and vegetable eaters:

Meat eaters:

Have claws
Don't have skin pores - so perspire through the tongue
Have sharp teeth for tearing and no molars for grinding
Have an intestinal tract 3 times the length of the body - so meat can pass quickly, before rotting
Have very strong hydrochloric acid in the stomach

Vegetable eaters:

Have nails instead of claws
Perspire through the skin
Have no sharp front teeth and have rear molars for grinding
Have an intestinal tract 10-12 times body length
Have stomach acid 20 times weaker than meat eaters

posted by goethean at 10:52 AM on March 11

Humans have developed as omnivores. (But I'm still a vegan.)

Tell people who hold the opposing view that although you agree with them that vegetarian diets are generally more healthful, more ecological and more ethical, that using unfounded arguments for vegetarianism is just going to discredit other more convincing arguments, so they had better go read up before repeating bullshit.
posted by beerbajay at 10:54 AM on March 11 [5 favorites]

You might be interested in the research done by the Weston Price Foundation.

My own non-scientific study, done on myself: when I was a vegetarian, I was fat and sick all the time. Now that I've reverted to being an omnivore (with lots of protein) I've lost weight and am rarely sick. That's all the evidence I need to believe that the omnivore diet is the intended one for human-types.
posted by chez shoes at 10:54 AM on March 11

The monkey for example is so similar to man in shape and structure and it is a fruit eating animal.

Gandhi was a great guy and all, but I don't think he was a zoologist. Now, I'm not either, but many monkeys eat bugs and eggs and some moneys will catch and eat other monkeys. I believe they're omnivores much like us.
posted by GuyZero at 11:01 AM on March 11

one point that has always resounded with me, which is often overlooked despite being obvious, is the zeal with which true carnivores pursue and tear into their prey. man looks at 'roadkill' and grimaces for example, where to a carnivore it would probably look wildly appetizing. the sounds that would come with tearing into a live animal in the wild with ones canines would be debilitating to man, where again, a true carnivore is unphased.

in my experiences, very few people are content to talk about the characteristics of the meat that they eat, as they have names ('hamburger') and processes (like grilling) that serve to more or less conceal what it is at its core (the flesh of a dead animal). many people feel almost threatened by this, even in the absence of any threatrics as with a group like PETA. they will proudly renounce the organization (and subsequently the message and principles) for their so-called antics, but in the end are equally as offended by the information itself.
posted by austere at 11:04 AM on March 11 [2 favorites]

The monkey for example is so similar to man in shape and structure and it is a fruit eating animal.

That's just silly.

The chimpanzee, for example, is much, much more similar to man in shape and structure (and genes), and it is an omnivore.

As are humans, obviously, as witnessed by the fact that we (with exceptions who have made a conscious decision) eat animals, plants, and fungi at every opportunity, and have for as far back as the archaeological record shows.

If you want to be an herbivore, more power to you, but it's absurd to pretend it's your species' natural state.
posted by Flunkie at 11:05 AM on March 11

Well for one thing, the term "vegetarian" (of which I am one) is a human created word. It refers to a human who chooses to not eat the flesh (or products) of other creatures. A deer is not a vegetarian, it is an herbivore. Humans are not herbivores. We are omnivores. We eat everything (relatively speaking). A vegetarian diet is a choice, one that apparently we are the only species on earth that can make. There is no "intention" or "superior". Biologically speaking, humans can quite easily flourish on a vegetarian diet. So can bears, for example. They just dont get to choose.

On preview, the quote from Gandhi and its attendant comments are spurious at best. He was no scientist.

Look, I maintain that at least a mostly vegetarian diet is healthier than a diet heavy than that complemented by our prepackaged and chemically altered meat industry. But biologically, we are simply not herbivores. The key element here is we have the brains to make a choice and can chart that path even when our basic animal biology might seem to dictate differently.
posted by elendil71 at 11:06 AM on March 11

A vegetarian diet doesn't provide all the essential amino acids unless you're very deliberate or take supplements. There's no question that our species evolved as an omnivorous one and a vegetarian diet ignoring that fact takes serious health risks. ... it also "intends" us to take nutritional supplementation or import food from far, far away to make up for all the chemicals we can't synthesize.

I'm not a prostylitizing vegetarian by any means, and have no doubt we evolved as omnivores, since we obviously weren't making stone hide scrapers for harvesting berries. But it would be nice if people could try to not spread baldfaced untruths. It's trivially easy to eat all the essential amino acids on a vegetarian diet with neither any real thought nor long-distance transportation of foodstuffs; beans, grains, and seeds grow all over the world. Which doesn't mean that meat isn't an incredibly convenient, mobile, and self-preserving (while still alive) source of protein...
posted by Dr.Enormous at 11:08 AM on March 11 [8 favorites]

Humans are omnivores, however, technology has allowed some people to switch to a vegan diet. Without a B₁₂ supplement that comes from a technologically modified source, vegans would die, as there are no effective plant sources of the vitamin.
posted by 517 at 11:09 AM on March 11 [1 favorite]

one point that has always resounded with me, which is often overlooked despite being obvious, is the zeal with which true carnivores pursue and tear into their prey. man looks at 'roadkill' and grimaces for example, where to a carnivore it would probably look wildly appetizing.

This may resound with you, but it's terribly oversimplistic. There are a wide variety of diets among animals, including some that scavenge exclusively, some that scavenge never, and many that are in between.

Moreover, comparing us to (a made-up oversimplification of) carnivores, finding some difference, and deciding that we are therefore are herbivores is no less silly than saying that we are carnivores because our mouths don't water when we see grass.

I honestly don't get the debate. We're obviously omnivores; we eat plants and animals (again, with exceptions who have consciously decided against it). That's what "omnivore" means.
posted by Flunkie at 11:13 AM on March 11 [1 favorite]

Evolution only "intends" two things: survival and reproduction. The former requires energy and humans (along with our closest relative: chimps) are omnivores. If it is fair to use the word intention here then its obvious that humans can eat a whole range of foods for survival. The idea that they can only do one specific category of foods is a politicized idea that pure BS. The idea that there's some natural morality that translates into human society is equally flawed.

Im not sure what you are trying to justify, but this type of reasoning isnt convincing and ultimately a non-sequitar. For instance, humans can easily eat other humans. I could argue that our "natural intention" it simply to eat the weak.

I think its important to see how flawed your question and its assumptions are.
posted by damn dirty ape at 11:16 AM on March 11 [1 favorite]

What would you say to people who strongly hold the opposing view?

That the argument from teleology is absurd on its face. Nature has no "intent".
posted by mr_roboto at 11:16 AM on March 11 [3 favorites]

in my experiences, very few people are content to talk about the characteristics of the meat that they eat, as they have names ('hamburger') and processes (like grilling) that serve to more or less conceal what it is at its core

This is more of an American thing than a human thing - in China, there's no question that the fish head on your plate is the head of a fish. Even at a food court in a mall you can see animals being cooked and in their original shapes.

...try to not spread baldfaced untruths. It's trivially easy to eat all the essential amino acids on a vegetarian diet

If it's trivially easy, then people are remarkably bad at doing trivially easy things. For example:

"A placebo-controlled experiment found that vegetarians who took 5 grams of creatine per day for six weeks showed a significant improvement on two separate tests of fluid intelligence, Raven's Progressive Matrices and the backward digit span test from the WAIS. The treatment group was able to repeat back longer sequences of numbers from memory and had higher overall IQ scores than the control group"

If you don't consider cognitive impairment to be a problem, that's your call, but the evidence shows at least some vegetarians rounded up by a university weren't getting enough creatine to keep their brains going at full speed.
posted by 0xFCAF at 11:16 AM on March 11

which is often overlooked despite being obvious, is the zeal with which true carnivores pursue and tear into their prey. man looks at 'roadkill' and grimaces for example, where to a carnivore it would probably look wildly appetizing.

This is stupid.
posted by damn dirty ape at 11:18 AM on March 11 [1 favorite]

Lot's of vegetables, but not all vegetables, and fish are what at least some scientists claim made modern humans.
posted by caddis at 11:19 AM on March 11

in China, there's no question that the fish head on your plate is the head of a fish.

Also, Ted Nugent. And anyone who eats meat and doesn't know what part of the animal it comes from is... dumb? I mean, there's simply no way to be any sort of decent cook if you don't understand the difference between different cuts of meat. Any butcher shop has a really big diagram that illustrates pretty clearly what comes from where. The provenance of rump roast, spare ribs or head cheese is no mystery.
posted by GuyZero at 11:30 AM on March 11

As many have mentioned, "intent" is definitely the wrong concept. You're also likely to get a few anecdotes in here, such as chez shoes's, which really only proves that the diet that chez shoes chose as a "vegetarian" was insufficient for chez shoes.

Humans evolved eating a diet comprised primarily of vegetable matter, with meat where we could get it. There is a class of animals, obligate carnivores, that require meat in their diet. Cats, for instance, do not produce the amino acid taurine, which is found in meat. You cannot put a cat on a vegetarian diet, or it will eventually die. Humans can synthesize taurine in our bodies, and all essential amino acids for a human diet can be found in a vegetarian diet.

The advantages of meat include a high energy density, and a relatively high proportion of protein. The disadvantages of meat include high proportions of fat, including saturated fat, as well as cholesterol. Economically and environmentally, meat takes more money and energy to produce per-calorie, and as such should be considered a luxury rather than the staple that it has become in the American diet. There are also animal-welfare considerations given the state of agriculture in America and other developed nations, but this may not be a concern for you, and is beyond the scope of this discussion.

A vegetarian diet, like all other diets, does need to be balanced, and those who cut meat from their diets without proper rebalancing will find they lack iron and protein, and feel weak and sick. A well-balanced vegetarian diet provides plenty of these nutrients, especially if eggs and dairy products are consumed. Vegans can have a difficult time obtaining sufficient Vitamin B12, but there are vegan sources for that as well.

If you're looking for some sort of evidence or argument to "excuse" your meat-eating, "human nature" won't really cut it, since humans didn't "naturally" come to be nearly 7 billion in population, nor to build our own dwellings or drive cars. I am personally a vegetarian for my own reasons, but if you like meat, I'd say just eat it. Your reasons are your own business, and you shouldn't feel guilty for enjoying it. I would urge you to, if possible, consider patronizing local farms where you know the animals are well treated and fed. It might cost more, but grass-fed cows are said to produce tastier meat anyway. Reduce your consumption of meat, it really is kind of a "sometimes food," but if it's something you want to eat, go for it.
posted by explosion at 11:31 AM on March 11 [1 favorite]

...try to not spread baldfaced untruths. It's trivially easy to eat all the essential amino acids on a vegetarian diet

If it's trivially easy, then people are remarkably bad at doing trivially easy things.

Creatine is not an essential amino acid.

If you don't consider cognitive impairment to be a problem, that's your call, but the evidence shows at least some vegetarians rounded up by a university weren't getting enough creatine to keep their brains going at full speed.

From your link:

A study on young adults (0.03 g/kg/day for six weeks) failed however to find any improvements due to young adults having the highest functioning brains...The dose used in this study would be comparable to an individual taking ≈ 2.2 grams of creatine per day. Creatine may only be effective in improving cognitive processing in individuals who have initially low basal levels of brain creatine and/or individuals who are either permanently (i.e. disease, aging) or suffering from only temporary (i.e. sleep deprivation plus exercise) cognitive impairments.

Also, I now have your comment as evidence that shows some meat-eating human's brains are not operating at full speed.

To answer the question, humans are omnivores. The common ancestor we share with gorillas and chimpanzees was likely herbivorous and thus that primate was intended to not eat meat. But humans are omnivorous, and meat is part of some of our diets.
posted by trueluk at 11:32 AM on March 11 [1 favorite]

But it would be nice if people could try to not spread baldfaced untruths.

Likewise, it would be nice if people would acknowledge that vegetarianism has been an established dietary culture for thousands of years. The idea of it as some sort of modern contrivance is honestly just ignorant.

I'm not a vegetarian and I don't believe that there is any justifiable argument for strict vegetarianism except the ethical one, which I don't personally endorse but respect as an arguable viewpoint. Health and ecology can be argued in favor of the drastic reduction of meat in the diet but to eliminate it completely is a decision of ethics.
posted by nanojath at 11:33 AM on March 11

0xFCAF I think the key words from the actual study you quote are "45 young adult, vegetarian subjects". So they found that students don't eat right and that in those that are vegetarians that caused a problem? Not indicative of all vegetarians by a long chalk and not evidence for anything much beyond the fact that students don't eat right which I think we all knew.
posted by merocet at 11:36 AM on March 11 [1 favorite]

If it's trivially easy, then people are remarkably bad at doing trivially easy things. For example:

"A placebo-controlled experiment found that vegetarians who took 5 grams of creatine per day for six weeks showed a significant improvement on two separate tests of fluid intelligence, Raven's Progressive Matrices and the backward digit span test from the WAIS. The treatment group was able to repeat back longer sequences of numbers from memory and had higher overall IQ scores than the control group"

0xFCAF, you're deliberately stirring up a shitstorm. First and foremost, there's no knowing if they picked out vegetarians who purposely eat a well-balanced diet, or vegetarians who just happen to abstain from meat. If you took a sample from an overall deficient population, of course you'll see an increase in cognitive behavior! Let's not forget that those who participate in studies tend to be poor and in need of money, which often tend to be those who...can't afford balanced diets!

Most of the population, no matter their diet, is eating unhealthily, and is likely to be deficient in one aspect or another. This isn't evidence for a vegetarian diet being bad for humans, but merely evidence of how damned hard it is to eat a perfectly balanced diet given the abundance of cheap carbohydrates that industrialized food science has provided us. Creatine is synthesized from other amino acids, and since proteins tend to be more expensive than carbohydrates (white flour, sugar, etc.), the deficiency is inevitable. See also America's obesity epidemic.
posted by explosion at 11:50 AM on March 11 [1 favorite]

If you don't consider cognitive impairment to be a problem, that's your call, but the evidence shows at least some vegetarians rounded up by a university weren't getting enough creatine to keep their brains going at full speed.

You should read your own cite. It cites earlier research showing the same improvement in omnivores.
posted by Dr.Enormous at 11:55 AM on March 11 [1 favorite]

What would you say to people who strongly hold the opposing view?

I'd tell them that the argument itself is foolish. People can demonstrably live healthily to a ripe old age as omnivores or herbivores, so every argument is moot.
posted by coolguymichael at 11:56 AM on March 11

Aboriginal man's diet probably was probably the physiologically and spiritually healthiest. If you respect your meat and kill it yourself, you're unlikely to have more than you should.
posted by Joe Beese at 11:58 AM on March 11 [2 favorites]

I'd tell them that the argument itself is foolish. People can demonstrably live healthily to a ripe old age as omnivores or herbivores, so every argument is moot.

I would avoid using arguments that deny pretty much everything statistical analysis is based on. Just because there exist elderly omnivores and elderly herbivores does not mean omnivores and herbivores have equal average lifespans. By your logic, every argument against smoking is moot since some smokers live to advanced ages.
posted by DevilsAdvocate at 12:04 PM on March 11

Regardless of what you eat, it's probably not going to be very close to what our ancestors ate. Meat from modern livestock is pretty different from game and plants bred selectively for agriculture are very different from their wild ancestors.

We know that most apes eat mostly plants, but the consensus among many anthropologists is that meat allowed the leap in brain size that brought us to where we are now. Of course, I've read recent research delving into whether the leap was because of cooking or fermentation, both also processes that make calories more easily available for big brains.

In terms of hunter-gatherers, the ones that have survived until modern times have been omnivores, through the % of meat in the diet varies among groups. There is no archaeological evidence of vegetarian or vegan hunter-gatherers.

As far as the bonobo, the ape trumpeted as a model relative by many vegans, even they sometimes utilize animal protein.

If you are bored and want to read lots of stuff on the subject, Human Diet: Its Origin and Evolution edited by Mark Teaford has some good stuff including a breakdown chart of % calories from animals in known hunter-gatherer tribes. Loren Cordain's research is also interesting.

But while many of us try to eat like hunter-gatherers because of health reasons, in the modern world things have changed...even if you eat meat now, it's not the meat Grok the caveman ate, which was leaner, had a different fatty acid profile, and was not pumped full of hormones and kept in a tiny cage its entire life.

And from all I've read the story about hunter-gatherers tends to be they were in good health regardless of whether they got their fat from coconut or lion until the introduction of crap like cheese, white flour, and sugar.
posted by melissam at 12:09 PM on March 11

sorrenn: Does the evidence indicate that man was intended to eat meat, or is a vegetarian/vegan diet the superior and intended one?

The evidence indicates that if there was ever any kind of intention involved in the beginning of humanity as we know it, it was a hazy and obscure one, to the point where human beings disagree broadly and contentiously about it.

I'm not being dismissive. It's good to try to figure out what the best way to live is. I'm only saying that people have eaten all kinds of things over the centuries, and can rightly be called "omnivores."

As far as the best diet: if you're speaking in terms of moral quality, it seems to me that veganism wins out in most estimations. Even if you're like me, and you eat meat and believe that it's possible to eat meat while remaining morally in the right, eating meat always offers the temptation to do wrong, especially in our day. It's possible to be a carnivore without cruelty or maliciousness, but it is difficult. Whereas veganism (and vegetarianism, to a large extent) is free of this temptation.

But I have a feeling, given the way you asked this, that you're trying to determine the best diet in terms of physical health. That's a muddier question, I think. People have survived on all kinds of diets, from all-vegetabe to all-meat. I don't think the all-meat thing works very well, but people are pretty diverse; even people in the same family can have bodies that react better to fewer or more vegetables or meat. I don't think it's possible to proscribe one as "better for humans."
posted by koeselitz at 12:23 PM on March 11

Amongst animals the coyote, and perhaps regular dogs, are known as the great adapter. Look any place in the world and second only to humans, you will find dogs (made it to space!) and coyotes. In the states coyotes have pushed out native wolf populations and live even in our cities. For their diet see Food here.

The greatest adapters are humans. Like coyotes we eat the best available source(s) of food. Could be meat, could be vegetables, grain, etc. How 'best' is defined is left to the individual and whatever society passes to them. Natural selection takes care of the rest.

Fricken crows could give both of us a run for our money though. I'd say cats too but I don't think they care enough to try.
posted by jwells at 12:26 PM on March 11 [1 favorite]

This is what I recently said to someone I thought held the opposite view.

Vegetarianism is an ideological diet based on moral conviction, not on nutritional grounds. As would thus be expected, a diet founded on nutrition is more healthful than a vegetarian diet. But a diet based on eating whatever crap you feel like eating, is far less healthful than either of those. Most of us eat the latter diet, which makes a vegetarian diet very healthful indeed!

And because it involves paying some (as opposed to no) attention to your diet, vegetarians are generally also more nutritionally aware than others. But nutrition, biology, evolution, etc do not suggest a vegetarian diet, you need one extra step to get there; something in the form of "ought" - a value statement about the world. It might be related to carbon footprint, or the rights or suffering of animals, karma, land-use efficiency, world trade, there are many good reasons.

There is a non-"ought" path to vegetarianism - urban/suburban people who have grown up so sheltered and disconnected from their food and from nature that they have become highly squeamish and get icked out by an omnivorous diet. I put this in a different category because it is a peccadillo rather than a display of strength and conviction, and so does not command respect the way that other vegetarians do.

So in the sense of health and biology, a vegetarian diet is superior to no diet, and a nutritional diet is superior to both. In the sense of demonstrating conviction, the vegetarian diet is superior to both. It really depends what you're after.
posted by -harlequin- at 12:36 PM on March 11 [1 favorite]

Some vegetarians have the idea that a vegetarian diet is more "natural", less damaging. The reality is ironic: in most parts of the world it's only possible to eat a vegetarian diet because of high tech, especially powered transportation.

Fresh fruits and vegetables are available to us year-round, but that's because they're grown in greenhouses (kept warm using electricity created by burning coal), or shipped in from the tropics. In the US, our winter vegetables often come up from Mexico, hauled by trucks (burning diesel). A Vegan's diet is built on a foundation of fossil fuels.

Strictly speaking, one of the big benefits of meat is that fresh meat is available year round. All you have to do is go find something you feel like eating and kill it.
posted by Chocolate Pickle at 1:08 PM on March 11 [1 favorite]

Others have pointed out that there is no "intended" diet and that human beings can survive on a wide range of diets, that we're really quite scrappy omnivores at the end of it. But one other thing is that there are some arguments that it depends on the individual - ancient systems like ayurveda divide into different body types, or modern books like "eat right for your type" suggest that your preferred diet is based on what blood type you are. These examples may or may not have much basis, but the underlying thought, that different people thrive on different diets, still seems to have some truth to it. Some people really get weak when they try to go vegetarian, even when they really want to do it. Others find it easy or almost natural, and just sort of forget to eat meat most of the time because they crave the veggies.

Some of this is undoubtedly due to what they actually eat (most people will get weak just living off potatoes and pizza...) but it makes sense that different bodies, at different points in life, would need different things. Like your sense of humor or taste in music, your nutritional needs are tuned specifically to you and won't always match (though they'll be somewhere in the same ballpark as) other people's.
posted by mdn at 1:14 PM on March 11

Like most simians, we can eat a multitude of things. We generally adapt to whatever foods are most accessible in our environment, with varying physical and mental results (nutritional anthropology is a fun field to read in, if you're interested, and it seems like you may be).

Our brain development is currently thought to be partially from increased ingestion of Omega-3 oils, largely from fish. Who knows if that theory will bear out - these things are proffered and dumped on a seemingly weekly basis. Seems reasonable, on the surface, like many ideas of why we eat what we eat.

More to the point, our systems are built for an omnivorous diet, partially because of the variety of climates and landscapes we are capable of subsisting in. We can lean more in one nutritional direction over another and still survive - and even thrive - whereas many other creatures are restricted to one or two major food sources.

We can scavenge, hunt, and farm and are thinking creatures with the ability to choose our food sources based on complicated factors beyond "can haz". We can elect to do no harm and still thrive - which can mean humane meat-eating in addition to being meatless - which is a nice benefit for a species to have, to say the least. Our incredibly advanced understanding of nutrients gives us an advantage over every generation of human prior to ours, because we can look into our systems and determine which things we've become used to we can actually do without and which things we ignore we might need.

Current nutritional studies are advising a diet heavy in fruit and vegetables, plenty of legumes, moderate whole grains, occasional meat/other compact proteins, and sparing but regular amounts of healthy fats. And, of course, lots of water. This seems like precisely the dietary compromise our system has evolved to process most easily and healthily, and offers plenty of room for conscientious selection of our protein sources.
posted by batmonkey at 1:16 PM on March 11 [1 favorite]

one point that has always resounded with me, which is often overlooked despite being obvious, is the zeal with which true carnivores pursue and tear into their prey. man looks at 'roadkill' and grimaces for example, where to a carnivore it would probably look wildly appetizing. the sounds that would come with tearing into a live animal in the wild with ones canines would be debilitating to man, where again, a true carnivore is unphased.

Your imagination is running away with you when you describe animals finding something "wildly appetizing" or being "unfazed." Romantic anthromorphizations aside, how would you be able to know what a carnivorous animal feels?

in my experiences, very few people are content to talk about the characteristics of the meat that they eat, as they have names ('hamburger') and processes (like grilling) that serve to more or less conceal what it is at its core (the flesh of a dead animal). many people feel almost threatened by this, even in the absence of any threatrics as with a group like PETA. they will proudly renounce the organization (and subsequently the message and principles) for their so-called antics, but in the end are equally as offended by the information itself.

My experiences are very different than yours. Hang with a foodie crowd -- we generally have no problem discussing meat as meat and eating organs that look very organ-like. See also: the rest of the world. (I don't understand how grilling is obfuscating the source of the meat, unless the meat is ground. When I grill chicken parts, they look like chicken parts.) I won't derail the thread farther with my objections to PETA, but suffice it to say that it is not because I am upset by knowledge of the sources of my food.

sorrenn, regarding what to say to people who hold the opposite view -- if someone refuses to believe that our species evolved to be omnivorous, well, I don't know what would change their mind. It's not a fact that's in debate. But we evolved to survive, period. We live in a time where it is possible to choose what we eat based on preference, rather than simply chasing sustenance. That's okay, the same way it's okay to wash our hands with soap to avoid without being upset that we're betraying our human innate weakness to death from dysentery.
posted by desuetude at 1:40 PM on March 11

What would you say to people who strongly hold the opposing view?

Although this was likely not your intent, I find that those asking such a question often treat vegetarianism as a recent fad adopted by a small group of ideologues, rather than the standard diet for millions of people throughout human history.

Mefi people are almost always too smart for this, but the implication with phrasing a question this way is that you can suggest a vegetarian diet is unsustainable. Statements like "man evolved to eat meat" seems to suggest that not eating meat violates the basic functioning of the human body. (In the sense that man "evolved to breathe oxygen and consume water").

Again, not a shot at anyone here, just an observation I've made.
posted by Adam_S at 2:28 PM on March 11

"What would you say to people who strongly hold the opposing view?"

I would say "Apparently, we disagree." Beware of groupthink. Diversity of thoughts and ideas is a beautiful thing.
posted by 2oh1 at 2:50 PM on March 11

I think musofire brings up the best clue: that our primary anatomical specialization is to run down herbivores on the African plains. An efficient sweat gland system and little hair, except a thick, constantly growing mop on top to protect from the noon-day sun and eyebrows to channel sweat away from the eyes. Modern Bushmen can run down a giraffe over the course of a day, kill it, cut it up and run many miles home with it. All the other predators catch their prey in a fast dash or they team up like a relay team to run an animal down. Humans do it the slow and steady method, which is unique to our species.

If you can accept the premise that there's a basic body plan for the higher primates and each species diverges from that basic plan, then I don't see how anyone could argue that we diverge the most from that basic body plan in the structure feet, unable to grasp things but giving us the unique ability to run upright for very long distances. Bipedal apes (presumably our forebears) have been traveling that way for a few million years, even before developing extremely large brains and making complex tools.

I don't eat much meat myself because I don't like or trust modern factory farming methods, but I imagine our early lifestyle was omnivorous, mothers foraging plants and insects, suckling the babies, other troop members running down food, pulling it apart, eating it raw, sharing it with the foraging members, getting liver flukes and tapeworms. Our bedding was full of skin parasites. Average life span about 30 or 40 years. I don't think there was ever some" Golden Age" when humans ate the "right" food and lived without disease.
posted by bonobothegreat at 4:41 PM on March 11

nanojath:
Likewise, it would be nice if people would acknowledge that vegetarianism has been an established dietary culture for thousands of years. The idea of it as some sort of modern contrivance is honestly just ignorant.

Citation, please? 'Cuz one of us is just ignorant.
posted by IAmBroom at 9:31 PM on March 11

To paraphrase Hobbes, life in the state of nature was solitary, nasty, brutish and short.

Look, I'll cop right off to being a vegetarian, lifelong. I've heard and had all these arguments again and again.

As far as I know, there's no data that shows vegetarianism to have a predictable effect on common metrics of health in a conclusive way. There are some health risks, sure, but arguing that some random vegan having a vitamin deficiency means that cutting meat out of your diet is unhealthy is the same as arguing that Morgan Spurlock proved our bodies can't handle meat. We're "designed" to eat everything from grubs to humans (aside from that nasty prion bit), just like kids who need eyeglasses are "designed" to die on the veld.
posted by klangklangston at 10:16 PM on March 11

Citation, please? 'Cuz one of us is just ignorant.

Uh, India? Jainism? Buddhism? Vegetarian diets are pretty core beliefs for these religions (not every Buddhist, true, but plenty of them) and both religions predate Christianity by a fair bit, so I'd say that vegetarianism is hardly a new idea.
posted by GuyZero at 9:41 AM on March 12 [1 favorite]

seconding melissam and batmonkey...Here is another cite..

"Based on new insights into the behavior of chimps and other great apes, our now extinct human ancestors, and existing hunting and gathering societies, Stanford shows the remarkable role that meat has played in these societies. Perhaps because it provides a highly concentrated source of protein--essential for the development and health of the brain--meat is craved by many primates, including humans. This craving has given meat genuine power--the power to cause males to form hunting parties and organize entire cultures around hunting. And it has given men the power to manipulate and control women in these cultures. Stanford argues that the skills developed and required for successful hunting and especially the sharing of meat spurred the explosion of human brain size over the past 200,000 years. " From Stanford, C.B.: The Hunting Apes: Meat Eating and the Origins of Human Behavior.
posted by shr1n1 at 6:26 PM on March 12

Citation, please? 'Cuz one of us is just ignorant.

You know, even the bible has a little veggie moment in that Adam and Eve were vegetarian in the garden of Eden:
God said, "See, I have given you every plant yielding seed that is upon the face of all the earth, and every tree with seed in its fruit; you shall have them for food. And to every beast of the earth, and to every bird of the air, and to everything that creeps on the earth, everything that has the breath of life, I have given every green plant for food." (6) And it was so.

According to the straight dope it's not until after the flood that they're actually allowed to eat meat. So in the garden, they just eat fruits and nuts, like Jains, not even killing plants but just accepting the bounty that falls to the earth, but in the garden this is plentiful; then God curses the ground and sends them out telling them they'll have to toil and work and eat the plants themselves, and after the flood, they eat animals. All during this time the lifespan of man decreases and his interaction with God becomes far less common...

So christians could certainly interpret vegetarianism as closer to God. And if they understand heaven or the resurrection or whatever as a return to paradise, presumably that's vegetarian as well.
posted by mdn at 9:39 AM on March 13

mdn, if a Bible story from Genesis qualifies as sociological dietary evidence, then Greek mythologies prove humans can be impregnated by swans, bulls, and showers of gold.

Please, we are trying to discuss facts here, not your particular religious beliefs.
posted by IAmBroom at 3:02 PM on March 13

GuyZero: OK, you've got me there. I was ignorant that Buddhism and Jainism were that old.

However, "India" is not a religion, nor is it an exclusively vegetarian society. Only certain sects of Hinduism (which is what I suspect you meant by "India") are vegetarian.

Ironically, the poor, who can least afford meat, are the least likely to be vegetarians. It is the upper classes that favor the stricter vegetarian sects, according to my Indian coworkers.
posted by IAmBroom at 3:02 PM on March 13

I have no religious beliefs; I was just providing some evidence that the idea of vegetarianism predates the last century.

I thought it obvious enough those mythologies were not literal, sorry if that confused you. The point is: they were understood as describing how the world ought to be vs how it is when it is full of sin. At some basic level, the judeo-christian mythology does not see meat-eating as in harmony with an ideal world. So to suggest that no one thought of abstaining from meat until the last century is ridiculous. It may have become more popular in recent times since we have so much freedom and so many choices now, but the basic impulse goes way back...

I'm not trying to say that's good or bad or anything - I was just pointing out that the discomfort with meat is not some new modern sickness.
posted by mdn at 8:32 PM on March 13 [1 favorite]

That the argument from teleology is absurd on its face. Nature has no "intent".

That's an ideology, not a point of fact.
posted by goethean at 7:58 AM on March 14