Humans are natural meat eaters (or are they)

[dong20]

An LPSG member and I discussed this way back because we disagreed on the subject of wheher Humans choose to eat meat and are not thus Omnivorous by nature or the reverse. I long ago said I would start a thread.

Yes, I know the strict defintion of Omnivore is debatable but I'm using it here to as a genral label for adaptation not choice e.g. vegetarian or vegan. There are several other '-ivores' of course and as Humans we pretty much have the lot covered.

Does the evidence suggest Humans have evolved as Omnivoires? For, while we can eat both meat and vegetable matter and other things, cooked or raw, our biology is not fully adapted to one to the exclusion of the other - i.e that we don't posses the full range of adapations typically defining Carnivores or Herbivores. Or, does over 2m years of eating meat combined with those partial adaptations suggest otherwise.

After all, few mammals are entirely selective and one could argue most could be considered omnivorous - if you define that by being able to eat both meat and vegetable matter and not die then yes I agree, within reason. But is that enough? I'm sure not everyone at first thought would think of; Wolves as herbivores - because they do eat plenty of plant material or Chimps as carnivores - because they do kill and eat meat.

To start off, here a a couple of opposing viewpoints on the subject of Human meat eating being 'natural'.

Anti:
How humans are not physically created to eat meat

Pro:
Comparative Anatomy Updated. Humans--Omnivores or Vegetarians?

 

[Gillette]

I would say omnivorous based soley on dental structure. We have molars for grinding/mashing, incisors for choping/cutting as well as canines for ripping/tearing.

Without checking for reference material at this time I'm going to say that the canines are a fairly clear indicator that we evolved to eat meat. Most herbivores have incisor teeth for cutting through the plants they eat but I can't think of any off the top of my head that have adapted dentition for ripping flesh.

I had an incompletely formed thought using psychology but I'm just going to leave it in my head to percolate.

 

[SpoiledPrincess]

We have incisors intended for cutting, our eyes are on the front of our head as those of predators usually are to give us binocular vision, and we have one stomach unlike most herbivores. There are many animals which are mainly carnivores but can also digest vegetable matter and like them our digestive system isn't set up to break down the cellulose in vegetable matter as effectively as the digestive system of a herbivore.

 

[dong20]

We have incisors intended for cutting, our eyes are on the front of our head as those of predators usually are to give us binocular vision, and we have one stomach unlike most herbivores.

Without checking for reference material at this time I'm going to say that the canines are a fairly clear indicator that we evolved to eat meat. Most herbivores have incisor teeth for cutting through the plants they eat but I can't think of any off the top of my head that have adapted dentition for ripping flesh.

It's a common 'proof' but have a look at this, the writer makes a strident dismissal on the tooth issue. It's not entirely objective for sure but interesting nonetheless:

http://michaelbluejay.com/veg/natural.html

Interestingly, some of the most strident arguments against Humans being natural meat eaters appear to come from those who object on grounds other than (or sometimes in addition to) scientfic ones, often moral. I don't think I have seen as many arguments in favour of meat eating being natural though not necessarily a good thing as I have from it being unnatural and also definately a bad thing. Often this is done while showing picures of wonderfully fit looking vegans, many of whom probably exercise and work out to the point of obsession.

However, to be even handed; have a look at the table here.

Some of the main things that made me think hard are vitamin A detoxification, colon function and stomach acid strength. I'm still not convinced that human meat eating is purely a social adaptation and while I do think we are overall probably better suited to eating predominately plant material than meat the question is does that preclude us being Omnivorous by nature or are we purely social omnivores.

Anyway, this thread, at least for me is not about the relative merits of meat eating but whether Humans do so by desire or design. I think there are compelling arguments on both sides and while I fall on the 'natural' side of the argument I can appreciate the strength of the evidence the other way.

There are many animals which are mainly carnivores but can also digest vegetable matter and like them our digestive system isn't set up to break down the cellulose in vegetable matter as effectively as the digestive system of a herbivore.

I agree, and many of the pro herbivore arguments are rather selective; relying on the argument that because Humans are primates and primates are Herbivores, therefore Humans, being similar genetically to primates we must also be herbivores. They often choose to ignore the fact that while Gorillas*, Orangutans* and Chimps* are predominately herbivores they are not exclusively so.

It's something of an association fallacy; "People eat more ice-cream in summer, there's more crime in summer - therefore ice-cream causes crime."

* Another common fallacy is that Orangutans and Gorillas are nearer to us gentically than any other species who they say are 100% Vegan thus we share behaviours such as diet, sorry, but not so on both counts. We are closer to Chimps and monopos who do show (albiet limited) omivorous, if not carnivorous tendencies. Gorillas have been observed intentionally eating incects (ants), in the Virunga region of Rwanda and Zaire (DRC).

If it were possible to be certain that chimps eating termites, hunting and eating other monkeys and gorillas eating ants etc are doing so simply because they feel like a change for dinner as opposed doing so to satisfy a dietary, thus a (one might reasonably assume) natural requirement I'll be far more open to change my view.

In other words the argument; we're not carnivores - therefore we're herbivores. I'm not convinced it's quite so black and white.

 

[Ethyl]

Some of the main things that made me think hard are vitamin A detoxification, colon function and stomach acid strength. I'm still not convinced that human meat eating is purely a social adaptation and while I do think we are overall probably better suited to eating predominately plant material than meat the question is does that preclude us being Omnivorous by nature or are we purely social omnivores.

Anyway, this thread, at least for me is not about the relative merits of meat eating but whether Humans do so by desire or design. I think there are compelling arguments on both sides and while I fall on the 'natural' side of the argument I can appreciate the strength of the evidence the other way.

Interesting articles. I'll go out on a limb and say i'm 75% convinced that (human) herbivores are the result of social adaptation, not the other way around. If our ancestors were meat eaters and our teeth were designed for such, that's one argument, but we don't have to expend so much energy hunting for food anymore and we don't need the fat reserves to survive the long, cold winters. Eating meat is fun but not necessary for survival as it once was.

 

[Wyldgusechaz]

Interesting articles. I'll go out on a limb and say i'm 75% convinced that (human) herbivores are the result of social adaptation, not the other way around. If our ancestors were meat eaters and our teeth were designed for such, that's one argument, but we don't have to expend so much energy hunting for food anymore and we don't need the fat reserves to survive the long, cold winters. Eating meat is fun but not necessary for survival as it once was.

What do chimpanzees and bonobos eat?

I read once we developed opposable thumbs inorder to pick fruits, seeds and BUGS for dinner.

I love a good steak. Try Gibsons in Chicago. However I just can't digest it very well anymore. I almost always have to down a Pepsid after eating meat.

I couldn't open the links and this might have been mentioned there but there are some essential fatty acids that we have to get from our diet to survive and they aren't found much in red meat. Salmon and seed oils have them.

 

[LouisVauban]

There's also a lot to be said for Blood Type... The book "Eat Right 4 Your Type" is fascinating read and true!

My body doesn't digest uncooked vegetables well. But, meat is no problem. Cooked veggies are ok. A homeopath suggested to me that salads were of little use to me, as my body doesn't break down the uncooked vegetable. While vital nutrients are lost in the cooking process, my body actually retains a higher percentage of nutrients from the cooked version.

The source for the book suggests that different blood types evolved from prehistoric tribes... some ancestors were meat-eaters, some were omnivorous.

So... which came first? Seems like a Chicken and Egg controversy, with no true answer.

One Filet Mignon, please... Medium Rare!

 

[madame_zora]

Interesting articles. I'll go out on a limb and say i'm 75% convinced that (human) herbivores are the result of social adaptation, not the other way around. If our ancestors were meat eaters and our teeth were designed for such, that's one argument, but we don't have to expend so much energy hunting for food anymore and we don't need the fat reserves to survive the long, cold winters. Eating meat is fun but not necessary for survival as it once was.

Add me to your 75%, I'm right there with you. I think a lot of issues that have previously been issues of practicality are now being issues of morality and choice is because we are in a time of luxury- we HAVE the luxury of making decisions about these things bsaed solely on morality, not need. We've developed as carnivores and omnivores, so now that we're here, what do we choose? We can consider how much land it takes to feed an animal to slaughter to feed a person, and if it wouldn't be better and more efficient use of land to just feed the person directly? We can consider what it really means to "farm" animals, and ask ourselves how we really feel about that (if any way at all). Clearly vegetarians and vegans have been around for long enough that we know it's possible, so the question is really only whether it's a good idea.

I like to err on the side of caution. I believe that my time is best spent alleviating suffering to the best of my ability, then I'd rather not cause the death of something if I don't need to. While even killing a plant causes a death (which means gluttony is bad, regardless of point of view on religion/philosophy), the plant likely suffers less than an animal would, or is at least less aware of it. My daughter has prompted me to return to these standards, as I raised her vegetarian for much of her life, but had fallen out of it for a while. She's gone on to going vegan- I'm not there yet, but it could happen.

I see this NOW as just a social choice. Neither is right or wrong in general, just right or wrong for the individual.

 

[dong20]

Interesting articles. I'll go out on a limb and say i'm 75% convinced that (human) herbivores are the result of social adaptation, not the other way around. If our ancestors were meat eaters and our teeth were designed for such, that's one argument, but we don't have to expend so much energy hunting for food anymore and we don't need the fat reserves to survive the long, cold winters. Eating meat is fun but not necessary for survival as it once was.

I think I'd agree that modern (modern as in now) man is a social omnivore in that it's choice not necessity which drives meat eating. As Zora said, today there is little or no absolute requirement for us to eat meat to live, except perhaps in rare or specialised circumstances.

Modern Humans (as a species) are genetically identical to what we were when we 'evolved' so it could be argued the same social omnivore status applied then as now. However, I'd say physical and environmental factors which for the most part no longer apply will have forced early man to behave and thus eat differently, though possibly eating less meat then than now unlike today doing so may have made the difference between survival or not. On such grounds I have to say I'm still in the omnivore by nature camp even if not by virtue of physical adaptation, or at least one foot is....

The more I have read the more about this the more I'm leaning toward a view opposite to the one I had when the subject came up many months ago.

 

[SomeGuyOverThere]

Meat tastes good and it doesn't make me sick.

Is there any stronger arguement than that?

 

[JustAsking]

We have a herbivore ancestor not too far back. Our carnivorous traits along with our dairy eating and grain eating traits are new enough to be not completely evolved. So its not surprising that you can find both herbivore and carnivore traits in our makeup.

Our teeth have evolved in a very obvious and clear fashion from that of our last herbivore ancestor and so has the size and nature of our stomach and digestive system. From those changes also came changes to the shape of our rib cage, etc. Herbivorous primates have very large stomachs and different shaped rib cage to accomodate it and protect it.

In terms of food energy, our evolution into carnivores was essential for evolving a big brain, since the energy requirements are very high (some 20% of our food energy is used by the brain) for having such a large brain.

I am just now reading a really fascinating book called "Before The Dawn", about human evolution in recent prehistory.

 

[monstro]

I've been vegetarian for almost 7 years and have been vegan for about 7 months. Eating a plant based diet definitely agrees with me. I'm in great shape--I'm 40 years old but look 15 years younger than that. I feel like a teenager, in fact. All around, I feel less sluggish, depressed and weighted down than when I ate meat.

I was virulently anti-vegetarian throughout my teens, twenties, and early thirties but gradually came to have a change of heart. And I'm glad I did. (I was also a chain-smoking alcoholic for much of that time, btw!) When I was an omnivore I was plagued by chronic indigestion, diarrhea and bleeding hemorrhoids After cutting out meat I have never had so much as an upset stomach.

I don't presume that my experience speaks for the whole of humanity since the dawn of time, I'm just saying that's my experience. :smile:

 

[Love-it]

In my personal experience women digest grains and vegetables easier than men and men do better with high protein diets.

 

[dong20]

In terms of food energy, our evolution into carnivores was essential for evolving a big brain, since the energy requirements are very high (some 20% of our food energy is used by the brain) for having such a large brain.

Along that line, you may find this interesting.
There's something fishy about human brain evolution

 

[almost10]

Meat tastes good and it doesn't make me sick.

Is there any stronger arguement than that?

You enjoy the taste and don't get sick only because you cook the hell out of that meat. Try eating some raw meat if you want to talk natural.

 

[almost10]

[FONT=verdana, arial]For any human being to describe himself as a carnivore is just plain ridiculous.

[/FONT][FONT=verdana, arial]Humans are not and have never been carnivores. A lion is a carnivore as is a wolf, as is a tiger, or a shark. Carnivores eat live animals. They stalk them, they run them down, they pounce, they kill, and they eat blood-dripping meat at body temperature. Nature - brutal red in tooth and claw.[/FONT]
[FONT=verdana, arial]
[/FONT]
[FONT=verdana, arial]I've never met a human that can do that. Yes we found ways to run down animals and kill them. In fact, we've come to be rather efficient at the killing part. But we can't eat the prey until we cut it up and cook it - and that usually involves some time between kill and eating. It could be an hour or it could be years.[/FONT]
[FONT=verdana, arial]
[/FONT]
[FONT=verdana, arial]You see, our meat-eating habits are more closely related to the vulture, the jackal, or other carrion eaters. This means that we can't be described as carnivores. We are better described as necrovores - or eaters of rotting flesh.[/FONT]
[FONT=verdana, arial]
[/FONT]
[FONT=verdana, arial]Consider that some of the beef that people eat has been dead for months and in some cases for years. Dead and hanging in freezers, full of uritic acid and bacteria. It's a corpse in a state of decomposition. Not much that can be said to be noble about eating a cadaver.[/FONT]
[FONT=verdana, arial]
[/FONT]
[FONT=verdana, arial]But a little dose of denial allows us to bite into that Big Mac or cut into that prime rib. But that one 16-ounce cut of prime rib is equal to a thousand gallons of fresh water, a few acres of grass, a few fish, a quarter acre of corn, etc.[/FONT]


[FONT=verdana, arial]Excerpted from:[/FONT]
[FONT=verdana, arial]Captain Paul Watson
Founder and President of the Sea Shepherd Conservation Society (1977-
Co-Founder - The Greenpeace Foundation (1972)[/FONT]

 

[SpoiledPrincess]

Lots of people eat raw meat - beef carpaccio, steak tartare, when I was at school and we were kids making sausage rolls we'd all wolf down the raw sausage meat (no one ever told us not to at that age) doesn't make me sick whether it's cooked or not.

 

[almost10]

Yikes. Raw pork is fine for the kids?

 

[SpoiledPrincess]

Ick no, it's supposed to be full of tape worms, but no one told us in cookery class.

 

[dong20]

[FONT=verdana, arial]For any human being to describe himself as a carnivore is just plain ridiculous.

[/FONT]

In biological/physical/evolutionary terms I agree. In a dietary/social adaptation sense, I don't. After all the definition of carnivore from the latin - meat eater; from carne meaning 'flesh' and vorare meaning 'to devour'. This makes no reference to how that meat is obtained. It's these two aspects that get intertwined.

[FONT=verdana, arial]

Humans are not and have never been carnivores. A lion is a carnivore as is a wolf, as is a tiger, or a shark. Carnivores eat live animals. They stalk them, they run them down, they pounce, they kill, and they eat blood-dripping meat at body temperature. Nature - brutal red in tooth and claw.

[/FONT]

[FONT=verdana, arial]You see, our meat-eating habits are more closely related to the vulture, the jackal, or other carrion eaters. This means that we can't be described as carnivores.

[/FONT]

Many if not most of the notable carnivores; Tigers, Lions and so on are not above scavenging when an opportunity arises. Vultures, hyenas and jackals are typical examples of scavengers and while many will hunt, it's not all species typical MO, they are all however unquestionably carnivores.

As far as carnivores being defined by being hunter killers; well, that's certainly the popular characterisation and while it's got much validity it's not definitive. Not all carnivores hunt and not all hunters are carnivores - many are primarily scavengers. Vultures for example - though it's not unknown for them to kill sick and weak animals. They are carnivores based on diet and have evolved many biological adaptations to enable them to survive on rotting flesh.

We are better described as necrovores - or eaters of rotting flesh.

For the most part scavengers are opportunistic and that hardly fits modern human behaviour - eating roadkill is an interesting 'niche' but it's hardly mainstream. Prehistoric humans probably fit that characterisation much more closely than we do. We're certainly not carnivores in the hunter killer mould, I don't think anyone would deny this - but that doesn't preclude us being in part carnivores based on diet.

[FONT=verdana, arial]

But a little dose of denial allows us to bite into that Big Mac or cut into that prime rib. But that one 16-ounce cut of prime rib is equal to a thousand gallons of fresh water, a few acres of grass, a few fish, a quarter acre of corn, etc.

[/FONT]

I don't think it's as much denial as misconception. Eating meat doesn't make one a carnivore any more than eating salad makes one a herbivore.