Are humans meat eaters or vegetarians by nature?

Cecil's Columns/Staff Reports
81

http://carbs-information.com/digestion-of-carbs.htm

http://nfs.uvm.edu/nfs-new/activities/tutorials/lipid.html

It’s fairly complex, these three links should give you an idea. The body runs on glucose, which is it’s fuel basically. (sugar starch)

Fat is a storage medium, that must be converted to glucose, which involves more energy. The tutorial link will show you not only how fat can clog arteries, but also the process it uses to be converted to glucose.

Protein too can be converted to glucose, but the process is again far more complex then simply eating glucose.

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Also worth note.

“The process begins in the mouth when an enzyme in saliva (amylase) begins to break down starchy carbohydrates.”
http://carbs-information.com/digestion-of-carbs.htm

Evolutionary mechanism for dealing with starch.

Worth note in this conversation.

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What about plants that aren’t carbs? Are you suggesting we should live on all carbohydrate diet?

Second, of course we’ve evolved to eat starch. There’s so much of it that it would be truly weird if we couldn’t utilize it as a food source. I maintain we have also evolved to eat animal protein.

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No not trying to suggest anyone change their lifestyle habits, this is an academic question in my mind.

But now we have biological adaptation to a plant starch source of food, and technological adaptation towards animal foods.

 There are still the protein and fat requirements, and key nutrients, wouldn't see anything skipping them being to biologically successful.

The post this is all based on is 20 years old.  I think since that time there is quite a bit more to be said on the natural diet of humans.  The issue just seemed to me to have grown in complexity in the past several years.
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What you call a “technological adaptation” dates back (Off the toppa my head) at least to Homo Habilis. Again, tool use and fire making are as much a part of Homo Sapiens as fangs and packs are a part of Canis Lupus.

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http://www.phillyarchaeology.org/news/inq101507.htm

I tend to view agriculture as the fuel of civilization. Starch crops built empires, not hunting and gathering. Co-operative hunting did not need us to know the seasons, keep records, all the things that make us the knowledgeable folks we are today. Farmers would have to learn year long patterns and shifts in the environment to successfully grow crops.

Only a small group can depend on hunting in a given area, till the game runs out. The adaptation to starch must have come with the availability of starch foods, only through farming. I’m suggesting this is where that adaptation took place. Modern man.

There are no strong biological adaptations to meat, they are all technological. Not seemingly significant enough for nature to select for. Nobody gets " health conditions" from rice.

But there is more.

http://www.fasebj.org/content/13/3/559.full

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Which is why we’ve been keeping and breeding livestock for so very long.

So, according to you, the adaptation to starch came only with farming. But we know that fire making and tool use came far before that. Wouldn’t that suggest we’ve evolved to be omnivores?

This seems to be ‘moving the goal posts’. You’ve gone from saying we have no adaptations to eat meat, to saying we have no “strong biological adaptations”. Define the term “strong biological adaptation”. Our dentition is that of an omnivore. Our digestive tract length relative to our body length is that of an omnivore.

I could not disagree more strongly.

You have a cite for that?

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Some cultures did have livestock some didn’t arguably the successful ones did, and adapted to the diseases that came with it pox, ect ect. the civilizations that cultivated corn, I don’t think ever kept livestock, though I think the Middle eastern egyptian ones did. You can check if you like.

It would suggest if anything we have evolved from that, to be starch eaters. Historically wealthy people have used the extra grain/crops to feed livestock animals.
But it hardly seems a broad cultural staple. Again feel free to check it out if you like.
On then a misunderstanding, through out the thread I’ve been pretty clear on technologies role, and the biological issues caused by meat intake, being indicative of a lack of adaptation.

Please name the specific adaptations, or evidence, perhaps enzymes that break down animal lipids , something of that nature.

The lack of a source is more telling then the existence of one, or any controversy what so ever concerning the negative health impact of rice.

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There is no difference between an “animal lipid” and a “plant lipid”. As far as our body is concerned, there are only saturated fats, mono unsaturated fats, and poly unsaturated fats. True, animal products have more saturated fats then plant products do, but over all, it comes down to amount eaten over all.

As for enzymes, the human body is extremely good at getting every useable calorie out of a food source, no matter the source. Read this Wiki article on the digestive enzymes, and you will see how well the body digests food. Of interesting note, about the only thing humans can not digest is cellulose, which is the major starch in plants, and a major component of plant cell walls. That is the reason herbivores have a mouth full of molars to grind the food, and mechanically break cell walls instead of using an enzyme. This is the reason you can tell you ate corn the day after you ate it :slight_smile:

Cellulose is just glucose molecules that are connected by a beta bond instead of an alpha bond like regular starch.

Oh, and the only thing that is in animal based food and not in plant based is Cholesterol. Cholesterol is only made in animals (plants make look-alikes called stenols), and so is only in animal products. Most of the cholesterol in the body is produced in the liver, about 80% is produced in the body, only about 20% comes from food. This is because cholesterol is an important component of animal cell membranes (along with being a precursor to many other things like hormones and bile). It is interesting that the body can absorb cholesterol from the intestines, since it is only in animals. That means the body has an adaption to digest something that is ONLY in animal based foods, and NOT in plants.

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Ah ha! So your suggesting that our bodies have adapted a mechanism to take animal cholesterol in the intestine and put it into our blood stream as a supplement?

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Can you elaborate a little bit on LDL vs HDL? My very limited understanding is that the type we produce in our liver HDL is good. The other type LDL being bad. To much resulting in something called Atherosclerosis, I’m assuming LDL comes from animal foods.

Do you know much more about this or can you elaborate on why supplementation would be advantageous.

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Have you seen what passed for a banana before we bred the heck out of them?

My emphasis.

I’d pick the raw gazelle, thank you very much.

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First, even pure carnivores don’t have much in the way of “strong biological adaptations to meat” outside of stuff like claws and fangs that are easily superseded by even simple technology. Carnivores have short, simple digestive systems because meat is easy to digest; even herbivores can digest it. It’s the herbivores who have elaborate digestive systems.

Second; for humans tool use is as natural to us as using our teeth or hands; we’ve used tools longer than we’ve been human. So excluding the use of tools and fire is what is “unnatural”; even the most primitive and resource impoverished tribe has had those.

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“Our anatomy is clearly unsuited to deal with animal matter in the diet, however our digestive chemistry can deal with animal tissues and obtain some nutrition. But this does not indicate biological suitability or desirability. Cattle, which are herbivorous ruminents may eat many insects while they feed, chimps may occassionally kill and eat a small monkey. A pet cat may eat bread and margarine. So what? Are cattle to be defined as insectivores or omnivores, or opportunistic feeders? Is the pet cat an opportunistic feeder? Certainly, and the chimp an opportunistic feeder? Why not. None of this distorts taxonomy or suprises the biologist. All herbivores will be able to process animal protein to some degree or other since all protein is biochemically related. It is possible with modern processing methods to produce a “cat food” derived solely from plant material and non-animal matter that will keep a cat alive. Is this a herbivorous cat? No, it is a domestic animal eating an industrial diet. Higher lifeforms display a broader range of behaviours, and feeding behaviour simply reflects this, but does not reflect our true biological feeding requirements.”

“Of course tradition is not scientific, and the practice of humans eating meat is old, but has nothing to do with what we are biologicaly equipped to feed upon. We ate meat to survive, now we eat it out of habit and not need.”

http://www.tierversuchsgegner.org/wiki/index.php?title=Taxonomy

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Agriculture occupies, at most, 10,000 years out of a multi-million year history. Saying that’s somehow the most significant part of our biological history is like saying the entire purpose of the Eiffel Tower is to hold up the skin of paint on the very topmost point of the structure.

On top of that, archeological evidence very clearly shows a deterioration of health of early agriculturalists compared to nomads of the same period. The early farmers were shorter, their skeletons show evidence of malnutrition disorders, they have more tooth decay, and so on.

All humans require vitamin B12 to live, and the only natural source of that is animal flesh or milk. While it takes a long time to reach a fatally low level of B12 it will, inevitably, happen unless supplements - which until recently were all animal-derived - are taken.

This would seem to indicate that humans require a certain minimal level of food from animal sources.

There’s beriberi, which used to be strongly correlated with the consumption of white rice. (Now we know why and can remedy the problem)

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Yes, they did - dogs, guinea pigs, llamas, alpacas… Please do some more research on your chosen topic.

What you don’t seem to get is that technology IS the human adaption, or rather, the hominid adaption as technology pre-dates H. sapiens. We do some of our food processing externally, as opposed to all internally

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The liver produces BOTH forms of cholesterol. What’s really important is the ratio of LDL to HDL, which is why doctors are getting away from the “bad” and “good” descriptors. You actually need some of both, just more of one than the other.

BOTH forms are also found in animals. Again, it’s the ratio of one to the other than is important, and an animal that exercises regularly tends to have a better ratio of LDL to HDL, which is why lean meat (which usually implies a more active animal) is usually viewed as healthier than fatty meat (which implies a sedentary or even obese animal)

Cholesterol levels that are too low - while rare in modern society, they’re usually associated with starvation - can be just as unhealthy as those that are too high, as cholesterol is a vital component of many if not all hormones as well as all cell membranes. Deficient cholesterol can result in low levels of all the body’s hormones, which can result in all sorts of widespread effects and deficiencies. If your body had no cholesterol it couldn’t properly utilize vitamins A, D, E, and K - which would be fatal. The myelin sheath around all of your nerves, without which they cannot function, is rich in cholesterol. It is the precursor to bile, without which NO fats can be processed by the body, whether animal or plant origin.

Human breast milk contains cholesterol - clearly it’s a vital and normal part of the human diet.

Cholesterol is vital to the human body. The problem is not cholesterol, it’s having too much cholesterol. That whole “too much of anything, even a good thing, is a bad thing” concept.

Just so you know - having cholesterol that is too low is associated with (as noted) malnutrition/starvation, liver disease, overactive thyroid, underactive adrenal glands (they need cholesterol to produce their normal glandular products, so too low means they lack needed raw material), Marfan’s syndrome, and leukemia (and possibly other cancers). There are a couple of genetic diseases that result in very low cholesterol levels - abetalipoproteinemia, which leads to mental retardation, stunted growth, muscle weakness, slurred speech, coordination problems, difficulty walking, and gradual blindness. Then there is Smith-Lemli-Opitz syndrome, which comes with malformations of the heart, lungs, kidneys, digestive tract, genitalia, and mental retardation along with abnormally low cholesterol levels. Or how about hypobetalipoproteinemia, which is extremely low levels of LDL - the so-called “bad” cholesterol - and normal or even elevated levels of HDL. It comes with thyroid disorders, liver disease, wasting syndromes, and a greatly elevated risk of cancer.

Bottom line - you need cholesterol, even LDL, or you’re not going to be healthy.

Vegans have LDL in their bodies, too, even with their peculiar avoidance of all animal products.

Production of cholesterol, like production of anything, requires energy. Prior to our current era’s abundance of food, getting sufficient calories was a matter of life or death and people really did starve to death at times. Being able to absorb cholesterol essentially ready-made from the diet meant that instead of expending energy on making cholesterol the body could use that energy for something else - growth, wound healing, making glucose out of fat stores to run the brain until more starch could be found… whatever.

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A quick note - for those not having followed the link - the original article was copied from http://www.vegan-straight-edge.org.uk/taxonomy.htm so the scientific impartiality may be open to question. In fact the bits picked out by **JZesbaugh ** (out of order by the way) are probably most coherent. To pick another paragraph;

It is pretty clear where the author is coming from: “Humans prefer culture and technology over nature, and since our natural role is as a raw food herbivore, and because our bodies are only suited to that role, any significant perversion of it must, and does, lead to ill health.”

Oy!

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All you are doing is Googling terms and linking to any page that contains the words you want to find, without reading and understanding those pages or evaluating the authors.

John Coleman is a raw vegan absolutist. He’s exactly the kind of nutcase you said that you would avoid in your cites.

The rest of your cites have been pulled apart for similar reasons. You haven’t read any of the originals or full articles, and you are making basic mistakes in interpretation.

That’s mainly because you don’t understand the process of digestion. And you don’t understand that how the body uses the results, the simple sugars, amino acids, and fatty acids that are produced starting with any set of starches, proteins, and fats, is a totally different set of processes.

Humans have a large set of intestinal enzymes, with estimates ranging up to 500,000. The digestive process does begin in the mouth, but that doesn’t mean that what is broken down there is any more vital or basic than any other component. Breakdown, which is digestion, takes place in the mouth, stomach, and small intestine. Some molecules need a set of processes before they arrive at their simplest state. That’s because it’s only the simple end products that can be absorbed into the bloodstream through the walls of the small intestine. (There are a few products that cannot be digested, a set of fibers that are easily digested by true herbivores. That’s the most telling evidence that humans are not herbivores, a basic fact you have ignored throughout.)

Digestion stops there. The use of the breakdown products and the rebuilding of those into more complex molecules that the body uses for fuel, repair, and growth is entirely different, no matter how many times you conflate the two. The balance and type of foods you eat will affect how the body can process them later on, just as any factory depends on getting the proper balance and amount of raw materials. But anthropology tells us that the body is incredibly adaptable, and can thrive on almost any diet, from raw vegetables to all meats. Some diets are unhealthy, but these have nothing to do with digestion. The over-abundance of fats, sugars, and proteins that many Americans eat are digested just fine.

You keep arguing from false premises, which is why none of your arguments can be supported. Please take the time to get off the Internet and find some good basic books on human metabolism. And stop citing stuff you haven’t read. It just backfires when somebody who can properly judge it takes a look.

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In this instance though he is absolutely correct. His points oddly echoed my own. And those of the National Geographic Article. I don’t care what he is so long as he has his facts strait.

Essentially a given mammal can eat outside their given biological niche. Humans for example have learned many ways to do this, this does not mean the human set up, as the author identified is primarily a herbivore.

Then in this mad race to prove me wrong, you are all ignoring two pieces of MAJOR evidence.

Chimps diet.  Primarily Herbivore.

Lucy’s diet. Which is posted. Primarily, if not all Herbivore.

Ice mans diet. Primarily Herbivore.

 Biological Similarities to Herbivores.

Where are you getting this OTHER STUFF???

Now there may be two schools of thought on this.

Biological predisposition and Behaviorally acquired.