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artbeat
Oct 8th, 2004, 08:11 PM
http://www.ecologos.org/anatomy.htm


To: psychoceramics@zikzak.net
Subject: psychoceramics: The Comparative Anatomy of Eating
From: Ernie Karhu <ekarhu @ suneast.East.Sun.COM>
Date: Tue, 26 Mar 1996 08:38:09 -0500
Sender: owner-psychoceramics

NOTE: this author uses the term "herbivore" in the most general sense of eating only plant material, and, unfortunately, does NOT differentiate between the more-restrictive, more common, application of the word "herbivore" to refer to grazing animals only; e.g. cattle, sheep, goats, etc., which have quite special, unique adaptations necessary to eat and properly digest only grasses and leaves, and are therefore quite different in digestive physiology than the frugivorous (eats primarily fruit) apes, in which classification the human species really belongs.[LF]




The Comparative Anatomy of Eating

by Milton R. Mills, M.D.




Humans are most often described as "omnivores". This classification is based on the "observation" that humans generally eat a wide variety of plant and animal foods. However, culture, custom and training are confounding variables when looking at human dietary practices. Thus, "observation" is not the best technique to use when trying to identify the most "natural" diet for humans. While most humans are clearly "behavioral" omnivores, the question still remains as to whether humans are anatomically suited for a diet that includes animal as well as plant foods.

A better and more objective technique is to look at human anatomy and physiology. Mammals are anatomically and physiologically adapted to procure and consume particular kinds of diets. (It is common practice when examining fossils of extinct mammals to examine anatomical features to deduce the animal's probable diet.) Therefore, we can look at mammalian carnivores, herbivores (plant-eaters) and omnivores to see which anatomical and physiological features are associated with each kind of diet. Then we can look at human anatomy and physiology to see in which group we belong.

Oral Cavity

Carnivores have a wide mouth opening in relation to their head size. This confers obvious advantages in developing the forces used in seizing, killing and dismembering prey. Facial musculature is reduced since these muscles would hinder a wide gape, and play no part in the animal's preparation of food for swallowing. In all mammalian carnivores, the jaw joint is a simple hinge joint lying in the same plane as the teeth. This type of joint is extremely stable and acts as the pivot point for the "lever arms" formed by the upper and lower jaws. The primary muscle used for operating the jaw in carnivores is the temporalis muscle. This muscle is so massive in carnivores that it accounts for most of the bulk of the sides of the head (when you pet a dog, you are petting its temporalis muscles). The "angle" of the mandible (lower jaw) in carnivores is small. This is because the muscles (masseter and pterygoids) that attach there are of minor importance in these animals. The lower jaw of carnivores cannot move forward, and has very limited side-to-side motion. When the jaw of a carnivore closes, the blade-shaped cheek molars slide past each other to give a slicing motion that is very effective for shearing meat off bone.

The teeth of a carnivore are discretely spaced so as not to trap stringy debris. The incisors are short, pointed and prong-like and are used for grasping and shredding. The canines are greatly elongated and dagger-like for stabbing, tearing and killing prey. The molars (carnassials) are flattened and triangular with jagged edges such that they function like serrated-edged blades. Because of the hinge-type joint, when a carnivore closes its jaw, the cheek teeth come together in a back-to-front fashion giving a smooth cutting motion like the blades on a pair of shears.

The saliva of carnivorous animals does not contain digestive enzymes. When eating, a mammalian carnivore gorges itself rapidly and does not chew its food. Since proteolytic (protein-digesting) enzymes cannot be liberated in the mouth due to the danger of autodigestion (damaging the oral cavity), carnivores do not need to mix their food with saliva; they simply bite off huge chunks of meat and swallow them whole.

According to evolutionary theory, the anatomical features consistent with an herbivorous diet represent a more recently derived condition than that of the carnivore. Herbivorous mammals have well-developed facial musculature, fleshy lips, a relatively small opening into the oral cavity and a thickened, muscular tongue. The lips aid in the movement of food into the mouth and, along with the facial (cheek) musculature and tongue, assist in the chewing of food. In herbivores, the jaw joint has moved to position above the plane of the teeth. Although this type of joint is less stable than the hinge-type joint of the carnivore, it is much more mobile and allows the complex jaw motions needed when chewing plant foods. Additionally, this type of jaw joint allows the upper and lower cheek teeth to come together along the length of the jaw more or less at once when the mouth is closed in order to form grinding platforms. (This type of joint is so important to a plant-eating animal, that it is believed to have evolved at least 15 different times in various plant-eating mammalian species.) The angle of the mandible has expanded to provide a broad area of attachment for the well-developed masseter and pterygoid muscles (these are the major muscles of chewing in plant-eating animals). The temporalis muscle is small and of minor importance. The masseter and pterygoid muscles hold the mandible in a sling-like arrangement and swing the jaw from side-to-side. Accordingly, the lower jaw of plant-eating mammals has a pronounced sideways motion when eating. This lateral movement is necessary for the grinding motion of chewing.

The dentition of herbivores is quite varied depending on the kind of vegetation a particular species is adapted to eat. Although these animals differ in the types and numbers of teeth they posses, the various kinds of teeth when present, share common structural features. The incisors are broad, flattened and spade-like. Canines may be small as in horses, prominent as in hippos, pigs and some primates (these are thought to be used for defense) or absent altogether. The molars, in general, are squared and flattened on top to provide a grinding surface. The molars cannot vertically slide past one another in a shearing/slicing motion, but they do horizontally slide across one another to crush and grind. The surface features of the molars vary depending on the type of plant material the animal eats. The teeth of herbivorous animals are closely grouped so that the incisors form an efficient cropping/biting mechanism, and the upper and lower molars form extended platforms for crushing and grinding. The "walled-in" oral cavity has a lot of potential space that is realized during eating.

These animals carefully and methodically chew their food, pushing the food back and forth into the grinding teeth with the tongue and cheek muscles. This thorough process is necessary to mechanically disrupt plant cell walls in order to release the digestible intracellular contents and ensure thorough mixing of this material with their saliva. This is important because the saliva of plant-eating mammals often contains carbohydrate-digesting enzymes which begin breaking down food molecules while the food is still in the mouth.

Stomach and Small Intestine

Striking differences between carnivores and herbivores are seen in these organs. Carnivores have a capacious simple (single-chambered) stomach. The stomach volume of a carnivore represents 60-70% of the total capacity of the digestive system. Because meat is relatively easily digested, their small intestines (where absorption of food molecules takes place) are short -- about three to five or six times the body length. Since these animals average a kill only about once a week, a large stomach volume is advantageous because it allows the animals to quickly gorge themselves when eating, taking in as much meat as possible at one time which can then be digested later while resting. Additionally, the ability of the carnivore stomach to secrete hydrochloric acid is exceptional. Carnivores are able to keep their gastric pH down around 1-2 even with food present. This is necessary to facilitate protein breakdown and to kill the abundant dangerous bacteria often found in decaying flesh foods.

Because of the relative difficulty with which various kinds of plant foods are broken down (due to large amounts of indigestible fibers), herbivores have significantly longer and in some cases, far more elaborate guts than carnivores. Herbivorous animals that consume plants containing a high proportion of cellulose must "ferment" (digest by bacterial enzyme action) their food to obtain the nutrient value. They are classified as either "ruminants" (foregut fermenters) or hindgut fermenters. The ruminants are the plant-eating animals with the celebrated multiple-chambered stomachs. Herbivorous animals that eat a diet of relatively soft vegetation do not need a multiple-chambered stomach. They typically have a simple stomach, and a long small intestine. These animals ferment the difficult-to-digest fibrous portions of their diets in their hindguts (colons). Many of these herbivores increase the sophistication and efficiency of their GI tracts by including carbohydrate-digesting enzymes in their saliva. A multiple-stomach fermentation process in an animal which consumed a diet of soft, pulpy vegetation would be energetically wasteful. Nutrients and calories would be consumed by the fermenting bacteria and protozoa before reaching the small intestine for absorption. The small intestine of plant-eating animals tends to be very long (greater than 10 times body length) to allow adequate time and space for absorption of the nutrients.

Colon

The large intestine (colon) of carnivores is simple and very short, as its only purposes are to absorb salt and water. It is approximately the same diameter as the small intestine and, consequently, has a limited capacity to function as a reservoir. The colon is short and non-pouched. The muscle is distributed throughout the wall, giving the colon a smooth cylindrical appearance. Although a bacterial population is present in the colon of carnivores, its activities are essentially putrefactive.

In herbivorous animals, the large intestine tends to be a highly specialized organ involved in water and electrolyte absorption, vitamin production and absorption, and/or fermentation of fibrous plant materials. The colons of herbivores are usually wider than their small intestine and are relatively long. In some plant-eating mammals, the colon has a pouched appearance due to the arrangement of the muscle fibers in the intestinal wall. Additionally, in some herbivores the cecum (the first section of the colon) is quite large and serves as the primary or accessory fermentation site.

What About Omnivores?

One would expect an omnivore to show anatomical features which equip it to eat both animal and plant foods. According to evolutionary theory, carnivore gut structure is more primitive than herbivorous adaptations. Thus, an omnivore might be expected to be a carnivore which shows some gastrointestinal tract adaptations to an herbivorous diet.

This is exactly the situation we find in the Bear, Raccoon and certain members of the Canine families. (This discussion will be limited to bears because they are, in general, representative of the anatomical omnivores.) Bears are classified as carnivores but are classic anatomical omnivores. Although they eat some animal foods, bears are primarily herbivorous with 70-80% of their diet comprised of plant foods. (The one exception is the Polar bear which lives in the frozen, vegetation poor arctic and feeds primarily on seal blubber.) Bears cannot digest fibrous vegetation well, and therefore, are highly selective feeders. Their diet is dominated by primarily succulent lent herbage, tubers and berries. Many scientists believe the reason bears hibernate is because their chief food (succulent vegetation) not available in the cold northern winters. (Interestingly, Polar bears hibernate during the summer months when seals are unavailable.)

In general, bears exhibit anatomical features consistent with a carnivorous diet. The jaw joint of bears is in the same plane as the molar teeth. The temporalis muscle is massive, and the angle of the mandible is small corresponding to the limited role the pterygoid and masseter muscles play in operating the jaw. The small intestine is short ( less than five times body length) like that of the pure carnivores, and the colon is simple, smooth and short. The most prominent adaptation to an herbivorous diet in bears (and other "anatomical" omnivores) is the modification of their dentition. Bears retain the peg-like incisors, large canines and shearing premolars of a carnivore; but the molars have become squared with rounded cusps for crushing and grinding. Bears have not, however, adopted the flattened, blunt nails seen in most herbivores and retain the elongated, pointed claws of a carnivore.

An animal which captures, kills and eats prey must have the physical equipment which makes predation practical and efficient. Since bears include significant amounts of meat in their diet, they must retain the anatomical features that permit them to capture and kill prey animals. Hence, bears have a jaw structure, musculature and dentition which enable them to develop and apply the forces necessary to kill and dismember prey even though the majority of their diet is comprised of plant foods. Although an herbivore-style jaw joint (above the plane of the teeth) is a far more efficient joint for crushing and grinding vegetation and would potentially allow bears to exploit a wider range of plant foods in their diet, it is a much weaker joint than the hinge-style carnivore joint. The herbivore-style jaw joint is relatively easily dislocated and would not hold up well under the stresses of subduing struggling prey and/or crushing bones (nor would it allow the wide gape carnivores need). In the wild, an animal with a dislocated jaw would either soon starve to death or be eaten by something else and would, therefore, be selected against. A given species cannot adopt the weaker but more mobile and efficient herbivore-style joint until it has committed to an essentially plant-food diet test it risk jaw dislocation, death and ultimately, extinction.

What About Me?

The human gastrointestinal tract features the anatomical modifications consistent with an herbivorous diet. Humans have muscular lips and a small opening into the oral cavity. Many of the so-called "muscles of expression" are actually the muscles used in chewing. The muscular and agile tongue essential for eating, has adapted to use in speech and other things. The mandibular joint is flattened by a cartilaginous plate and is located well above the plane of the teeth. The temporalis muscle is reduced. The characteristic "square jaw" of adult males reflects the expanded angular process of the mandible and the enlarged masseter/pterygoid muscle group. The human mandible can move forward to engage the incisors, and side-to-side to crush and grind.

Human teeth are also similar to those found in other herbivores with the exception of the canines (the canines of some of the apes are elongated and are thought to be used for display and/or defense). Our teeth are rather large and usually abut against one another. The incisors are flat and spade-like, useful for peeling, snipping and biting relatively soft materials. The canines are neither serrated nor conical, but are flattened, blunt and small and function Like incisors. The premolars and molars are squarish, flattened and nodular, and used for crushing, grinding and pulping noncoarse foods.

Human saliva contains the carbohydrate-digesting enzyme, salivary amylase. This enzyme is responsible for the majority of starch digestion. The esophagus is narrow and suited to small, soft balls of thoroughly chewed food. Eating quickly, attempting to swallow a large amount of food or swallowing fibrous and/or poorly chewed food (meat is the most frequent culprit) often results in choking in humans.

Man's stomach is single-chambered, but only moderately acidic. (Clinically, a person presenting with a gastric pH less than 4-5 when there is food in the stomach is cause for concern.) The stomach volume represents about 21-27% of the total volume of the human GI tract. The stomach serves as a mixing and storage chamber, mixing and liquefying ingested foodstuffs and regulating their entry into the small intestine. The human small intestine is long, averaging from 10 to 11 times the body length. (Our small intestine averages 22 to 30 feet in length. Human body size is measured from the top of the head to end of the spine and averages between two to three feet in length in normal-sized individuals.)

The human colon demonstrates the pouched structure peculiar to herbivores. The distensible large intestine is larger in cross-section than the small intestine, and is relatively long. Man's colon is responsible for water and electrolyte absorption and vitamin production and absorption. There is also extensive bacterial fermentation of fibrous plant materials, with the production and absorption of significant amounts of food energy (volatile short-chain fatty acids) depending upon the fiber content of the diet. The extent to which the fermentation and absorption of metabolites takes place in the human colon has only recently begun to be investigated.

In conclusion, we see that human beings have the gastrointestinal tract structure of a "committed" herbivore. Humankind does not show the mixed structural features one expects and finds in anatomical omnivores such as bears and raccoons. Thus, from comparing the gastrointestinal tract of humans to that of carnivores, herbivores and omnivores we must conclude that humankind's GI tract is designed for a purely plant-food diet.

Summary

Facial Muscles

CARNIVORE: Reduced to allow wide mouth gape
HERBIVORE: Well-developed
OMNIVORE: Reduced
HUMAN: Well-developed

Jaw Type

CARNIVORE: Angle not expanded
HERBIVORE: Expanded angle
OMNIVORE: Angle not expanded
HUMAN: Expanded angle

Jaw Joint Location

CARNIVORE: On same plane as molar teeth
HERBIVORE: Above the plane of the molars
OMNIVORE: On same plane as molar teeth
HUMAN: Above the plane of the molars

Jaw Motion

CARNIVORE: Shearing; minimal side-to-side motion
HERBIVORE: No shear; good side-to-side, front-to-back
OMNIVORE: Shearing; minimal side-to-side
HUMAN: No shear; good side-to-side, front-to-back

Major Jaw Muscles

CARNIVORE: Temporalis
HERBIVORE: Masseter and pterygoids
OMNIVORE: Temporalis
HUMAN: Masseter and pterygoids

Mouth Opening vs. Head Size

CARNIVORE: Large HERBIVORE: Small OMNIVORE: Large HUMAN:
Small

Teeth: Incisors

CARNIVORE: Short and pointed
HERBIVORE: Broad, flattened and spade shaped
OMNIVORE: Short and pointed
HUMAN: Broad, flattened and spade shaped

Teeth: Canines

CARNIVORE: Long, sharp and curved
HERBIVORE: Dull and short or long (for defense), or none
OMNIVORE: Long, sharp and curved
HUMAN: Short and blunted

Teeth: Molars

CARNIVORE: Sharp, jagged and blade shaped
HERBIVORE: Flattened with cusps vs complex surface
OMNIVORE: Sharp blades and/or flattened
HUMAN: Flattened with nodular cusps

Chewing

CARNIVORE: None; swallows food whole
HERBIVORE: Extensive chewing necessary
OMNIVORE: Swallows food whole and/or simple crushing
HUMAN: Extensive chewing necessary

Saliva

CARNIVORE: No digestive enzymes
HERBIVORE: Carbohydrate digesting enzymes
OMNIVORE: No digestive enzymes
HUMAN: Carbohydrate digesting enzymes

Stomach Type

CARNIVORE: Simple
HERBIVORE: Simple or multiple chambers
OMNIVORE: Simple
HUMAN: Simple

Stomach Acidity

CARNIVORE: Less than or equal to pH 1 with food in stomach
HERBIVORE: pH 4 to 5 with food in stomach
OMNIVORE: Less than or equal to pH 1 with food in stomach
HUMAN: pH 4 to 5 with food in stomach

Stomach Capacity

CARNIVORE: 60% to 70% of total volume of digestive tract
HERBIVORE: Less than 30% of total volume of digestive tract
OMNIVORE: 60% to 70% of total volume of digestive tract
HUMAN: 21% to 27% of total volume of digestive tract

Length of Small Intestine

CARNIVORE: 3 to 6 times body length
HERBIVORE: 10 to more than 12 times body length
OMNIVORE: 4 to 6 times body length
HUMAN: 10 to 11 times body length

Colon

CARNIVORE: Simple, short and smooth
HERBIVORE: Long, complex; may be sacculated
OMNIVORE: Simple, short and smooth
HUMAN: Long, sacculated

Liver

CARNIVORE: Can detoxify vitamin A
HERBIVORE: Cannot detoxify vitamin A
OMNIVORE: Can detoxify vitamin A
HUMAN: Cannot detoxify vitamin A

Kidney

CARNIVORE: Extremely concentrated urine
HERBIVORE: Moderately concentrated urine
OMNIVORE: Extremely concentrated urine
HUMAN: Moderately concentrated urine

Nails

CARNIVORE: Sharp claws
HERBIVORE: Flattened nails or blunt hooves
OMNIVORE: Sharp claws
HUMAN: Flattened nails

my3labs
Jul 14th, 2005, 08:29 AM
I read something similar to this recently. VERY good information. I've been using this with my mom who is on the verge of at least becoming a vegetarian.

FR
Jul 14th, 2005, 11:15 AM
I agree with this article. I once was arguing with someone (a vegetarian at that) who had some sort of degree in biology and did not agree with this assessment. I was thinking to myself, what a waste of money on an education and subsequent degree if you cannot clearly agree to this. Someone then brought up, but carnivores and omnivores do not have eyes on the side of their head, that they are focused in a straight manner. I again thought to myself, haven't these people ever seen a snake before? Although a human may not match every single possible characteristic of a typical herbivore, we share damn near every characteristic with an herbivore (as shown by the referenced article) whereas we share almost none with an omnivore, or carnivore. Humans are nothing more than behavioral omnivores as stated in that article. I almost fall out laughing when a person says that we have omnivorous canine teeth. Oh really? Our teeth resemble that of a dog? Dogs are omnivores and our teeth are nothing like theirs. In fact, the only animals humans could possibly dig into and chew raw are insects, just like any other herbivore could. Humans may have not had enough intelligence during our early stages of development to realize we are natural herbivores, and thus survived on plants, insects, and animal scraps left behind by true omnivores and carnivores.

harpy
Jul 14th, 2005, 12:43 PM
A contrasting (but still pro-vegetarian) viewpoint here:

http://www.vrg.org/nutshell/omni.htm

To me, it doesn't really make any difference whether humans are naturally omnivorous or vegan. The important point is that we can be healthy as vegans.

Mozbee
Jul 14th, 2005, 03:33 PM
I just love the summary!

AbFab
Aug 11th, 2005, 06:05 PM
To me, it doesn't really make any difference whether humans are naturally omnivorous or vegan. The important point is that we can be healthy as vegans.I agree. Not just healthy, but THE healthiest! (if it's done right). But I love these herbivore-carnivore-omnivore-human facts so we can show those who harp on about it being natural to eat meat, like WE are the abnormal ones, that actually, no, it's not, not for us humans. All the evidence for me points to veganism being THE most obviously natural way to be. I do accept, that when your food choices are severly limited, meat can be the only way to survive, but for the majority of us, we have a choice. Thank goodness for that.

Kiran
Aug 12th, 2005, 01:53 AM
Talking about mouth movement.. something worth noticing!! Consider herbivores animals like cows, Horses, deer, donkeys etc. Have you observed how these drink water?? They never put their tounge outside. They are capable of drinking water just using their mouth movement and don't need additional assistance from their tounge.

On the other hand, consider carnivores like Lions, tigers, hyenas, dogs and cats. These drink fluids using a recursive tounge movement. They put their tounges outside lick the water, and the tounge goes in. The process is repeated and tounge goes in and out till the animal feels sufficient.

Hence meat eating humans belonging to that category. They are to be classified that way. It is upto to each indivigual to decide if he wants to be a herbivore or a carnivore. Personally, I cannot imagine me drinking like carnivores. It seems disgusting for humans. I am hence proud to be a vegan.

Mozbee
Aug 12th, 2005, 03:11 PM
I suppose it depends aswell, how desparate the animals hunger is for mouth lubricant!

Korn
Aug 18th, 2005, 12:16 PM
From http://www.veganbodybuilding.com/phpBB2/viewtopic.php?t=514 :

http://img.photobucket.com/albums/v291/kristopher570/meanttoconsume.jpg

griggsy
Feb 7th, 2006, 12:08 PM
I have only been veg*n a couple of months now, and one of the debates that i find really interesting is whether or not humans are designed to eat meat.
It seems to me that there is a lot of evidence that the human body was designed to digest plants, not meat, and that anatomically we're more like herbivores than carnivores. However I know that a lot of veg*ns disagree with this opinion.
I'd be really interested to hear others opinions on this matter.

I found a really interesting table online at http://michaelbluejay.com/veg/natural.html

Korn
Feb 7th, 2006, 12:35 PM
Hi Griggsy, I just merged your thread with a similar, existing thread.
We also have this thread:
Did humans always eat meat? (http://www.veganforum.com/forums/showthread.php?t=1194)

rantipole
Feb 7th, 2006, 03:56 PM
I think we evolved from primarily herbivorous primates. However, from the reading I've done on human evolution, it seems our early ancestors (Australopithicines and such) were herbivores that would eat meat opportunistically. In other words, we'd eat meat when available but really didn't go after it as such. As much as some people want to picture man as a mighty hunter, we mostly got meat we scavenged or could easily overpower (grab that lizard!). So, humans and our early ancestors almost unquestionably ate meat, but it probably amounted to less than 5 percent of the total diet.

Cheers,
rant

Pilaf
Feb 7th, 2006, 05:17 PM
I'd like to point something else out, here...

Modren day omni doctors, scientists and historians arrogantly claim that "without the protein found in meat, our early ancestors' brains would not have developed to the points they are today."

Such comments reveal their damning arrogance and ignorance.. the protein is what caused the brains the develop, NOT the meat itself. Protein can be derived quite easily from plant sources. So maybe their vaunted wisdom is a little outdated. Maybe it was only the protein, which we happened to get from meat (or maybe not). Scientists and doctors always ignore the obvious - that nutrients contribute more to health and evolution than some of the foods they're derived from. It's much the same as the argument that dairy is essential because it's full of calcium...when most vegans learn that calcium is easily found in many plant sources, but they say "the calcium in dairy makes strong bones and teeth!" (yeah right)

Tigerlily
Feb 7th, 2006, 05:19 PM
Whether humans are designed to eat meat or not, it does not justify the cruel, unnecessary conditions we treat animals!

:)

Tiggerwoo
Feb 7th, 2006, 05:42 PM
Whether humans are designed to eat meat or not, it does not justify the cruel, unnecessary conditions we treat animals!

:)

Couldn't agree more Tigerlily. Very apt! :)

Seaside
Feb 7th, 2006, 07:27 PM
What I often remember when one of the cats is licking my nose (ow!) is that contrary to popular belief, cats do not have hairy tongues for grooming purposes. Those scratchy hairs are for cleaning the meat off the bones of their kills. If humans were natural carnivores they would have hairy tongues too, and not just sharp teeth! :eek:

PinkLogik
Feb 8th, 2006, 01:02 PM
If it's not necessary to eat meat (which us vegans prove on a daily basis by merely existing, albeit mostly healthfully) then it's unnecessary to subscribe to animal suffering.

That table was interesting Korn, never seen that before. But it confirmed what I already believed and have read about before. We are not physiologically designed to digest animal proteins, at least in the quantities that most people today consume. It's no wonder there is alot of illness - that and food additives (chemicals), salt and sugar....

Korn
Jul 9th, 2006, 12:06 AM
http://www.goveg.com/images/quote-nhd.gif


The Natural Human Diet (http://www.goveg.com/naturalhumandiet.asp)

Physical characteristics are our best evidence as to what we are meant to eat. (http://groups.msn.com/CrazyVegan/humanherbivore.msnw)


The Comparative Anatomy of Eating (http://www.vegsource.com/veg_faq/comparative.htm)

Meat and Your Health (http://freethought.homestead.com/Health.html)


...and finally a copy of a quote from this (http://www.ul.ie/~sextonb/eatmeat.htm) site:


In 1990, William Clifford Roberts, the distinguished editor in chief of The American Journal of Cardiology, wrote:

Although human beings eat meat we are not natural carnivores. We were intended to eat plants, fruits and starches! No matter how much fat carnivores eat, they do not develop atheroschlerosis. It's virtually impossible, for example, to produce atheroschlerosis in the dog even when 100 grams of cholesterol are added to its meat ration. (This amount of cholesterol is approximately 200 times the average amount that human beings in the USA eat each day!) In contrast, herbivores rapidly develop atheroschlerosis if they are fed foods, namely fat and cholesterol, intended for carnivores...

Thus, although we think we are one and we act as if we are one, human beings are not natural carnivores. When we kill animals to eat them, they end up killing us because their flesh, which contains cholesterol and saturated fat, was never intended for human beings, who are natural herbivores.

GoatBoy
Jul 13th, 2006, 02:48 AM
thsi is the stuff i keep on saying

Where are the natural killing tools on our body?
Why do we need it cooked to stop it from being poisonous?
Why does it sit in our stomach longer than other foods?
Why is it high in cholestrol?
Why don't we have teeth like canines, felines and other carnivourous animals?
I mean, how many meat eating primates are there? (not many, we are close to apes and they just eat fruit and grass)

of course I only say this when people tell me I'M unnatural, I don't like being a preachy vegan, it does more harm than good.

Risker
Jul 13th, 2006, 04:22 AM
Why do we need it cooked to stop it from being poisonous?


I don't think that's true, I could be wrong, but I think it's only because it's not eaten 'fresh' that it needs to be cooked.

marika5
Aug 13th, 2006, 04:17 AM
Where are the natural killing tools on our body?


The brain, of course!

[snipped questions]


of course I only say this when people tell me I'M unnatural, I don't like being a preachy vegan, it does more harm than good.

Well, I think the truth is that we did evolve to eat more meat than our more markedly herbivorous primate ancestors. You can go back 15 million years to find a strongly frugivorous, herbivorous line. And now our closest relatives get 87-99% of their calories plants.

But somewhere along the line we diverged. Our small intestines are longer and our colons shorter than those of our relatives who are designed to eat considerably more fiber. Also the total length of the GI tract is smaller in the human than in the apes. Nobody is sure when this change took place but some estimate it had to be prior to 160000 years ago. A short part (around 9%) of the last 15 million years.

Although our guts changed, our digestive kinetics seem to have remained the same compared to our closest relatives. So although we are different, we are also still similar in this important way, which is very different from that of a carnivore.

In the human, for some reason, energy needs increased while energy density also increased. This is different from the chimp (who eats mostly fruit and has a small body and a well-developed brain) and the gorilla (who eats mostly leaves and has a huge body and a not-as-well-developed brain but spends much more time eating than the chimp).

Up to some percentage, animal foods are tolerated by the primate body. In the pre-human, more reliance on animal source foods for certain amino and fatty acids allowed for less reliance on plant foods for those particular dietary requirements. They also might have been important for child development, because on a very high fiber diet it may be difficult for children to take in enough energy and satisfy all their requirements.

At least, that is what Katherine Milton says.

It seems clear to me that we did adapt to lower fiber foods and this was well before agriculture so animal foods would have had to have played an important role.

But the most important thing nowadays seems to me that we have the brains and the knowledge to make better choices. We are so lucky that we have these choices!

Another thing to consider is that the first 90% of our last 15 million years is probably more relevant to a lifetime of freedom from disease than the last 10%, and I say this because

1.the most longevous populations seem to be have more strongly plant-based than animal based diets

2.There does seem to be a trend of greater disease rates with lower fiber and higher animal food in the diet.

3. Eskimos are not longevity champs, in fact the only sources I can find shows that pre-1950s, lifespans exceeding 40 years were rare. Nowadays they might make it to 60.

Evolution selects for reproductive success and not freedom from disease for 80-100 years (or more). We can surely make it to 20 on a diet comprised mostly of animals foods. But we may be more likely to make it to 80-100 without cancer, diabetes, heart disease, etc. on a well planned diet comprised solely of plant foods provided we take supplements for B12 and possibly D2.

That's my position and I'm sticking to it.

aidan
Sep 5th, 2006, 04:17 AM
I agree with the ad... we WERE meant to eat meat. But not now - we have become independant and intellectual and KNOW that it is wrong to eat animal products. So the main catchcry 'Meat... we WERE meant to eat it' really is promoting veganism. :)

aubergine
Sep 5th, 2006, 11:55 AM
Our biology is that of a plant eater though...

Oliver Oil
Nov 18th, 2006, 12:27 AM
Extract from their "omnivore" page:

"Humans are often mistaken for omnivores, however they are naturally herbivores whom have become accustomed to the eating of meat for convenience of lifestyle. The fact that humans have been eating meat for the past several thousand years has led to some evolutionary changes in humans geneticism which favours the consumption of meat. Thus causing them to be developing into an omnivorous species. Given several thousand more years with current human diets, the transformation may have successfully occurred genetically, and humans would fit fully into the classification "omnivore".[citation needed]"

Sorry if this is old news. It just gave me a warm glow inside when I read it. Maybe an all-vegan world is possible after all - through enforced genetic re-engineering? :p

Korn
Nov 18th, 2006, 09:59 AM
"The fact that humans have been eating meat for the past several thousand years has led to some evolutionary changes in humans geneticism which favours the consumption of meat." It's a fact that many humans have been eating meat for several thousands of years, but it's also a fact that many humans have not (eg. for religious reasons), which make such a statement misleading IMO...


Thus causing them to be developing into an omnivorous species. I disagree in that too. Even if humans would have been 'accustomed to the eating of meat' (which I also disagree in: lots of diseases are associated with eating meat), that would mean that humans would have been 'omnivores' pr. definition... even if a human can eat something, it doesn't mean that he needs to or are 'designed to' eat it.


Maybe an all-vegan world is possible after all - through enforced genetic re-engineering? :p A vegan world is possible if humans want a vegan world, there's no need for any genetic/physical/biological changes at all... ;)