I think Paul Getty brings up some interesting points, pointing out that
prior to our evolution into hominids eating goodly portions of meat, the
diet of our primate ancestors was primarily (though not exclusively)
vegetarian (actually, from approx. 50 million to at least 10 million years
ago). On the other hand, for many millions of years prior to *that*, their
own ancestors were largely insectivores--from 65 million to 50 million
years ago, so the balance in the diet between foods of animal and plant
origin has switched a couple of times along the evolutionary track that led
to human beings. [Andrews P, Martin L (1992) "Hominoid dietary evolution."
In Whiten A, Widdowson EM (eds) "Foraging Strategies and Natural Diet of
Monkeys, Apes, and Humans." Oxford, Eng.: Clarendon Press., p. 41; also
Foley R (1995) Humans Before Humanity. Cambridge, Mass.: Blackwell Pub.]

Can we have lost all or even *most* of the need for goodly amounts of plant
foods as well? I for one don't think so. Especially with studies showing
the anti-cancer, and anti-oxidant effects of fresh fruits and vegetables.
The prime two questions in my mind are: (a) how "conservative" is
evolution--that is, which "old" adaptations are lost in the face of "newer"
ones, and which are conserved, and why? (b) how quickly can evolution take
place with intense selective pressures? While we have seen the example of
the lizards on the Caribbean island(s) that Todd Moody gave (very exciting
and interesting to read about), and there are the examples of lactose and
gluten tolerance in some portion of the human species, it is probably not
going to be until the field of genetics progresses sufficiently far enough
that we are ever going to know the genetic mechanisms precisely enough to
enable us to evaluate just what degree of adaptation any of this indicates
to recent changes in our diet with more relative certainty.

One thing I have been meaning to bring up for some time here in relation to
the subject of eating high amounts of meat in the diet, almost to the
exclusion of any plant food, is how lionized the Eskimos have been on this
list, yet they have some significant health problems on their 90% meat diet
that no one has pointed out yet, which I find curious. While as Dean Esmay
recently pointed out it's true they don't have the type of health problems
on their 50% or 70% fat diet normally attributed to excessive fat
consumption, there are some other problems they do have. And it seems at
least possible, if not plausible to me, it could be due to the very low
incidence of plant food in their traditional diet. Also, we need to
remember the Arctic was not colonized till even later than the dates for
the agricultural revolution--I am thinking maybe 2000 to 4000 years ago,
but might be a little off here without references in front of me--so the
Inuit and other Eskimos would have had even less time to adapt to some of
the extremes of their diet as lower-latitude dwellers would have had to
adapt to high rates of grain consumption.

1. One study of the Eskimos has showed them to have high rates of
osteoporosis. [See Mazess RB, Mather W (1974) "Bone mineral content of
North Alaskan Eskimos." American Journal of Clinical Nutrition, vol. 27,
no. 9 (Sept. 1974), pp. 916-925.] This is a study I have looked at myself,
and although it has been awhile since I've seen it, I believe this study
was of Eskimos prior to acculturation, eating their traditional diet.

2. Lee Hitchcox, in his book Long Life Now, points out that Eskimos also
"bruise easily, are slow to form blood clots, develop fatal nosebleeds, and
have no heart disease.... The Eskimos have one of the world's highest rates
of hemorrhagic stroke, osteoporosis ["starting at age 40," he mentions
elsewhere in the book p.189)], obesity, and one of the shortest life spans.
They apparently die from other diseases before cancer or heart disease have
a chance to develop." (p.93) However, in info from a 1993 study (which may
not apply to the earlier studies of Eskimos living in purer environments)
Hitchcox also states that "the fat tissues of Inuit mothers contain the
highest known levels of organochlorine pesticides" (without, unfortunately,
giving any help as to how that fact might confound any interpretations of
the dietary evidence). Lee gives as references the one above, as well as
two additional ones: [Ho K (1972) "Alaska Arctic Eskimos: responses to a
customary high-fat diet," American Journal of Clinical Nutrition, vol.25,
p.737.; and secondly, Dewailly E (1993) "Inuit exposure to organochlorines
through the aquatic food chain in Arctic Quebec," Environmental Health
Perspectives, vol.101, p.618] I haven't looked at these two studies myself,
but thought I would post the references. I believe I have another reference
or two from Hitchcox about health problems in the Eskimo I would be happy
to share but can't currently locate them,

(I might mention here that Hitchcox believes in a rather ludicrous 1 or 2%
animal food diet, being otherwise a proponent of high-starch somewhat
McDougall-style diets, basing much of his argument on the circumstantial
evidence of long-lived cultures such as the Hunzakut, while ignoring
mounting evidence as to the dangers of grains for most people. He does,
however, seem to nail his references well, from what I have been able to
tell in tracking down several of the ones he lists in his book. )

Paul writes:

>Isn't it likely that as man evolved the mental capacity and physical
>characteristics to be able to hunt animals that before were elusive to him,
>that his body evolved to not only be able to utilize meat, but also
>retained the ability to utilize all those foods that made up his diet
>before?  Surely he could have just added those enzymes and processes
>necessary to metabolize meat, with losing the ability to live off a plant
>diet.

To some degree, I would be inclined to guess the answer to this yes, but to
some degree no. After all, we still remain omnivores capable of eating a
wide range of foods, and have not become total carnivores. However, on the
other hand, evolution of new capacities always carries some lost
"opportunity cost," because the metabolic energy to support the newly
evolved capacities must come from somewhere. My understanding of current
theories of increasing brain encephalization (increased size relative to
body weight) in the hominid line of evolution, as explained by researcher
Loren Cordain (somewhere in the Paleodiet archives, perhaps) is that the
larger brain would not have been possible without an increasing percentage
of concentrated animal foods in the diet. As the human gut evolved to
subsist on a more concentrated diet with more animal foods, the gut became
smaller since the energy more gut tissue would take was being redirected to
the larger brain. So the gut lost some of its former ability to extract as
much nutrition out of more fibrous, less dense plant matter. At least that
is the theory. In other primates the gut is dominated by the colon which (I
believe, someone tell me if wrong) harboring the fermentative bacteria in
their guts that enables them to break down diets of 90% or more fibrous
plant foods more efficiently. In humans, the gut is dominated by the small
intestine which handles the more concentrated foods like animal meat.

>I don't think there is any question that man had only incompletely evolved
>into a carnivore.  His teeth are not very different from vegitarian apes.
>They have none of the characteristics of carnivores.

True, but what's often forgotten is that technology in the form of stone
tools served to diminish the need for carnivore teeth. I don't have
references right at hand on this, but I know studies have shown that
hominid teeth decreased in size and robustness over the eons as tool use
increased. In adapting to changes in foods, evolution doesn't care HOW they
get into the body, only that they DID--after that, it is simply a matter of
sufficient time and selective pressures whether adaptation takes place or
not. (This same argument would apply to fire/cooking as a technology as
well, by the way, in whether or how much we are, or are not, adapted to it.
One can't rule it out just on the basis it is a technology, because
evolutionary processes don't care about that. Another way of saying this is
that technology is just another part of the environment, and changes in
environment are a key part of the "engine" driving evolutionary change.)
Evolutionary biologists use several characteristics to define the hominid
adaptation, and technology (tool use) is prime among them, along with
increased brain size and intelligence, bipedalism, etc.

>And for all the talk here about the relative size of brain to digestive
>system >length, the length of the intestines of man is more like those of
>vegitarian >primates than those of canines or felines.

Surface area of the intestines, and cell types, are what matter, not
length, in this consideration. In this regard, humans are more like
carnivores and omnivores than vegetarians. See, of all places(!), The Vegan
Handbook (1996), for an article by anatomist John McArdle, "Humans are
omnivores," addressing the flaws in traditional vegetarian arguments based
on comparative anatomy. McArdle points out several misconceptions as to
human digestive anatomy, such as:

1. "The relationship between form (anatomy/physiology) and function
(behavior) is not always one to one. Individual anatomical structures can
serve one or more functions and similar functions can be served by several
different forms."

2. "Cell types: Relative number and distribution of cell types, as well as
structural specializations, are more important than overall length of the
intestine to determining a typical diet. Dogs are typical carnivores, but
their intestinal characteristics have more in common with omnivores.
[perhaps due to domestication?--my question] Wolves eat quite a lot of
plant material."

3. "Fermenting vats: Nearly all plant eaters [in the exclusive sense of the
term, as he indicates elsewhere] have fermenting vats (enlarged chambers
where food 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."

4. "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 suppot 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
archaeological 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 archaeological excavations."

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

6. "Intestine: Intestinal absorption is a surface area, not linear problem.
Dogs (who 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."

(end excerpt)

>He still retained the attraction for sugars and starches. Try feeding an
>apple >to a lion....the lion doesn't think of it as food. But plant foods
>are >attractive to man. The first enzymes to work on our food is amylase
>to start >carbohydrate breakdown in the mouth. Certainly this enzyme
>didn't come about >in man in the last 20,000 years.

I agree. I think sometimes on this list we can be just a tad (actually much
more than a tad!) overzealous about the virtues of subsisting on nothing
but pemmican and so forth. How many times has it been repeated here that
studies of modern hunter-gatherers average around 50-60% animal food in
their diets (that's not the whole diet, it's about half the diet), and then
we jump to the extreme of making paeans to the Eskimo eating 90% or more.
Or to explorers and backwoodsmen in pre and post-revolutionary America who
were FORCED to live on mostly animal flesh during the wintry season without
a choice in the matter. Don't think they weren't craving some wild berries
as soon as they could get their hands on some! :-)

>In short, I feel man is the product of quick changes in environment in the
>past million years and has retained the ability to be herbivore or
>carnivore but is best being somewhere in between these extremes.  In fact
>it seems we retain a requirement for a lot of fiber, and if we don't get it
>there are definitely health consequences.  We don't get enough, and without
>supplemental fiber a diet high in modern animal protein is almost surely
>low in fiber.  Supplemental fiber, with all other things staying the same,
>lowers cholesterol, lowers triglycerides, lowers LDL, raises HDL, decreases
>colo-rectal cancer, decreases breast cancer, decreases pancreatic cancer,
>and helps in constipation and loose bowels and irritable bowel sydrome.
>Clearly we don't get enough fiber in our diets.  Our digestive system, on
>it's way to evolving ways to utilize more meat, did not lose it's need for
>plant foods.

Good points all, and all too easy to forget if we become as overzealous as
vegetarians do, but in the opposite direction.

--Ward Nicholson <[log in to unmask]> Wichita, KS