In an attempt not to be so self-assured and intimidating (thanks, Martha!),
I thought I would bring up something I have not mentioned in regard to
evolution which is very interesting and may also go some ways towards
explaining the caloric restriction studies which is Douglas's interest.
Something I have been considering lately is that while over the long-term,
evolution optimizes the adaptation of a species to the mix of *overall*
selection pressures it has to cope with, because the adaptation is to a
*mix* of pressures, what you get in response is a "best-fit compromise"
adaptation to that mix. In other words, evolution adapts to the real-world
mix of factors (some of which may be at cross-purposes), so if you look at
any one selection pressure, the level of adaptation may not be ideal just
considering that one particular factor. But it will be ideal considering
the mix of pressures that must be adapted to as a whole.
There could be ways to exploit this. For instance, caloric restriction will
increase longevity, but it obviously decreases muscularity which would have
been very important to survival in prehistoric times, but not so much now.
So if one is willing to sacrifice muscularity (which is also probably
easier to achieve with animal foods if bodybuilders are any indication,
even though there are of course *some* vegetarian bodybuilders), you can
get the compensation of increased longevity.
Of course, there may be any number of other effects too. For instance, when
I started eating meat again after 18 years as a vegetarian, among other
things my moods improved which subjectively felt like it was because of
somewhat increased hormone levels. Anyway, this is just to point out maybe
all of this depends on one's objectives. I would personally not find
caloric restriction livable (I have lived on fewer calories during an
earlier attempt at a raw-food diet and felt none too whippy) and so would
be willing to take a somewhat shorter life in exchange for--for me--a
happier life, if it came to that. However, someone like Bob or Douglas
might fare mentally much better on caloric restriction without animal
foods, and if so, more power to them.
My own philosophy about animal foods given modern conditions is to eat only
the amount compatible with the most robust health, because of cost factors
(it ain't cheap!) as well as the fact pesticides are concentrated more the
higher up the food chain you go. However, I still have intentions of
experimenting with a lot more meat than I eat now, which is not all that
much, because I want to first see how I feel over a range of consumption
levels. I am also eating mostly fish, and intend to try more red meat to
see how that goes. Then I will decide later what amount is the "least
optimum" for me all things considered.
Given modern research Doug has mentioned about the possibly life-shortening
effect of too much animal protein, it's another reason why the least amount
of animal protein consistent with good health might be prudent if you are
interested solely in longevity. On the other hand, I think this idea can be
taken too far, because it seems from evolution and even modern research
that some minimal amount of animal foods would be advisable--especially if
one is into caloric restriction given the danger to be guarded against is
deficiency.
Given that nutrients like iron, vitamin D, zinc, etc., are more
bio-available in meat. (Better absorbed.) Also there are nutrients like EPA
which for all practical purposes is not available in plant foods in
appreciable amounts, unless you go to great lengths like making flaxseed
preparations and so forth, but that still may not be enough. And there is
the standard argument that veggies like to make that natural plant foods
contain "nutrients known and yet to be discovered" which is a good reason
to eat them--and which can also be applied to meat for the same reasons.
Okay, now here is some data I found recently on longevity in paleolithic
times that bears on Douglas's ideas/research about the longevity-shortening
effect of meat or protein in the diet. On the surface of it, this data
appears to rebut that idea, but actually, I am present the data just to
show that meat protein does not *necessarily* mean decreased longevity,
because there may be other factors that complicate the equation which can
be inferred from the chart below.
[Source: Angel, Lawrence J. (1984) "Health as a crucial factor in the
changes from hunting to developed farming in the eastern mediterranean."
In: Paleopathology at the Origins of Agriculture. (proceedings of a
conference held in 1982) Orlando: Academic Press. pp.51-73]
These longevity figures are for skeletons where the age at death was
determined using standard "paleopathological" techniques, for prehistoric
humans who lived in the Eastern Mediterranean ("fertile crescent" I would
imagine, but I would have to check more closely) where a lot of research
has been done and the data is available. Main thing to note here about the
short average lifespans compared to modern times is that the major causes
are thought to have been "occupational hazards," i.e., accidents, trauma,
etc., stresses of nomadism, and so forth.
Median Lifespan (yrs)
MALE FEMALE
- 30,000 to 9,000 B.C. 35.4 30.0
("Paleolithic" times, i.e., 65/35 plant/animal diet)
- 9,000 to 7,000 B.C. 33.5 31.3
("Mesolithic" transition period from Paleolithic
to some agricultural products--as diet becomes
more agricultural, it also becomes more
vegetarian in character--as much as 90/10 plant
animal later on according to the Eaton research team)
- 7,000 to 5,000 B.C. 33.6 29.8
("Early Neolithic," i.e., agriculture first spreads
widely)
- 5,000 to 3,000 B.C. 33.1 29.2
("Late Neolithic," i.e., the transition is mostly complete
- 3,000 to 2,000 B.C. ("Early Bronze" period) 33.6 29.4
- 2,000 to 1,450 B.C. ("Middle People/Bronze Kings") 36.5 31.4
- 1,450 to 1,150 B.C. ("Late Bronze") 39.6 32.6
- 1,150 to 650 B.C. ("Early Iron") 39.0 30.9
- 650 to 300 B.C. ("Classic") 44.1 36.8
- 300 B.C. to 120 A.D. ("Hellenistic") 41.9 38.0
- 120 to 600 A.D. 38.8 34.2
- Medieval Greece 37.7 31.1
- Byzantine Constantinople 46.2 37.3
- 1400 to 1800 A.D. ("Baroque") 33.9 28.5
- 1800 to 1920 A.D. ("Romantic") 40.0 38.4
- "Modern U.S. White" (1982-ish presumably) 71.0 78.5
I am not entirely sure what to make of these figures, but two things seem
to stand out. Longevity decreased slightly during the first several
millennia after the introduction of agriculture when meat consumption went
down and plant foods predominated, then gradually rebounded. It seems
apparent therefore that meat itself could not have been the factor
responsible for decreased longevity since *more* was eaten during
Paleolithic times. On the other hand, the effect does not seem to have been
too pronounced. From some of the later time periods involved where
civilizations were known to be on the rise or fall, it appears that social
factors have the biggest impact on longevity, particularly since longevity
never rose above about age 45 for long, often falling below that figure for
centuries at a time, until the 1900s, since which time it has almost
doubled. That is what impresses me the most.
Also a response here to Mart Johnson and his comments about meat:
>I HAVEN'T HAD TIME TO KEEP UP WITH ALL THE VEG-RAW MAIL LATELY, BUT I
>DID READ ONE OF WARD'S LETTERS TO BOB AND I HAVE A FEW COMMENTS. IT IS AN
>ESTABLISHED FACT THAT FOR THOUSANDS OF YEARS HUMANS HAVE BEEN EATING MEAT.
>BUT, YOU SEEM TO IGNORE THE FACT THAT FOR MOST OF THIS TIME PEOPLE HAVE
>BEEN COOKING THEIR MEAT. THE HUMAN POPULATION HAS NOT ONLY SURVIVED BUT
>EXPLODED. IT IS TRUE THAT ALL KNOWN PRIMITIVE PEOPLE EAT MEAT, BUT THEY
>EAT IT COOKED. I KNOW YOU WERE NOT DISCUSSING WHETHER TO COOK OR NOT TO
>COOK MEAT. HOWEVER, YOUR ARGUMENTS COULD ALSO BE THE BASIS FOR WHY PEOPLE
>SHOULD COOK MEAT. WHY DO YOU BELIEVE PEOPLE SHOULD EAT RAW MEAT WHEN OUR
>ANCESTERS ACT IT COOKED.
I agree it may be true that if one looks only at modern primitives, they
eat a good deal of their meat cooked, at least I think this is the case for
Aborigines. I am not so sure it is the case for all modern primitives. The
other thing is that modern primitives are just that: modern, and thus while
they can give clues to past behavior (the Eaton research team used this
approach where foraging behavior was concerned to estimate a meat intake of
35% of the diet during late Paleolithic times from 40,000 years ago to the
present), there are limits to this approach.
Actually, hominids (humans and proto-humans) have been eating meat for at
least 2-3 million years, and most evidence would suggest cooking did not
first begin till the last 500,000 years, and maybe not regularly until some
time after that (125,000 years ago is the best estimate I have seen). So
during the bulk of that time they would have been eating the meat raw. I
understand from looking through the literature on this question that even
where meat was cooked during this time, it still would likely have been
eaten raw at the kill (or scavenge), then since not wasting anything was
important to survive, what was not eaten would have been cooked, dried
(whatever) to preserve it for maximum utilization. Thus, it appears that
there actually would have been a mixture of both fresh-raw and also cooked
meat eaten in recent evolutionary times.
>I BELIEVE THE TYPE OF FOOD WE EAT CREATS OUR CONSCIOUSNESS. NOT EVERYONE
>WANTS
>TO BE ON THE SAME PLAIN. I LIKE TO EAT RAW VEGAN FOODS BECAUSE I LIKE THE
>WAY IT MAKES ME FEEL, THE TYPE OF ENERGY IT GIVES ME. IT IS INTERESTING TO
>STUDY OUR PAST, BUT I AM NOT INTERESTED IN RECREATING THE LIFESTYLE OF OUR
>PRIMITIVE ANCESTOR. I AM INTERESTED IN MOVING FORWARD. DON'T FORGET THAT
>PRIMITIVE MAN ONLY LIVED TOPS ABOUT 30 YEARS.
I believe food does have some impact on consciousness. For me it has mostly
been on my mood level as mentioned before. If you can maintain good health
on a vegan diet, Mart, and you like the effect on your consciousness, then
go for it. All I am saying is that vegan diets are not "natural," if by
natural one means to follow humanity's "original" diet. But then, evolution
is open-ended. If we all want to start eating vegan diets, or cheeseburger
diets :-), or whatever, the species could eventually adapt if it persisted
long enough. (Odds are, given not-total-compliance and much resistance
among substantial sectors of the population, though, it would take a good
10,000-20,000-30,000-40,000 years if not more, at least from what I know of
rates of evolutionary change.)
Oh, and about the Eskimos early deaths. The Americas were only colonized at
the earliest around 12,000-13,000 years ago. I don't have any sources right
in front of me now, and these figgers might be somewhat off, but I believe
the Eskimos have only been in the Arctic something like 3,000-4,000 years,
maybe not quite that long. This is very little time to adapt. While
undoubtedly some adaptation has taken place in that time, it is probably
not complete, and they are likely still reaping the fallout of their
incredibly high meat diets (about 90% meat before assimilation into modern
culture), far above the late paleolithic average thought to be 35%. I think
Doug is right their health and longevity would improve if they were to
substantially decrease the meat in their diets.
--Ward Nicholson <[log in to unmask]> Wichita, KS
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