From: gts (gts_2000@yahoo.com)
Date: Mon Apr 21 2003 - 10:30:13 MDT
Harvey Newstrom wrote:
> However, I still have a few problems with the Paleo diet theory.
>
> 1. Why are beans left out? I don't buy the part about not being able
> to soak them. Why do we suppose our ancestors had simple tools for
> hunting (spears, sticks, knives, axes, pits, etc.), but couldn't come
> up with bowls, for example. I also don't buy the part about not being
> able to eat beans or legumes raw. I love munching on raw peas out of
> the garden, and the Japanese have a long history of eating soybeans
> cold and raw out of the pod. These things are easy to eat and digest.
Legumes (and grains, yeast and dairy) contain lectins, which are thought to
cause or aggravate auto-immune diseases like rheumatoid arthritis and
ulcerative colitis. Lectins are glyco-proteins evolved by plants to ward off
insect predators. It is known that lectins attach themselves to the walls of
the gut and increase intestinal permeability, allowing partially digested
food proteins and remnants of resident gut bacteria access to the blood
stream. In the words of Loren Cordain Ph.D., lectins are "cellular Trojan
horses."
See http://bmj.com/cgi/content/full/318/7190/1023. This is an article by an
allergist who has no particular interest or axe to grind with regard to
paleodiets, but who, like Cordain, sees lectins as a possible cause of
disease.
If there is any question, then of course paleodiet theorists reject legumes
simply because they were not significant parts of prehistoric human diets,
suggesting that we can't be well-adapted to them. Remember that paleodiet
theorists start from the premise that we should not eat foods to which we
are not well-adapted. I would like to see some evidence that the Japanese
have been eating raw soybeans in any significant quantity for any
significant time. As far as I know, soy beans are practically indigestible
unless they are processed and made into foods like tofu.
> 2. Why are grains left out? Same thing. Everyone seems to admit
> that grains grew wild all over the place.
See above regarding lectins. Also, the fact that wild grains were present
does not mean they were important staples of the prehistoric diet. I do not
doubt that prehistoric peoples chewed occasionally on wild grains when they
were hungry and could find nothing more flavorable and nutritious to eat,
but many such seeds are too hard to chew. There was some grinding of wild
seeds on primitive millstones in the late paleolithic or mesolithic, but the
evidence is clear that wide-spread cultivation of grains, in which the seeds
were planted and harvested in great number, did not arise until Neolithic
times. Indeed agriculture is largely what defines the Neolithic.
> The argument is again that ancient tools couldn't handle them.
That's not really the argument. The argument is that, for whatever reason,
*agricultural technology* did not arise until the Neolithic and so grains
did not become an important part of the diet until the Neolithic. This is
evidence from archeology. Farming of any did not exist until recently.
> 3. Speaking of not having bowls, this Paleo Diet seems to assume that
> everything needs to be cooked using an open flame. Modern knowledge
> tells us that this is the worst way to cook foods, especially meats.
> Charred food or even fire-cooked foods are more carcinogenic. While
> this may not have bothered our ancestors who died at an early age, it
> certainly bothers me when I want to live well past 100.
Yes, I agree. Apparently you missed my discussion with Brian Atkins here in
this thread on that subject. Many paleodieters broil or boil their meats or
cook them very lightly over low-heat to minimize the (possible) carcinogenic
risks of HCA's. As Brian pointed out the evidence that HCA's are
carcinogenic is not unequivocal, and as I pointed out this is a perfect
example of an ambiguity of nutrition science. Paleodieters attempt to settle
the debate re: HCA's with evolution science. And even then there is room for
debate, depending on when one believes fire-cooking fist appeared as an
important part of the human diet.
> 4. I agree that humans are naturally omnivores, eating meat and
> vegetables. But the meat-eating seems a bit exaggerated. It is not
> obvious or proven that the ancient ancestors ate huge amounts of meat
> every day. They probably had meat a few times per week, and foraged
> for nuts, berries, and vegetables the rest of the time. Their diet
> was mostly vegetarian every day, with boosts of meat occasionally. I
> don't see why this theory is so down on vegetarianism, when it clearly
> supported humans most days.
The studies of hunter-gather cultures I've seen suggest that HG peoples
consumed as much as 60% or more of their calories from animal sources, even
if they did not eat animals every day. Keep in mind that this includes
calories from fats and organs as well as from muscles. A single wooly
mammoth could feed a small tribe for several weeks.
> 5. Speaking of vegetarianism, most of the complaints against
> vegetarianism have nothing to do with modern day. First of all, if
> someone isn't a total vegan, meaning they also eat milk, dairy and
> eggs, then they are not missing out on all the animal-only nutrients.
> Plus, we have supplements today. Any modern person taking a well
> rounded supplement won't have any of the deficiency problems. Plus,
> we can mass produce food in ways never available before. Maybe the
> ancients couldn't mass produce tofu enough for their diet, but the
> corner grocery store can. Most of the anti-vegetarianism
> stuff I read here is aimed at theoretical diets that don't
> exist any more, or aimed at pseudo-scientific claims that
> have nothing to do with a life-extensionist diet that avoids meat.
This is basically a nutritional science based approach to "designer diets,"
and while I don't reject nutrition science out of hand, (I'm a LEF member
and a customer), I also believe nutrition science is incomplete and fraught
with contradiction.
Getting back to my null vs competing hypothesis arguments, I believe we
should start from the premise that the paleolithic diet is the optimal diet
*and then build on it* when we find strong evidence from nutritional science
for non-paleo additions/subtractions to the default paleo diet. I take many,
many non-paleo supplements and medicines myself, but the "base" of my diet
is paleolithic.
>
> 6. I agree totally with the part about ancient lean meats being much
> healthier than the fatty meats we produce today. That is part of the
> reason I am vegetarian, and part of the reason I don't eat a lot of
> meat to duplicate the Paleo diet. Modern meat is dangerous, fatty
> stuff.
Yes. I have a list of about 20 sources of natural range-fed and wild game
meats and eggs that ship by mail-order. Let me know if you would like it.
Range-fed and wild game meat is much leaner, with the proper balances of
important fats like omega-3 and 6, whereas farm-fed beef is overly fat and
overly rich in omega-6 from the high omega-6 non-paleo corn upon which it is
raised.
> 7. As for the idea that we are "adapted" to the Paleo diet, I think
> there is a lot of confusion as to what "adaptation" is. It rarely
> involves mutations or genetic changes of thousands of years as most
> people think. Adaptation occurs in one or two generations when all
> those not adapted to survive die off, and only the survivors have
> offspring into the next generation. We have had dairy, tofu, grains,
> bread, and agriculture for thousands of years. Anybody not well
> adapted to these diets died of millennia ago. I am not sure why
> anybody would think that a modern person today would be well
> adapted to a diet that disappeared so long ago.
Consider for example that most of the world is lactose intolerant because
most of the world has not yet adapted to dairy. Milk is consumed mostly by
people of European descent, because dairy originated in Europe and the
majority of people of European descent have adapted to it, but lactose
intolerance is still a significant problem even among people of European
descent!
Gluten from wheat is also big problem for a lot of people. And I've already
mentioned lectins from grains, dairy and yeast. More evidence is that many
people have problems with casein (dairy protein). Casein is the most
difficult to digest of all types of protein.
While some people can eat practically anything, there is plenty of evidence
that we are not yet as whole adapted to a non-paleo diet.
> 8. Even if the Paleo Diet were the perfect diet we are adapted
> towards, there is a big question as to what that adaptation is set to
> maximize. Evolutionary pressures do not push for longevity of
> individuals.
Yes, this is why I am always open to improvements on the paleodiet, and why
my personal diet includes many non-paleolithic substances. I agree
completely with mez in this thread, who pointed out that in prehistoric
times the forces of natural selection would have been blind to many of the
modern diseases of aging. The difference between my point of view and that
of others here (perhaps also yours) is that I believe the burden of proof is
on those who would ask us to add or subtract something from the paleodiet.
They need to show me the evidence that doing so is beneficial. In many cases
they have done so. I take for example 2500 mg of vitamin C each day. I've
never calculated it, but I would guess 2500 of C is probably as much or more
C than our prehistoric ancestors consumed in a month.
-gts
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