>Mon, 16 Aug 1999 21:36:10 -0400 Todd Moody wrote:  For those who do not
read the Paleodiet Symposium, the following URL was recently posted on the
use of fire for cooking plant foods:
http://cnn.com/HEALTH/diet.fitness/9908/11/science.cooking.reut/

>If the scientists,,, in the article are correct, the use of fire for
cooking goes back almost 2 million years,,, it has profound implications
...since it means that the "naked with a sharp stick" principle must be
abandoned in favor of the "stone, spear, and fire" rule.  This adds many
foods to the menu, especially foods that can be roasted without a lot of
other processing involved.  1.9 million years is a long >time.

My husband, Don, wrote a lengthy response.  Here's the short version.  Visit
the Paleodiet Symposium for the version with the citations and all that!
Wrt the article on cooked vegetables "Early humans got smart by cooking
veggies, study says":  This idea that we got smart by cooking vegetables,
not by hunting and meat eating, may be politically correct, but it is
illogical and biochemically incredible.  Here are my reasons:

1)   Cooking is a highly sophisticated behavior that requires intelligence
not had by any other primate.   No non-human primate cooks.  Our closest
primate relatives, the chimps, do hunt.  Therefore, hunting definitely
preceded cooking.  The "advance" from eating everything raw to using fire
for cooking had to wait for improvements in brain capacity, hand eye
coordination, manual dexterity, etc.  In other words, cooking could not have
become common activity for man until after his nervous system had developed
beyond that of the chimps.   Hence, cooking must have come after man became
"smart"--in other words, man did not become "smart" by cooking, he started
cooking after becoming "smart".

2)  Further, there is nothing in cooked vegetables that would support
development of a more sophisticated nervous system or brain.  The primary
structural material of the brain is the omega-3 EFA known as DHA
(Docosahexaenoic acid).  There are no vegetables that provide DHA.  Greens
provide alpha-linolenic acid, which some animals can convert to DHA, but
modern humans have little or no ability to achieve this conversion.   Chimps
also obviously have no marked ability to achieve this conversion--if they
did, they'd probably have bigger brains.  In fact, there is no mammal that
is capable of making enough DHA from scratch to produce a large brain.  So
there is no reason to believe that early man had any ability to make large
amounts of DHA out of the alpha-linolenic acid (ALA) found in green leaves.
Furthermore, it has been estimated that even in the best of ALA converters,
it takes 10 grams of ALA to produce just one gram of DHA.   The absolute
amount of ALA in green leaves is very small, on average less than one half
gram per 100 gram portion, so literally enormous amounts of green leaves
would have to be eaten to get significant amounts of DHA.  Mankind simply
does not have the kind of gut needed to process that amount of greens.
Finally, ALA is heat-labile, so cooking greens would have destroyed much of
the value of ALA.

3)  The authors of this "research" say "We don't see meat as a high energy
food source.  It has to be (a) high energy food source to explain this
doubling of body size."  If they don't see meat as a high-energy food source
and think that cooked vegetables are high-energy foods, I suggest that they
try living on nothing but cooked vegetables for a few weeks.  Here are some
facts:

Energy value for one cup portions (one cup of raw meat is approximately 8 -
9 ounces):

Food                                            Calories

Cabbage, cooked                                32
Kale, cooked                                     40
Broccoli, cooked                               50
Pumpkin, cooked                                50
Onions, cooked                                 60
Carrots, cooked                                70
Winter squash, cooked                      110
Sweet potato, boiled and mashed        364

Nuts, raw                                       933

Eggs, eight medium raw                     640

Wild game, raw, lean only                  232    (Average, taken from
Eaton, et al Paleolithic Prescription)

Beef brains, raw                              392

Animal fat, raw                               1840    (This would represent
marrow,  storage fat, etc.)

From these figures it is hard to understand how the authors of the "study"
in question could conclude that cooking vegetables gave early man access to
"high energy" foods.  My guess is that the authors have not looked at energy
density in terms of volume, i.e. calories per cup, but have been misled by
looking only at calories per gram.   If you look at calories per cup, the
only vegetable that on a cup for cup basis comes near to the energy value of
wild game lean meat is the tuber sweet potato.  A hunter gatherer would have
to eat two cups of cooked winter squash, over three cups of cooked carrots,
nearly four cups of cooked onions, or nearly six cups of cooked green leafy
vegetables to equal just one cup of raw lean meat.   Brains are higher in
fat, so they are almost twice as energy dense as lean meat; the fat content
of brains is not affected by feeding practices--the brains of wild game are
just as rich in fat as are the brains of domesticated cattle.  Eggs also are
much more energy dense than vegetables.  Further, it is known that not only
aboriginal people but also chimpanzees eat raw brains and eggs when they can
get them.   So we don't have to guess that maybe early man ate those
things--it would be odd if he didn't.

Now take a look at nuts--which are mostly fat-- and animal fat--THERE IS THE
ENERGY DENSITY REQUIRED!  Again, it is known that both chimps and aboriginal
people eat marrow and kidney fat.  But "primitive" people eat more meat and
more fat than chimps.

The idea that cooking vegetables was the key to a high energy density diet
is absurd.  The easiest way for a primate to get a high energy density diet
is to EAT BRAINS AND MARROW FAT.  This is also the best way to increase
intake of linoleic acid, EPA, DHA, and other fats needed for development and
maintenance of sophisticated eyes, brain, nervous and vascular systems.

But eating brains and marrow fat is politically incorrect these days.  With
all the popular hysteria about the dangers of eating organ meats and fat,
who is going to publish a head-line stating that "EARLY MAN DEVELOPED A BIG
BRAIN BY EATING BRAINS AND FAT, STUDY SAYS"?

This is one of the worst examples of junk reporting and junk science we've
seen in a while.  By presenting this half-baked politically correct
supposition to the public before the scientific community has an opportunity
to comment upon it, the authors of this supposed research will be patted on
the back, and their "conclusions" will be by many laymen accepted as
"fact"--after all, it is very unlikely that Reuters will in a few days
publish with bold headlines all of the logical and biochemical objections I
or any one else will have to their mistake.

Don Matesz

Sorry, it's so long..... Rachel Matesz ;-/