Re: Evolution of human diet

pete (VINCENT@REG.TRIUMF.CA)
28 Nov 1995 20:59:29 GMT

This is a little late, ubc was throttling articles yesterday...

Osmo Ronkanen (ronkanen@cc.Helsinki.FI) sez:
`In article <wardnik-2211951042140001@204.95.83.113>,
`Ward Nicholson <wardnik@southwind.net> wrote:
Many of the people [...]
are convinced that homo sapiens was "originally" (whatever
`>that means) a vegetarian species, even a so-called fruitarian species that
`>ate nothing but raw foods and so that is what we should be doing today.
`>

`Hardly likely. How did Neanderthal men live on winter for example.
`Modern man is so accustomed to the idea that he can at any time go to a
`supermarket and get all imported vegetables he needs, but just 100 years
`ago things were very different. Let alone before agriculture.
`Ideological vegetarianism is a 20th century luxury that people in the past
`could not afford.

Except that depending where you put `originally', his statement is
essentially true. As his chronology later in the post showed, he
was talking fructarian around 20Mya, which is a reasonable speculation.
Our dentition and alimentary system have not evolved far since that
time, and are still appropriate for a diet of nuts and berries.

We are now much more omnivorous, and have been moving in that direction
for at least 5My, but for perhaps the last 2My, we have had the benefit
of some degree of culture to aid us in modifying our food, so that we
could expand our diet rapidly beyond what we were physically able to
deal with directly, as per Julian's post.

`>Starting from the premise that health is far more likely if we eat foods
`>that are in line with our biological adaptation, one idea would be to
`>discover just what humanity's "original" or "primitive" diet was and
`>follow it.

`That makes no sense, as the level of physical activity can be very
`different now (either lower or higher depending on the person). Second
`people are now healthier and live longer than ever. In the west we can
`eat what is really healthy to us (or what tastes good :-) ) instead of
`what we can get.

I don't think it's so unreasonable. We just have to understand that
the diet of our ancestors 20Mya is not therefor appropriate for us.
I believe our digestive systems have been selected over time to
cope with what we've thrown at them, and are probably best suited to
the kind of diet we had say up to about 1 or 2 hundred thousand
years ago. My reasoning is that I don't really think that we could
evolve sufficiently rapidly to cope with the changes in our diet
over the couple of 10^5 years, when cultural influences have become
dominant. The effects of culture on diet are known to have been
radical over the last 10K years, and I wouldn't want to have to
speculate on what occurred over the 1-200K years previously. But
prior to that, it _might_ be more reasonable to expect that culture,
and therefore diet, evolved much more slowly, and were reasonably
stable long enough for physical evolution to achieve something
like an equilibrium.

What might that diet have been like? Out where I live, I look to
the bears to get some idea. Although their claws and teeth give
them access to food sources we might not achieve unaided, our
primitive toolset would likely have made us their equals. And
bears seem to have dietary preferences similar to ours. In the
summer, their droppings seem to consist sometimes entirely of
berries. In the fall, they line up on the river banks for a
salmon feed. They like rooting grubs out of decaying fallen
trees, like many rainforest peoples, and of course are reknowned
for seeking out honey. (They also love human food from garbage
dumps, but that's a bit off topic).

Before our ancestors learned to modify their environment
to produce food for themselves, they would have faced the same
challenge feeding themselves that the bears do, and probably
responded similarly. They also were likely smart enough observers
to watch animals like bears, sea otters, and raccoons, to see
what they were eating, and follow suit. Last summer while I sat
quietly on a rocky shore, after midnight on Desolation Sound, I
watched a small marine mammal, maybe a sea otter, maybe a harbour
seal, slide quietly by me, visible only from the phosphorescence
it stirred in the water. It beached about two hundred metres from
me, and I listened as it crunched about on the shore, for about
forty minutes, before slipping back into the water and returning
the way it came. The next morning, I walked over to where it had
been, and found a rich oyster bed, where it had obviously been
feeding. I collected enough for a fine feast for my son and myself
(we were camping by kayak). I expect this is how people and
pre-people managed wherever they travelled, being smart, versatile,
and keen observers and opportunists.

--

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    vincent@triumf.ca   <== faster       %    Pete Vincent

    vincent@freenet.vancouver.bc.ca      % Disclaimer: all I know I

                                         % learned from reading Usenet.