Paleo Phil wrote:
>> Can you name a
>> single hunter-gatherer people which never eats cooked food? 
  
William wrote:
> Unlikely that they had any cooked at all during the long Arctic winter, 
> as they had no fuel other than the moss used for female "hygiene",  and 
> if we consider the easily observed results of eating cooked, why would 
> they bother?

Actually, the Inuit had seal and whale oil to heat and cook with during the
winter, which was their main fuel source. It was also used during the summer
(such as when they coated bones with the oil and used the oiled bones to
make cooking and heating fires).

So you can't think of a single people that never cooked their food? Not even
the healthy traditional Inuit or Nenets or other hunter gatherer groups that
are pointed to here as paragons of good health? Well, that's not surprising,
because even Vilhjalmur Stefansson talked about Inuit cooking and heating.
Here are some examples from Adventures in Diet by Stefansson:

> "They themselves ate boiled fish."

> "In the morning, about seven o'clock, winter-caught fish, frozen so hard
that they would break like glass, were brought in to lie on the floor till
they began to soften a little. One of the women would pinch them every now
and then until, when she found her finger indented them slightly, she would
begin preparations for breakfast. First she cut off the head and put them
aside to be boiled for the children in the afternoon...." 

> "Also we came home to a dwelling so heated by the cooking that the
temperature would range from 85 degrees to 100 degrees F. or perhaps even
higher - more like our idea of a Turkish bath than a warm room. Streams of
perspiration would run down our bodies, and the children were kept busy
going back and forth with dippers of cold water of which we naturally drank
great quantities."

============

Geoffrey Purcell wrote: Whether any native-tribe eats a 100% raw diet or
not, is irrelevant. 

It is very relevant as part of an analysis of your claim that "it is highly
unlikely that tubers were a significant part of the diet before c.250,000
years ago, when cooking was invented." The three main areas of evidence re:
diet that are looked at are 1) what traditional hunter gatherers encountered
in modern times do/did, 2) what the paleontological/archaeological record
shows and 3) morphological changes in human anatomy. 

1) Modern hunter-gatherer diets and practices:

The fact that No hunter gatherer tribe has ever been encountered that eats a
100% raw diet means that your claim is not necessarily established beyond
all doubt in the first area of evidence. Plus, if cooking was a serious risk
to health, as William sometimes suggests, we would expect to find at least
one hunter-gatherer tribe over the last 100,000 years that only ate raw,
given that in the wild only the fit tend to survive and procreate. Also,
there are multiple hunter gatherer tribes who cook and eat wild yams (such
as the San bushmen, the Yanomamo, the Hadza and the Australian Aborigines).
You can read about hunter-gatherer cooking practices and mention of yam
consumption here: "Cooking practices of hunter-gatherers,"
http://www.beyondveg.com/tu-j-l/raw-cooked/raw-cooked-3e.shtml.

Vis-a-vis those who advocate a 100% raw Paleo diet (and I'm not saying that
anyone here necessarily does). If raw eating is so essential and cooked food
so unhealthy, how is it that the healthy Inuit, and even the Nenets, ate
some of their food cooked even before civilization encroached on them? All
I'm saying is that it may not be necessary to be so extreme about the diet.
Raw is good, but it doesn't appear necessary to be 100% raw.

2) The paleontological record:

In the second area of evidence, digging sticks that could have been used to
dig up yams have been found going back hundreds of thousands of years. 

Solid evidence of hearths, "with stones or bones encircling patches of dark
ground or ash," has been dated up to 250,000 years ago in several sites in
southern Europe. Charred bones, stones, ash, and charcoal dated 300,000 to
500,000 years ago and found at sites in Hungary, Germany, and France have
also been assigned to hearths. [Food for Thought, by Ann Gibbons, Science,
15 June 2007,
http://www.sciencemag.org/cgi/content/full/316/5831/1558?ijkey=qZN/4mNiv/hng&keytype=ref&siteid=sci]

The earliest evidence of controlled use of fire comes from various
archaeological sites in East Africa, such as red clay shards dated back 1.42
million years before the present. [James, Steven R. (February 1989).
"Hominid Use of Fire in the Lower and Middle Pleistocene: A Review of the
Evidence". Current Anthropology (University of Chicago Press) 30 (1): 1–26.
doi:10.1086/203705, http://www.journals.uchicago.edu/doi/abs/10.1086/203705]
The idea that cooking was not adopted until a million or more years after
the controlled use of fire seems highly dubious.

3) Morphological changes in human anatomy:

In the third area of evidence, Wrangham points out that there were
morphological changes (such as decline in jaw and teeth size) in
proto-humans some 1.9 million or more years ago that suggest the adoption of
a softer diet, due to either the cooking of foods or a switch to softer,
easier-to-shred-and-chew foods. I remain skeptical of Wrangham's arguments,
but I cannot dismiss them without providing counter-evidence.

When we look at the fact that the last major human morphological changes
occurred around 100 - 150,000 years ago and that Eaton, Cordain, Audette and
others believe that the human foods of this time period are therefore the
ones we are best adapted to, and that this was well after the 250,000 years
ago that Geoffrey mentioned, cooking tubers does not seem so far fetched
after all. I don't know whether yams and other tubers were staple Stone Age
foods or not, but the cooking argument falls flat in the face of
overwhelming evidence.

My current guess is that yams and other tubers were generally "fallback
foods" (and Wrangham even calls them this). So, even though they were
probably cooked and consumed by the earliest homo sapiens, and even earlier
proto-humans, they did not become staple foods among large population groups
until closer to 10-30,000 years ago. This would explain why it seems that
modern humans are partially, but not fully, adapted to digesting cooked
tubers. Adaptation to eating cooked meats seems much more advanced, based on
the evidence. However, the evidence regarding cooked yams is still
sufficiently unclear that I cannot rule out that they might have been a
staple food of the Paleolithic era. This would then raise the question of
why we don't seem to be fully adapted to them.

Here is more from Wrangham and Greg Laden:

<<We propose that a key change in the evolution of hominids from the last
common ancestor shared with chimpanzees was the substitution of plant
underground storage organs (USOs) for herbaceous vegetation as fallback
foods. Four kinds of evidence support this hypothesis: (1) dental and
masticatory adaptations of hominids in comparison with the African apes; (2)
changes in australopith dentition in the fossil record; (3) paleoecological
evidence for the expansion of USO-rich habitats in the late Miocene; and (4)
the co-occurrence of hominid fossils with root-eating rodents. We suggest
that some of the patterning in the early hominid fossil record, such as the
existence of gracile and robust australopiths, may be understood in
reference to this adaptive shift in the use of fallback foods. Our
hypothesis implicates fallback foods as a critical limiting factor with
far-reaching evolutionary effects. This complements the more common focus on
adaptations to preferred foods, such as fruit and meat, in hominid
evolution.>> Tuber or not tuber? Rats are the question,
http://johnhawks.net/weblog/reviews/early_hominids/diet/laden_wrangham_tuber_2005.html

=====

As far as the Inuit diet being an extreme outlier as compared to the
majority of Paleolithic diets, I believe Steve is right about that, as I
mentioned before. The Inuit diet is not the only hunter-gatherer diet and is
not representative of the majority of hunter-gatherer diets of either the
modern or Paleolithic eras. I think some people mistakenly equate the
(Greenland) Inuit diet with the Paleo diet because Ray Audette and
Stefansson featured it. It is only one of many hunter-gatherer ways of
eating. Some people do not realize that even among the Inuit and other
Northern Canadian tribes there was diet variation. Some ate more berries and
other plant foods than others, depending on what flora and fauna were
available in their particular latitude and geography.