Great post, as usual, Todd. It summarizes the issue well. Thanks for the
input.

> >  Todd, wrote:
> ....
> World food.  Actual yams originated in tropical Africa.  So it all 
> depends on your definition of "paleo."  One reason why I 
> don't post much 
> anymore is that I got tired of arguing about that definition, because 
> the various positions (including mine) are so underdetermined by the 
> available facts.
> 

"Evolutionary" diet may be a clearer term than "Paleolithic" diet. A Paleo
diet could be the foods that Paleolithic people ate (and people disagree
over the optimal time period to look at), or the food categories they ate,
or the basic types and ratios of foods they ate. An evolutionary diet is
much simpler to define--those foods to which humans have biologically
adapted (though there is still plenty of room for argument over which foods
humans have adapted to). However, "evolution" is a more controversial term
than "Paleolithic" and evolutionary is more of a mouthful than Paleo
("biologically appropriate" is even more so).

> 1. If paleo = edible raw, then yams are not paleo (but sweet 
> potatoes are). 2. If paleo != any New World food, then sweet 
> potatoes are not paleo. Therefore, if 1. and 2. are true, 
> then neither yams nor sweet potatoes 
> are paleo.
> 
> Personally, I am very impressed by the Aiello/Wheeler 
> "expensive tissue 
> hypothesis." (Nice article, 
>
http://www.scielo.br/scielo.php?pid=S0100-84551997000100023&script=sci_artte
xt)  
> The basic idea, that the growth of the hominid/human brain required a 
> higher "quality" diet, i.e., more calorically dense, is consistent with 
> both the increased consumption of meat (preferably fatty) 

The authors do mention meat and "high quality diet" but they don't
specifically mention "calorically dense". Do they mention this elsewhere or
do they assume that the reader understands that "high quality" implies
"calorically dense"? I know that I have seen caloric density implied by
terms like "high quality" and "energy rich" elsewhere (such as in the
observations of Katharine Milton at
http://www.discover.com/issues/may-95/features/gutthinking503 where high
quality and energy rich means fruits and meats, vs. energy-poor leaves). 

> and Wrangham's tuber hypothesis.  

My guess is that the author's would agree with that, but is their hypothesis
necessarily consistent with the tuber/cooking hypothesis? The only food
mentioned in the abstract is meat: "the importance of a high quality diet,
and meat eating in particular, has been a common theme." The authors didn't
mention tubers or cooking. It depends what the authors mean by "high
quality". If "high quality" means "calorically dense", then the theory could
be consistent with Wrangham's cooking/tubers hypothesis.

> I don't see the two as in competition.  I imagine 
> paleo people exploited edible tubers, rhizomes, etc, starting with those 
> that are edible raw.  The invention of cooking (certainly a paleolithic 
> invention) would have made other tubers, such as yams, exploitable.

I think that Paleolithic people in Africa likely consumed some yams because
I can't imagine them not doing so once they started cooking food (which most
scientists believe started well over 125,000 years ago). Since yams were not
edible raw (and still are toxic raw) they did not eat them raw and only
started eating them once they could cook them. Meat, on the other hand, they
started eating raw (and the species they evolved from also ate some raw
meat/organs) and then later on also ate some cooked, while continuing to eat
some raw. So humans could easily be adapted to eating both cooked and raw
meat, but still have obviously not adapted to eating raw yams. It's possible
we could have partially or fully adapted to eating cooked yams--my guess is
the former.

I agree with you that the cooked meat and tuber hypotheses do not have to be
seen in competition. In addition to caloric density, meat and cooking have
behavioral effects (cooperation, sharing, division of labor, specialization,
wider range) that also could have contributed to evolution of larger brains.
Tubers by themselves do not seem to have these effects.

> I never heard of eating bees before.  I asked her if she would eat them
again, and she said they tasted good but now that she knows what they are,
no. 

I mentioned in a few recent posts that some traditional peoples still
consume honey bee products as a regular (mostly seasonal) part of their
diet, with all of them apparently savoring the bee larvae (brood) more than
the honey. Interestingly, honey bears also reportedly prefer the bee larvae
over the honey and will eat the brood first.

Insects may be a key food for the future. The fact that the world does not
have the capacity to produce enough meat and vegetables to feed the world is
the biggest problem with the Paleo diet. Ray Audette mentioned that insects
are the highest-quantity Paleo food on earth (with 9 lbs. of termites for
every human) and could some day in the far future become a cheap AND healthy
(termites, for example, contain very healthy fats) food for the poor and
starving of the world (much better than the wheat flour, corn, rice, etc.
they give them now), once they figure out how to farm insects on a large
scale and mass produce food products from them.