The level of your dialogue is fantastic and I greatly appreciate it.  Having said that, I hesitate to add these comments as I don't want to lower the level of the debate (and, BTW, how refreshing to open my email and read serious, thoughtful debate on real issues like human evolution and diet as opposed to Britney Spears etc. nonsense.  Even though I'm a bit of a lurker, I do really appreciate reading).
It seems to me that people (now or then) regardless of situation would try to eat just about everything.  What wouldn't we put in our mouths and eat?  I think the standards for what might have constituted a "normal" paleolithic diet would have to include - whatever you could find.  And this would include grains as well, albeit not in the form or amount that our (speaking of the US here) corn-based modern diet where "whole grain" is synonymous with "healthy" even to the extent that I watch ads on tv telling you to give your cat or dog a "healthy" diet of "whole grains" (I just shake my head in wonder).  And it would have to include things that we may not consider eating now - like worms, and insects and grubs.
Of course we (our genetic ancestors) ate tubers.  Of course we ate every damn thing we could get our hands on.  Some were good for us - and some were not.  But we ate them anyway.  You would really have to present to me some profound evidence (like multiple genetic examinations of stomach content somehow preserved) that could prove that we didn't eat these things.  (I know - can't prove a negative).
The question, it seems to me, is not did we eat these things, but rather are these things good for us?  Are they healthy given what we know (unfortunately what the broader society ignores or doesn't know) that a grain-based, sugar-based diet is not good for us (and particularly destructive to some of us like me) and that a diet based on healthy animal-based protein, fruits and vegetables is good for us.  
I love this debate.  I love learning about tubers.  I love eating (some) tubers - give me yellow beets and turnips everyday and I'm happy.  But to think that paleo us did not eat certain items that would have been present in their environment is a difficult concept for me to swallow (yeah, a bad pun - I know).
gale



----- Original Message ----
From: Todd Moody <[log in to unmask]>
To: [log in to unmask]
Sent: Wednesday, May 14, 2008 10:36:19 AM
Subject: Re: Stone-age diet may lower risk of heart disease

Geoffrey Purcell wrote:
> If you read about the various famines in the last 60 years, you'll find that one of the big 
> reasons why some underdeveloped  countries  have them so frequently is that they are 
> too dependent on one or two 
> staples(usually poor foods such as tubers, like cassava etc- cassava contains cyanogenic 
> compunds so must be fermented, grated and left out in the sun so that the cyanide can 
> evaporate, it also needs to be cooked beforehand, and has been linked to the deficiency-
> disease kwashiorkor.) The trouble with tubers is 
> that they commonly have antinutrients in them, and are deficient in a number of key  
> trace nutrients, so become a problem if consumed in more than trace amounts. The other 
> point is that the DHA hypothesis holds that it's the DHA in meat that helps to  increase 
> brain-size(tubers don't contain DHA in remotely significant amounts, last I checked).
>  

My question was, why would tubers only have been eaten in famine times?  
These observations, while correct, don't answer that question. Virtually 
all plant foods, including the paleo ones, have so-called "secondary 
compounds" (toxins and antinutrients) to some degree, including 
strawberries, peaches, spinach, broccoli, radishes, cauliflower, 
cabbage, and collard greens--all of which contain goitrogens.  Spinach 
and rhubarb also contain oxalic acid, another antinutrient. So the mere 
presence of antinutrients in foods doesn't make them either inedible or 
nonpaleo.  The fact that a given food, such as peaches, is devoid of DHA 
certainly isn't sufficient to make it nonpaleo.  There's no reason to 
believe that these foods would only have been consumed in trace amounts, 
despite the presence of antinutrients in them.

I ask this not because I advocate a tuber-based paleo diet, or because I 
think tuber consumption is what drove the evolution of the brain.  The 
question is simply: Should a (modern) paleodiet include any tubers?  The 
answer to that questions is generally understood to be that a modern 
paleodiet should include only foods that were a normal (not necessarily 
dominant) part of the actual diet of paleolithic people.  So the 
question isn't, Did paleolithic people have a tuber-based diet.  I agree 
that the answer to that question is no.  The question is, rather, Did 
paleolithic people normally eat tubers, not as desperation famine food, 
but as part of their diverse foraged food supply?  I see no reason to 
think that the answer to this question was no.

The difference between edible and inedible plants is that the edible 
ones have lower levels of secondary compounds; they are not necessarily 
devoid of them.  Cooking lowers the levels of secondary compounds in 
otherwise inedible plants to levels comparable to those in plants that 
are edible uncooked.  The only diet that would be devoid of secondary 
compounds would be an all-meat diet (but no raw eggs!).  While this is 
certainly an option, I think nobody would suggest that a paleo diet 
*requires* it.  And since cooking (not just fire) extends well back into 
the paleolithic era, to before the appearance of modern homo sapiens, 
cooking is paleo.  That doesn't mean that a paleo diet entails cooking, 
but it does mean that it includes it.  Cooking made more foods available 
by making more plants edible, and it did so in indisputably paleo 
times.  So the "edible raw" criterion of paleo doesn't line up very well 
with what actual paleolithic people were probably doing for the last 
quarter million years or so.


Todd Moody
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