> I would have a few questions and comments on part 2:
> ** Do the percentages (50% animal food, etc) refer to weight, or calories?

Thanks for bringing that up, Jean-Louis! An obvious question that makes me
realize it was quite an oversight not to have stated which, in the
interviews. The answer is: it's by calories. (I'll make that clear in my
next update to the interviews.)

> ** About the adaptation to cooked food, compared with the adaptation to
> milk: it is assumed that, since it took on average 5000 years for certain
> populations to be lactose tolerant in majority, it is possible that
> 125,000 years were enough for humans to adapt to cooked food. However,
> becoming lactose tolerant is a relatively simple genetic change.

That's right, it is a relatively simple change, which I discuss in the
updates to part 2. My thinking about the cooking question has changed
somewhat since the interviews came out a year ago, after having been made
aware of some additional issues by Loren Cordain, Ph.D. on the Paleodiet
list. More of an open question than I had originally thought.

> All human babies produce lactase, so continuing to produce that enzyme
> into adulthood is not such a big deal (although it already takes several
> thousand years and a lot of genetic pressure). Adapting to cooked meat or
> tubers is probably more complex, since many new chemical species appear
> during cooking;

I'd agree with the first sentence there, but the second one I don't know
about. The assumption there is one I don't know I'd want to make without
more specific evidence. In the original interview, Part 2, I discussed the
observation that some of the detoxification mechanisms of the body work
generically, and don't necessarily require so much fine-tuning. The generic
mechanisms listed in the interview were: constant shedding of surface-layer
cells of the digestive system, defenses against free-radical damage, and
DNA excision repair. (I am frankly not sure exactly what the qualifying
word "excision" means in that last mechanism.)

On the other hand, I've gotten wind of tantalizing tidbits here and there
that the detoxification of certain substances requires very specific
enzymes. (Unfortunately the few people I have heard it from in the past
have never seemed to be able to provide any references for further reading
and digging.) Usually this is brought up in relation to fasting, which
skeptics say may actually slow down the absolute rate of detoxification
since the body goes into conservation mode and does not produce as much of
these enzymes as when eating. (That's as much as I've heard though--all
unconfirmed, too, thank you very much :-( ) The comeback of a natural
hygienist of course would be that even if the absolute rate of
detoxification were slowed, the net rate might well increase since no food
intake or the energy required for digestion activities are taking away from
the detoxification that does occur.

Regarding tubers, Loren Cordain, Ph.D. (the Paleodiet researcher) tells me
that the human gut is not very well equipped to handle raw
starch--digestive efficiency is something on the order of about 25-30% when
the starch is raw, climbs to perhaps 60-70% when cooked--this is for raw
rice, not sure how it applies to tuberous starch (they are different in
character). Also, don't quote me on those figures--I'd have to ask Cordain
directly, or go and do an archive search on the Paleodiet listgroup to
confirm--or you can do the same at:
http://maelstrom.stjohns.edu/archives/paleodiet.html.

> FWIW, there is no (or only very weak) taste-changes in heavily cooked
> foods (and very processed foods).

One thing I would be very interested in seeing is some sort of scientific
evidence as to what the taste-change phenomenon correlates with that
researchers can put hard data on, and which might have some bearing on
toxicity questions, nutrient levels/types in the food, etc. I know there is
theorizing about Maillard molecules from the Instincto camp, but the
instincto literature I've skimmed seems much more speculative than
definitive. I know that sounds skeptical, but as so much that I used to
take for granted in the alternative health world has been disproven or
brought into question by modern research, I tend to approach the
significances of such subjective experiences as the taste-change may have
with a jaundiced eye. Not that I am disputing the taste-change exists, but
objective correlations for subjective experiences have sometimes been shown
or are now suspected to be different by science than what proponents
sometimes like to think.

(A couple of examples: Zinc deficiency may be a much more plausible
explanation of the spaciness that some experience on long-term vegan/
fruitarian diets than that it is a "spiritual high." For another,
hygienists have claimed for years that meat is more difficult to digest and
a more toxic food, yet modern food science shows iron, zinc, vitamin D,
etc., have higher bioavailability, i.e., they are digested/absorbed better
in meat--meaning that despite the fact meat takes longer to digest, the net
return/efficiency is better. I have yet to see any good studies about meat
per se somehow being a "toxic" food by nature--actually I haven't found any
because it's difficult to look. Another question for the Paleodiet list
research cabal, I suppose.)

I did read something recently, though, that said--and I wish I could
remember where I read this; these people didn't know anything about
instincto; this was in a completely different context--geez, the
taste-change is no big deal: just simple habituation effect. Of course,
that doesn't explain why taste changes would be greater with raw than
cooked foods. But, frankly, although I've never experimented with
instincto, I've never had problems knowing when to stop with about any
food: I just don't want anymore, whether by taste habituation effect, or by
fullness, or just plain being tired of the food and it sort of going to
ashes in my mouth and not being as tasty anymore, depending on the case.

(I've always been a little incredulous, as a result, as to how so much is
made over the taste-change. I always thought it was pretty much a universal
experience so common that nobody ever thought to really talk about it much.
You know, like the feeling you get when you have to go to the bathroom! Why
make a big deal about it? :-) Can't you imagine the scenario that would
develop? "Hey Harry, did you read this new book that Jean-Claude Poopie-eh
wrote here? Like wow, it's got a whole new theory about exactly when you
should or shouldn't take a pee or a crap, and the great improvements in
health it will bring! :^) I tell ya, this is an extraordinary phenomenon
that's going to totally revolutionize the science of gastroenterology and
colonic/ bladder health!) hehe :^)

> On the other hand, modern hunter-gatherers can be considered as healthy,
> despite cooking half of their food. My guess is that eating a reasonable
> amount of cooked, but otherwise unprocessed food is acceptable, i.e. we
> are probably "almost" adapted to cooked food (like "almost" all of the
> members of certain populations are now lactose-tolerant). Certainly
> everyone should experiment, and find the percentage or raw s/he is most
> comfortable with.

One of the points brought up in the postscripts is that since modern
hunter-gatherers on average seem to cook about half their food (I have a
reference for this on the aborigines about this, not completely sure about
other H/Gs), and H/Gs overall tend to have among the best health on the
planet in terms of freedom from long-term degenerative diseases, it has to
make you think that the obsession with eating a totally raw diet is not as
causative as other factors. (It is appearing the more powerful factors have
to do with avoiding grains, dairy, and eating a macronutrient profile that
allows one to avoid both deficiencies and hyperinsulinism--generally a diet
relatively low in carbs, higher in protein, with the amount of fat not as
critical as its sources. I.e., in particular, avoiding trans-fats
(processed, hydrogenated oils, etc.), and eating adequate fresh
veggies/fruits.)

> Is there any evidence of a species which had initially a diet A, then
> changed for a diet B, and became unable to thrive on the diet A?

I think there is no question that this can occur, given that fish evolved
into amphibians into reptiles into mammals into primates into humans, etc.
A  mammal would likely not thrive too well on the diet of a fish, eh? :-)
So one relevant question here is timespan. Rather than whether it can occur
*in general* (it can), you have to look at specific examples for the
question to be answerable/ relevant. On the other hand, evolution can occur
in spurts, so the question is not one of absolute timescale, but relative
to the degree of evolutionary change over what period of time. On the
timescale of common ape ancestor (5-7 million years ago, perhaps) on
forward to the present, these questions would have more relevance, and even
more relevance from the time of Homo habilis (the first primitive human
forms) about 2 million years ago.

The person who consistently seems to have ruminated at least a little over
these kinds of questions and might be able to give you some kind of answer
is, again, Loren Cordain, Ph.D. (Loren is getting to be sort of a "national
treasure" over on the Paleodiet list--his breadth of knowledge and database
of 15-20,000 references is truly astounding.) If you are really interested
in these questions, I would suggest subscribing to the Paleodiet list,
lurking for awhile and seeing what goes on, then occasionally write private
email to Loren with a question here and there, and ask him to give
references that you can follow up on. (He is usually happy to suggest a
few.) Just don't pepper him with too many questions, and choose your spots
carefully, because he is busy enough as it is. Also, researcher Staffan
Lindeberg from Sweden who has studied the Kitava is very cordial and easy
to talk to.

> ** About the possibility of a need for cooked food: is it plausible/
> possible that humans have lost some ability to process some natural
> toxins? Or to digest some raw foods efficiently?

Again, these are not questions I have really looked into in depth. But
there is one interesting example I know of that might have possible
relevance to the first question: Humans, and I believe some (most?) of the
other primates, have lost the ability to synthesize vitamin C--they must
get it in their foods, while animals in the evolutionary line prior to us
CAN synthesize it. I believe there is info about this on the
talkorigins.org website on the link that talks about pseudogenes.
(Geneticists have traced the loss of the ability to synthesize vitamin C
through either pseudogenes or other types of genes common to primates and
humans.) So there is some precedent for the loss of--in this case not
digestive, but assimilative/synthesizing ability where nutrients from raw
foods are concerned. Aha, I just found the passage on the talkorigins.org
site (URL is: http://talkorigins.org/faqs/molecular-genetics.html, author
Edward Max, M.D.,Ph.D.):

     Guinea pigs and primates, including humans, get sick unless they
     consume ascorbic acid in their diet. For humans and guinea pigs,
     ascorbic acid is thus a vitamin (vitamin C), while most other species
     can synthesize their own ascorbic acid and thus do not require this
     molecule in their diet. The reason humans and guinea pigs cannot
     manufacture their own ascorbic acid is that they lack a functional
     gene encoding the enzyme protein known as L-gulono-gamma-lactone
     oxidase (LGGLO), which is required for synthesizing ascorbic acid and
     which is present in other mammalian species. Since these other mammals
     make functional LGGLO enzymes encoded by functional LGGLO genes, the
     evolutionary hypothesis is that these genes were inherited from a
     LGGLO gene in a common ancestor of mammals, and that the LGGLO genes
     in the human and guinea pig lineages were inactivated by mutations.
     Presumably this occurred separately in guinea pig and primate
     ancestors whose natural diets were so rich in ascorbic acid that the
     absence of LGGLO enzyme activity was not a disadvantage--it did not
     cause selective pressure against the defective gene.

Concerning raw food digestion specifically, Cordain tells me the human gut
has never been all that great at digesting raw starch to begin with, and
has posted some on this on the Paleodiet list, so the example of not being
able to digest raw potatoes very well, for instance, isn't relevant to the
question, since these are raw starch foods, and the ability wasn't there to
begin with in that large a degree.

I personally would surmise that you would have to simply look at a specific
raw food when asking the question. This is because some foods are MORE
digestible raw, or at least more nutritious (higher rate of nutrient
assimilation)--nuts, fruits, and meat--and others LESS digestible and
nutritious when cooked (potatoes, grains, and a number of vegetables). One
cannot always assume that a raw food is more digestible to begin with, or
that the fact we cannot digest it as well raw as cooked means we ever
digested it better raw in the first place. For what it's worth, Cordain
tells me the evidence from food science (which is very scattered and no
unifying review studies have ever done) suggests our digestive abilities
haven't changed much in the last, let's say, 100-200,000 thousand years or
so, though.

> If I give a 50% bread diet to mice for 1000 generations, will the 1001st
> generation need bread to survive?

Again, I don't know. But here is the reasoning process or stage of events
that would determine the eventual answer: Evolutionary principles tell you
that over time, the mice population being fed the bread (hey, it rhymes :-)
) would become better and better adapted to consuming that food. But the
real question is: how much does the new ability come at the expense of old
ones? Generally speaking, since evolutionary adaptation means one's
physiology is changing to become more fine-tuned to what one is forced to
adapt to--and doing so carries an unavoidable "opportunity cost," since the
organism has to put more energy to shift resources to meet the challenges
of the most dominant evolutionary stressor--there would undoubtedly be some
impact on the efficiency of other pre-existing adaptations. In extreme
cases, perhaps their loss. In not so extreme cases, perhaps just a
diminishment in capacity.

In other words, evolution is a system of trade-offs among competing
survival pressures. So the long answer is: You do something long enough and
the species will adapt to it (assuming it survives), and lose other
abilities in the bargain to one degree or another in the bargain, or those
other abilities might "morph" into something else to accommodate (make room
for in metabolic or physiological terms) the new adaptation. Thus you could
say the organism "requires" or needs an environment compatible with its new
adaptive ability. One would suspect that if a creature adapted to a 50%
diet of anything, it would be very likely to need it. For instance humans
have apparently had a 50% meat diet since Homo erectus 1.7 million years
ago. The experience of not-insignificant numbers of vegetarians and vegans
with deficiencies suggests that we do need it.

On the other hand, there was a post on the Paleodiet list, I think,
recently, that said that even animals such as gramnivorous animals (rodents
perhaps?, I am not clear) are not really completely adapted to grains,
because they still exhibit metabolic characteristics that indicate some
detrimental impact showing not-yet-full adaptation.

> ** About the adaptation to seafood: humans have been consuming seafood for
> 20,000 years, which may be not enough for a complete adaptation, but
> humans are much more adapted to fish than to dairy, possibly because fish
> has a composition which is close to other animal foods. Does the argument
> that some humans are allergic to seafood has any validity? It is known,
> for instance, that many people are allergic to pollen. However, pollen has
> certainly been present in human history for quite a long time; it seems
> that people who are on a gluten and dairy-free diet see their allergies
> disappear (suppressing an allergen lowers the threshold for other
> allergens). I wonder if some long-time paleo-eaters are still allergic to
> seafood.

These are all EXACTLY the same questions I have, and no one seems to know
the answers that I have talked to, though I haven't asked Herr Cordain yet,
or tried to get reference pointers from him to follow up. (I try to ration
out my pestering of him.) Also, frankly, it's only recently a year after
the H&B interviews were originally written (which really burned me out the
first time due to the extensive and quite tedious reference-checking that
was necessary) that I am now starting to regain some enthusiasm for these
questions, so even with the updates added to the interviews, I am not as on
top of things just yet. Once I start getting into it again, I may be able
to find out some better answers.

> ** About animal fat: hunter-gatherers typically eat wild game, which is
> low in saturated fat. On the other hand, they prefer the fattiest parts,
> like bone marrow, but let's say that overall the percentage of saturated
> fat is much lower than in domestice animals. Since for us (modern humans)
> it is difficult to have a diet based on wild game, would it be better for
> us to be moderate on farmed land animals, and have the "animal food" part
> consisting mostly of fish, to get those beneficial EPAs? [one of the
> reasons why Eskimos have low cholesterol is that they have a high intake
> of EPAs].

Man, you are asking some great questions. I have some of the same concerns
about whether it would be better to moderate one's consumption of domestic
animals and substitute fish instead. I have seen some recent research on
fats lately on both the Paleodiet list, and in Mary Enig's research that I
think may provide the answers once I can get in the right head-space to
persevere and tackle it. I'll file these questions down for further
investigation, and hopefully be able to get back to you at some point.

--Ward Nicholson <[log in to unmask]

P.S. Due to a recent spate of work that's come in the last few days, I'll
be on deadline for the next week or so--so will not be able to make more
than minimal posts on any follow-up questions to this until I get the work
out the door. Thanks...