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Tuesday, December 27, 2011

Starch is Paleo?

Tsimblist brought this presentation Dr. Nathaniel Dominy to my attention recently. 


Something commonly raised in favor of a high (animal) fat diet in paleolithic humans is the notion that this was required and/or precipitated the increase in human brain size.  He seems to be saying this is not so much the case as is often cited.  (Around the 9 minute mark).  This is a huge point!!  Dominy does not come across as some vegan shill, that's for sure.  He pretty much comes out and says that meat eating is a no-brainer -- we're not herbivores -- but favors a higher percentage of plant foods likely comprising our ancestral diet.  Worth a watch/listen.

14 comments:

Miki said...

Dr. Dominy knows a lot about AMY 1 but rather little about historic diets. Recent hunter gatherers ate meat almost exclusively whenever they could. other groups (not many) ate plenty of starch but they are the exception. If starch was so popular why AMY 1 increased number of copies happened only within the last 200,000 years out of Homo's 2 million years of existence? and still we do not all have multiple pairs. If starch was so prevalent we should all have had plenty of genes for amylase yet we don't.
The Most active recent genetic adaptations are to starch and specific anti nutrients in Underground Storage Organs in populations that consume them (see Hancock AM, Witonsky DB, Ehler E, Alkorta-Aranburu G, Beall C, et al. (2010) Colloquium paper: Human adaptations to diet, subsistence, and ecoregion are due to subtle shifts in allele frequency. Proc Natl Acad Sci U S A 107: 8924-8930.)

Evelyn aka CarbSane said...

Hi Miki, What do you make of the brain size argument? I don't know, I remain of mixed feelings about how far back into the Paleo age do we go? I'm pretty much on the fence over these topics as I've been for a good long time. If we hunted various species to extinction, then the nature of our animal sources changed greatly over time as well. I don't see how modern beef liver and pig hearts compares to the animals that roamed the earth a million years ago.

Thomas said...

"Recent hunter gatherers ate meat almost exclusively whenever they could."

Whenever they could being the key word here. There is no doubt that humans preferred meat as food, I'm sure they were driven to get it just as many or most of us are these days. But just as big game animals had to follow the resources to survive, humans (before animal husbandry) had to follow the big game animals to get significant quantities of meat. As animals tend to know their predators and were constantly on the move, I highly doubt that attaining this meat was simple-likely it was an exhausting and sporadic event. Not to mention population stresses animals experiences when resources didn't pan out, such as with famine or other natural disasters. Having back-up and alternative sources of food, (ie. plants, tubers etc. (equivalent to our mac and cheese and ramen?)), would have been as important to survival as meat. Also, it's hard to argue with the dental record when it comes to selective pressures determined by food availability. It would seem that meat, although a preferred food, just wasn't that available all of the time-not enough for us to evolve a meat eaters mouth anyway.

Rip & Clip said...

"hunter gatherers ate meat almost exclusively whenever they could"

I liek how you worded this, HG's ate almost anything edible exclusivly whenever they could.

vladex said...

What do you make of the brain size argument?
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I'll try to answer it. Brain size is most definitelly related to cooking food, whether it's starch, vegetable or animal origin. Cooking releases energy easily and cuts down costs of digestion which allows more nutrients and energy to be used elsewhere, namely the brain. Cooking also enforces certain preparations which require lots of cognitive activity and also builds dependence within groups and individuals, hence the tribes and marriage arose after the cooking invention.

Jes said...

Evelyn - I have a question not really on-point for today's post. Do you accept messages/email questions? I assume not since I don't see a link, but thought it was worth a try.

Best,

Jessica

Evelyn aka CarbSane said...

Hi Jessica, Yes, as time permits. The discussion boards here aren't really active and part of that is my fault for relying on email notifications that were not set right -- in other words there were some questions that went unanswered b/c I didn't get notice and when posting is slow I don't check daily. In any case, I've fixed that, so one way is to "Ask CarbSane"

If you prefer more private communication, my email is carbsane at gmail dot com. I do try to answer all, but again, life can get busy. I prefer the more public query if only because my responses may answer questions others might have.

:-) Welcome!!

Evelyn aka CarbSane said...

Welcome vladex! (I recognize you from Mercola's site -- wear that Dissenter badge proudly!!) Speaking of cooking, wouldn't that render out some of the fat?

Edward Edmonds said...

I think the idea that we don't have teeth like carnivores and therefore we ate a predominately a plant dominated diet is the wrong argument to use. We are bipedal so we have two free arms and two free hands to manipulate objects with, we also use tools. We can cut our meat off the animal into manageable sized pieces and chew it just fine with our back teeth negating the need for sharp front teeth. If you ever watch a carnivore eat meat it quickly becomes apparent why they need sharp teeth, they don't have hands and tools to cut if off the animal so they need an efficient way to pull/rip it off the animal, sharp teeth fit the bill in their case because they don't have free limbs. There would be no selection pressure for sharp teeth because of our free limbs and tool use. However, the idea that plant material is everywhere and being adapted to eating it would be a significant advantage for us is a good argument.

vladex said...

Welcome vladex! (I recognize you from Mercola's site -- wear that Dissenter badge proudly!!) Speaking of cooking, wouldn't that render out some of the fat?
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Thanks , I am not sure what do you mean by "render out some of the fat"?

If you mean that fat just drips away that may be true somewhat and maybe the reason for people inventing and using pans and plates eventually. However the main advantage of cooking was that cooked food was easier to digest and more palatable which made the guts smaller since the digestion is quick and efficient and gave the energy and nutrients to the brain and maybe muscles as well depending on the enviromental pressures.

Evelyn aka CarbSane said...

Yes, that's what I meant, and pots and such make sense. How far do we go back. When exactly did we stop evolving? The carnivore advocates seem to want to put that to millions of years ago ...

vladex said...

There is controversy as far as when humans started to control fire and started to cook but it was probably a million or two years ago with the introduction of homo erectus. Also then came improvements to the diet such as salting,drying , preserving, spicing and crushing which improved digestability furthermore as well as improvements in hunting and gathering overtime. All of that made possible the enlargements in brain. But also we can't forget the movement which was required for hunting and gathering and then cooking, it's possible in modern times due to the lack of movement that most people are actually devolving and the brain is shrinking along with muscle and hair but more fat and more body hair.

Will said...

There is an alternate hypothesis for brain size that has nothing to do with diet, cooking or otherwise:

http://paleovegan.blogspot.com/2011/11/its-curtains-for-expensive-tissue.html

The short story is that there is no inverse correlation between gut size and brain size in any mammal. In fact, there is no such relation between brain size and any expensive tissue, counter to the predictions of the expensive-tissue hypothesis.

On the other hand, there IS a strong inverse correlation between adipose tissue mass and brain size. The leaner the animal, the larger the brain. Fat tissue is not particularly expensive on its own, but it does increase energy needs for locomotion.

Humans walk upright, which is a more efficient method of travel. This frees up additional energy for the brain without requiring a corresponding reduction in fat mass deposits.

Evelyn aka CarbSane said...

Hi Edward, welcome to the Asylum! Our hands aren't particularly suited to tearing apart flesh either, we don't have claws ... so we're presuming tools would be needed, right? I'm more influenced by our mouth structure being suited to other non-plant gathering though too -- insects, grubs and such.

@Will: I'm not sure if you're new here or not. If you are, welcome! Interesting, thanks!

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