From: S C [log in to unmask]

>> [The idea that polysaccharides are no paleo] is simply not believable. We
secrete alpha-amylase in our saliva, the sole purpose of which is to initiate
the digestion of
starch.

>Most modern humans also produce lactase, but that doesn't mean that cow's
milk is paleo.  Apparently evolution is fast enough that humans can start
producing enzymes for new foods over a period of 8000 years.

I think you will find that the amylase is present in the saliva of all primates.  Lactase production in adults is, of course, the retention of a juvenile characteristic.  This explanation does not work for amylase.

> You would be hard pressed to find any modern
hunter-gatherers who do not make substantial use of root
vegetables, rhizomes, or tubers.

I think that root vegetables and rhizomes differ from starchy tubers in the
amount and type of  carbohydrate the contain.  I can't be sure about every
vegetable out there, but I know that beets for one contain sucrose--a
disaccharide.  That's easier to digest than starch (amylose or amylopectin).
Also, roots tend to be much lower in carbohydrates than starchy tubers.

As a general thing, I agree.  I'm not arguing for a high-carb diet, but I am arguing that using starch sources such as tubers as part of a moderate or lowcarb diet is perfectly paleo.

> It's true that Cordain offers no paleo-based justification for this, or for
many of his other pronouncements.  This is what bothered me most about his
book.  But I think there is some evidence that our ancestors didn't eat a lot
of starch.

I agree.  But "a lot" is rather vague.  If, for example, one is getting, say 50-150g of carbohydrate per day, and half of that is coming from paleo starches, that's not an amount to overwhelm the system.

> Our bodies don't well tolerate a very high carbohydrate diet. All kinds of
problems follow from this--rampant bowel disease (this is a very widespread
problem), insulin resistance, etc., etc.  This tends to suggest that we
evolved on a diet that was moderate in carbohydrates (that is to say, much
lower than the standard American diet), and this is the opinion of most paleo
nutritionists.

Again, I agree.  But that kind of a diet need not exclude starch sources such as root veggies, tubers, squashes, etc.  Like Richard Geller, I have found that the system that works best for me is a paleo version of the Carbohydrate Addict's Diet: Very little carbohydrate with breakfast and lunch (perhaps 5-15g each), but a liberal amount at dinner, preferably in the form of polysaccharides.  Last night, for example, I had pork tenderloin with a generous portion of acorn squash -- about 2 cups, which comes to about 30g of carbohydrate.  If I don't do this, I find that I experience cravings early in the evening and I'm likely to overeat.  Like Richard, I find that fruit and berries don't do the trick at this meal.

> Starchy tubers and grains are the main source of polysaccharides in the
modern diet, and they are also almost pure carbohydrate.  If these foods were
as widely available in paleo times as they are today, then the paleo diet
would have been much higher in carbohydrates than it apparently was.

If Cordain's estimates are even close, then about 30% of calories as carbs would have been typical (He estimates the range as 22-40%).  In a 2000 kcal diet, this would come to 600 kcal, or about 150g/day.  While this is far less carbs than what most modern people eat, it is still enough to allow for the use of sweet potatoes, turnips, squashes, and other paleo starches.  If I had to guess, I'd bet that the bowel problems are caused by damage to the bowel caused by grain lectins, compromising the ability to deal with what would have been a normal starch load.

> Many starchy tubers also need
cooking to be edible, which is another point against them.

Some need cooking; most don't.  Some are made more digestible just by being pounded, which helps to break the cellulose chambers that hold the starches.
Stone tools would be fine for this.

Todd Moody
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