I've been listening to a little bit of the Paleo Summit and today I listened to Nora Gedgauda's presentation on "safe" starches. You can still catch it for another hour or so I think, but let's just say it wasn't my favorite presentation in the world.
If you've read this blog long enough, you know I have an interest in fiber. One thing that is interesting about early "paleo" books, Boyd Eaton's 1989 The Paleolithic Prescription, is that they recommend an absurd amount of fiber. That's partially because some estimates of fiber intake based on fossilized poo, known as coprolites, were just simply absurd, as high as 150 grams a day, which no known human culture even approaches. So I've spent a little time arguing against that, because the coprolite analysis for fiber isn't even very accurate in the first place.
So when I hear more info about coprolites, my ears perk up, particularly if it's totally outside the realm of anything I've ever heard. In Nora's presentation she cites a paper that she says shows that a wide-ranging sample of paleolithic coprolites shows that they weren't eating any plants. What?
So I tracked down this paper. Turns out it's not a paper, it's an article in a magazine, though I admit that Scientific American is definitely a quality magazine.
So your homework assignment for the night is to read the "paper" and figure out where it says any of what Nora says at all
Spoiler: it doesn't say any of those things at all. Nope, none. Hilariously, a lot of the article is in fact devoted to the Pecos basin hunter-gatherers I've written about, but they didn't live in the Paleolithic and they ate a massive amount of various plants.
Bonus point: find ANY paper that supports what Nora says.
Nora is trying to fight Paul Jaminet's mainly bio-chem based arguments about starches with anthropology, but she doesn't have much ammo. The idea that homo sapiens was forged in some kind of arctic ice age goes against all the existing genetic and archeological evidence that exists. When we are talking about the influence of the last ice age on homo sapiens, it's more about forests dying off and becoming grasslands and savannas, than people plunged into some polar darkness in which they could only eat mammoth.
Nora then cites the isotopic evidence. Nope, she doesn't cite one of the many papers on the subject, she cites Dr. Eades, who is an MD, not an anthropologist. Probably because in those papers they try to make it clear that isotope analysis cannot tell us that ancient hominids were eating like foxes. It can simply tell us the trophic level of the protein consumed, which is similar to foxes in SOME cases, but we are not foxes. We are large-brained primates with the ability to eat a vast variety of foods, so the trophic level cannot rule out other foods being consumed, nor can it tell us the amount of protein in the diet. John Hawks put up an assortment of posts on isotopic analysis in response to an email from Chris Masterjohn.
As for the ketogenic babies, I think babies are really the reason that most humans can adapt better to ketosis than most other mammals, which I learned from Stephen Cunnane's excellent book Human Brain Evolution: Influence of Freshwater and Marine Food Resources:
There are two key advantages to having ketone bodies as the main alternative fuel to glucose for the human brain. First, humans normally have signifi cant body fat stores, so there is an abundant supply of fatty acids to make ketones. Second, using ketones to meet part of the brain ’ s energy requirement when food availability is intermittent frees up some glucose for other uses and greatly reduces both the risk of detrimental muscle breakdown during glucose synthesis, as well as compromised function of other cells dependent on glucose, that is, red blood cells. One interesting attribute of ketone uptake by the brain is that it is four to fi ve times faster in newborns and infants than in adults (Robinson and Williamson, 1980 ; Cremer, 1982 ). Hence, in a sense, the efficient use of ketones by the infant brain means that it arguably has a better fuel reserve than the adult brain. Although the role of ketones as a fuel reserve is important, in infants, they are more than just a reserve brain fuel – they are also the main substrate for brain lipid synthesis (see Baby Fat – The Reserve for Brain Lipids section).
I have hypothesized that evolution of a greater capacity to make ketones coevolved with human brain expansion (Cunnane, 2005a ). This increasing capacity was directly linked to evolving fatty acid reserves in body fat stores during fetal and neonatal development . To both expand brain size and increase its sophistication so remarkably would have required a reliable and copious energy supply for a very long period of time, probably at least a million, if not two million, years. Initially, and up to a point, the energy needs of a somewhat larger hominin brain could be met by glucose and short - term glucose reserves such as glycogen and glucose synthesis from amino acids. As hominins slowly began to evolve larger brains after having acquired a more secure and abundant food supply, further brain expansion would have depended on evolving signifi cant fat stores and having reliable and rapid access to the fuel in those fat stores. Fat stores were necessary but were still not suffi cient without a coincident increase in the capacity for ketogenesis. This unique combination of outstanding fuel store in body fat as well as rapid and abundant availability of ketones as a brain fuel that could seamlessly replace glucose was the key fuel reserve for expanding the hominin brain, a reserve that was apparently not available to other land - based mammals, including nonhuman primates.
But I don't think that means it's optimal for adults. If anything, it's possible adult's ability to be in ketosis is a relic from infancy. Perhaps that's why some people seem to do better on ketosis than others, because like lactase persistence, the persistence of that ability varies from person to person. But I don't really know, it's just an idea and unlike some people I don't claim to know what everyone else should eat.
As for the Inuit not eating plants, it's 2012 and I think there is enough information on the internet available, like my own blog posts, that put that misconception to bed.
No, but people take this stuff seriously, as you can see in the comments:
As far as Nora's presentation goes, it's backed up by more science and understanding of human physiology than any of the pro-carb messages I've seen.
If you want to listen to a better talk, I'd suggest Mat Lalonde's. I wish he'd write a book. We know paleo can work, science can help us figure out why and knowing why can help us target variations of the diet to individuals. I firmly believe that a successful diet involves acknowledging the normal distribution and trying to "pin the tail on the donkey" to find your place there (or your range dependent on other variables) through self-experimentation and other tools. It's clear he does that in his own life, so he's talking the talk and walking the walk. I do differ in opinion in that I have tended to think that issues with grains aren't issues with proteins, but issues with carbohydrate malabsorption. But I'm open to both ideas being right.
Most importantly, Mat calls us to be rigorous in our use of scientific evidence, which is something many other speakers at the Paleo Summit seem to be unable to do. Their readers, who do not have access to academic journals by and large, take them seriously without ever knowing the truth.
As for the idea that those of us who are skeptical of the anti-starch stance just being addicts, I really do laugh because I remember a comment a militant vegan relative of mine posted on the blog. He accused me of making up evidence for meat being healthy just because I think it's so tasty. Ha. Anyone who knows me knows that when I started trying "paleo" diets, I did not like meat very much, though I do like it now.
As for starch, the idea that I'd be addicted to the mediocre bland peasant-like tastes of things like cassava or green plantain is absurd. I really challenge anyone who thinks such things are addictive to go to their nearest ethnic market and purchse a true yam. Then boil it and eat it plain. Have fun!
If I promoted a diet based on what I crave, it would be based around caviar, bone marrow, and butter. Through, it is quite funny that all of those things are quite good for you.