Dean Esmay writes: >I had my preconceptions rocked this week. Which is always a healthy thing, >but I'm still reeling from it. > >My assumption has long been that most cereal grains and beans are foreign >to the human digestive tract because they can only be rendered edible by >technology--i.e. extended cooking. Earliest evidence for use of fire for >cooking among humans seems to be 25,000 years (I have no reference for that >handy, let me know if that's in dispute), which would indicate the >potential for some adaptation to cooked foods. From what I know from having combed through the research I have been able to find myself, the evidence for earliest use of fire itself goes back much further than 25,000 years, although it is very difficult to say with any certainty just when cooking practices began as a result of previous familiarity with fire. About controlled use of fire itself, however, even someone as skeptical as Steven James, in a review article of the evidence for early fire use, concedes that by at least 230,000 years ago, at the Terra Amata site in Spain, one finds clear evidence. [James S, 1989, "Hominid use of fire in the lower and middle Pleistocene. A review of the evidence." Current Anthropology, v.30:1-26] (Newer dating techniques may have pushed the date for this site back to 300,000 years, but I am not sure.) However, since this review-of-the-evidence article, there is now other recent evidence at, I believe, another 2 or perhaps 3 sites in Spain and/or France, including one in France (Menez-Dragan) that would push the controlled-fire-use date back to around 380,000 to 465,000 years if the claims stand up to testing. Also of significance is that burnt rhinocerous bones were found close to a hearth inside a cave at this site, leading the researchers to tentatively conclude cooking had occurred, as it seemed unlikely to them the rhinocerous bones could have gotten inside the cave otherwise. [reported by journalist Patel T 1995, "Burnt stones and rhino bones hint at earliest fire." New Scientist, June 17, 1995, p.5] I also believe (and would like to hear informed comment from those here better acquainted with the evidence than I) that while some of the very earliest claims for control of fire by humans (approx. 1.5 million years ago) at Zhoukoudian Cave in China have now been disputed or discredited, more recent analysis of the ash layers in the cave dated to 230,000 to 460,000 years ago, in which animal skulls have been found, show burn patterns around the teeth and skulls that would indicate cooking of the brains [Rowley-Conwy, Peter 1993, "What do the Zhoukoudian finds tell us?" In: Burenhult, Goran (ed.) The First Humans: Human Origins and History to 10,000 B.C. New York: Harper-Collins, p.65. This is a compendium put out by the American Museum of Natural History, and not peer-reviewed, but Rowley-Conwy is a well-known authority in the field, I believe.] One thing I have heard only one writer discussing fire address is what can be inferred about cooking just from the evidence for control of fire itself. Somehow the question of fire use seems to catch the researchers' attention, but the advent of cooking--which seems to be just as much or more interesting a question to me--does not. But if one were going to suppose, doesn't it seem logical to infer--when you consider why hominids would have been interested in controlling fire in the first place (why were they doing it at all?)--that it would have been for either warmth or cooking food, or both? I wonder what others think about that supposition, given that fire does not leave many useful traces behind, at least, according to what I have heard stated in the literature. As is often said, "Absence of evidence is not evidence of absence." Dutch writer Johan Goudsblom, in his 1992 book "Fire and Civilization" [Penguin Books: London; New York] notes that animals in the wild, like birds of prey such as kites, quickly gather around burned-out wildfires to eat the burnt victims, and other animals can be seen gathered round the wildfire-sites later at night, apparently attracted by the warmth. The implication of this leads to the supposition, which I believe was Goudsblom's point in bringing it up, that if other animals take advantage of fire in this way, then it would seem unlikely that observant hominids would not also have followed suit with regard to its use for warmth and possible processing of food fairly early on after first controlled use. (Ann Brower Stahl, however--commenting in the follow-up section to James' Current Anthropology article--believes that fire's use for warmth would have predated its use for cooking.) The most relevant question, though, it seems to me, where Paleodiet is concerned, is when the use of fire for cooking became *widespread* enough that it would have begun to constitute a serious evolutionary selective pressure. On this point, Steven James notes that consistent evidence for fire use itself in a number of different archeological locations is not seen until at least the late Paleolithic, which he defines as roughly (if I am remembering correctly) 125,000 years ago and more recently. However, if it is true that ancient fires would not leave many traces behind archaeologically in most cases, it may be we are faced with a paucity of evidence by the very nature of the question, which leaves us in a dilemma. I don't know, though, what do others think? Where hard evidence is concerned, though (as opposed to inference), there does not seem to be much indication that *widespread* use of fire for cooking goes back more than about 40,000-60,000 years or so, but I would like to hear more input from others more well-versed than I, since I have had trouble even finding much interest, let alone data, in the fire-and-adaptation-to-cooking question in what Paleodiet literature I have been able to unearth myself. >Yet it would seem that the fact that grains and beans are inedible without >>things like cooking pots and mortar and pestle ought to make us look with >>suspicion to those foods, since that all by itself would tend to indicate >that >humans would never have eaten them in any appreciable quantity until >around the >time of agriculture. > >Enter the members of the raw food community who I recently encountered >online. These people eat absolutely everything raw, on the belief that the >molecular changes wrought by cooking foods are unnatural, addicting, and >carcinogenic. I am mildly skeptical of this belief system, although there >is some rational argument for it; humans ARE the only animals who cook food >and most of the evidence I've seen suggests that we haven't been doing it >for very long. I am still reserving judgment myself on the question of whether or to what degree cooking foods may render them "unnatural," addicting, or carcinogenic. (Cooking creates some carcinogens, but neutralizes others; and most plant foods contain a certain level of "nature's pesticides" in the first place as a self-defense tactic to discourage animals from eating them; so the question is not a cut-and-dried one. [See Ames, B 1983, "Dietary carcinogens and anticarcinogens." Science, v.221 (Sept. 23, 1983), pp. 1256-1264]) However, one thing about the raw-foods community that I think should be strongly emphasized, which I point out here based on my own first-hand experience as a former member of the raw-foods community myself, is that the walk does not match up completely to the talk. You will hear lots of claims that someone is eating 100% all-raw foods, but when you get them in private, or cross-examine them in public, most will admit they can't or don't sustain the full regimen. This is not to say that there are not some very notable examples of people who do, because there definitely are (and I know one or two of them on this listgroup). But most avowed "raw-foodists" are actually eating more like 70% to 80%, perhaps 90%, raw foods. Still a lot of raw food, of course, but it seems to me very significant that for the vast majority who try (and most who become convinced it is the ultimate way to eat get pretty motivated about it and try hard) there seems to be some sort of barrier preventing them from taking it all the way. (Also, it is important to note in saying this that most raw-foodists are vegetarians as well, and the lack of animal-food intake could be affecting their ability to otherwise successfully sustain a raw-food regime.) I recently resigned the editorship of a small many-to-many newsletter on health and vegetarian raw foods that I ran for 4 years, due to growing disillusionment with what I saw regarding preaching vs. practice, as well as becoming increasingly familiar with the evolutionary Paleodiet literature. (Many-to-manys work just like on-line listgroups as far as comment-and-response discussions, except they are distributed through snailmail.) Many of the participants were, or claimed to be, or had tried to make a go of, eating all-raw foods. But when their actual practices were flushed out through cross-examination, as near as I could tell, not more than about 10-15% of them were actually successful at walking their talk over the long-term in good health. And of those who had tried to eat all-raw foods but could not sustain it, most gave it up either because of strong cravings they could not satisfy on the all-raw regimen, or because of health problems, or both. There are no scientific studies or surveys of raw-foodists that I know of myself, but I wrote an article last year from the "former insider" perspective about raw-foodists who follow the Natural Hygiene philosophy of natural diet, which strongly emphasizes raw foods, and the problems many of them experience. (If anyone is interested, I can snailmail a xerox of it for $2 (to cover my time and copying/mailing expense) to anyone interested. (The article runs 12,000 words.) Or I might see if I can't get it translated to ASCII here soon instead to email to those who have an interest. >But what really rocked me is that these people (and I've seen messages from >more than one of them) eat whole cereal grains and beans raw. They most >commonly will use overnight soaking methods, either in pots or jars or even >just wrapping the stuff in moist rags. However they will also apparently >eat them even without this, eating them completely raw without even any >soaking. Their claim is that if you haven't been eating this way all your >life it might take a week or two for your digestive tract to adjust, but >that they otherwise have no trouble at all living this way. As a former insider, this is true--at least for those 10-15% who succeed on the type of raw-foodist dietary program that may include such practices (though not necessarily for the other 85-90% who don't succeed too well). It should also be specifically noted in connection with this practice that most people who attempt a raw-food vegetarian diet and fail are usually only able to later succeed on their dietary program by modifying it to include some sort of concentrated starch or protein food. (Most end up including something like steamed or cooked squash, potatoes, legumes, or grains.) However, as Dean says, those who are really serious about continuing to eat only raw foods--but who resort to eating grains or legumes to round out the diet to succeed--will soak or sprout them (for a day or two or less) to be able to ingest them raw. And then there are a very few who, as Dean mentions, will also eat the grains raw without even soaking them. (They may grind them first, of course.) Whether and how much of the grain they are actually digesting when eaten this way is an open question. (Cooking helps neutralize the trypsin inhibitors commonly found in legumes and grains that otherwise interfere with digestion, so it is questionable how much raw grain eaters actually digest and assimilate of it, even if they can tolerate it fine. [I don't know what a trypsin inhibitor is, but Ann Brower Stahl briefly discusses the situation in her 1984 paper, "Hominid dietary selection before fire," Current Anthropology, April 1984, v.25, no.2, pp.151-168.]) But I agree with Dean's inference that Paleodiet researchers really ought to look into this and see what is going on here physiologically with these folks. Regarding the many failures of those attempting a raw-food diet, I have also had conversations with a person well-acquainted with the "instincto" segment of the raw foods community from the inside who I believe is on this list. (Instinctos are raw-foodists who do not limit themselves to vegetarianism and freely include raw meat in their diet.) This individual can comment here themselves if they like, but they have told me that in their estimation the success rate for raw-food instinctos is no better than for the raw-food vegetarian crowd (i.e., 10-15% or less, they thought, from widespread acquaintance). In bringing all this up with a Paleodiet researcher (and again, if they are on this list, I'm sure they will speak up for themselves) who believes humans are not yet genetically much-adapted to cooked foods, it seemed their opinion was the raw-food failures were due to two things. First, since hominid diets have evolved over the eons to include not only much more animal foods than our primate cousins--and these animal foods are in general more concentrated, less fibrous, and more efficiently assimilated foods than plant foods--vegetarian raw-foodists will have a hard time getting a concentrated enough stream of nutrients without including concentrated vegetarian starch foods like grains or cooked tubers, etc. I.e., since every organ system comes at a metabolic cost, and it takes a large gut to digest a diet high in fiber; and since humans have smaller guts than their primate cousins, for which we have compensated by eating more concentrated, more nutrient-rich, less-fibrous animal foods that allowed us to evolve a large metabolically costly brain, many people who attempt a vegetarian diet are going to find they have to eat more food than they can realistically handle-volume wise unless they include more concentrated foods like grains, legumes, and tubers by way of cooking them to make them edible. (And this supposition seems to agree very well with the actual results and practices I have seen in the raw-foods community myself.) Second, the reason the instincto raw-foodists (who include meat) may be having a hard time succeeding, is that it seems from observations of modern hunter/gatherers eating meat that they go for the organ meats first which they value most highly, also even the bone marrow. Muscle meats are eaten last and least valued, yet those of us in the modern age have access to mostly only these muscle meats. So it appears that even most raw-foodists who include animal foods have trouble because they do not eat the best portion of the animal, and may be shorting themselves nutritionally. My question in all this is: If hominids evolved eating nothing but raw foods, and we are not yet adapted to the cooking practices begun relatively late in our evolution (though considerably more ancient than agriculture), why then do so many people fail on raw-food diets, even the ones who eat plenty of meat? Do the above reasons just given make sense to those of you who are researchers? I don't get the feeling from my perusal of the literature that very many Paleodiet researchers have even thought to address the cooking vs. raw-foods survival question, and whether homo is now adapted to a certain amount of cooked foods (or to certain ones customarily cooked during evolution) or not, but I would be interested to hear comments. To me, this consideration also bear on the question of how we might compensate these days for the fact that we cannot obtain organ meats and bone marrow, and whether cooking of certain foods may be a necessary evil to help make up the difference somehow. >At first I was tempted to dismiss this as a bizarre cultish sort of thing. >But if these people apparear to be happy eating this way. Actually, as I've said, most people who try to 100% raw-foods do not succeed at it over the long-term--though they will rave about it during the short-term and be most vocal before they start having problems--and a lot them are not very happy about that fact, or disguise it. However, as you also say... >The very fact >that it's POSSIBLE for them to do this should, at minimum, throw back open >to question whether or not humans have been eating cereal grains since >before the advent of agriculture after all. Although it's hard to imagine >them making up the majority of the diet, if people can comfortably eat wild >grains without technology then there's not much reason to think they >wouldn't, is there? Great question. It *is* possible to eat grains without technology, and some individuals that try it--mostly vegetarians--are able to succeed healthwise at it. However, there is also the well-known fact that apparent success or not, phytates in grains greatly impair mineral absorption which seems to indicate we are not yet very well adapted to them, even if it is possible to eat them. --Ward Nicholson <[log in to unmask]> Wichita, KS