Freedomain Radio

Superoxide dismutase, catalase, peroxiredoxins, thioredoxin, and glutathione systems.

Stephen C:

Califlower tastes gross as it comes. 

True, so that makes it not a food for humans.

Uncephalized:

We have been eating significant quantitites of animal foods of all kinds for at least a million years, and cooking food for at least half that time. 500ky is plenty of time for dietary adaptation.

So why didn't it happen then? Time is not the only factor required for adaptation, there has to be selective pressure and available mutations.

If humans really did adapt to meat, where are these adaptations? Why do people who avoid meat live longer and healthier lives?

Uncephalized:

The standard paleo-diet argument that 10ky is not long enough to adapt to the foods of agriculture is more reasonable, though still far from settled.

The Paleo diet has been substantially discreditted. Paleolithic humans got atherosclerosis, a disease that occurs in herbivores when they consume excessive fats.

Uncephalized:

And of course the notion that we are ill-adapted to modern industrial food seems most reasonable, given that it's only been around for a generation or two depending on the food in question, nowhere near enough time for wholesale physiological adaptation (if industrial food even has enough nutrition in it to BE a viable food for health in the first place).

Why do you keep assuming that adaptation is just a question of time?

Uncephalized:

But the notion that we are essentially similar to our frugivorous ancestors physiologically just doesn't hold up IMO.

Let's cut the opinions and see the data.

Martin Pickford provides compelling data that our incisor/molar dental pattern follows the pattern of our Miocene ancestors, see Martin Pickford, Incisor-molar relationships in chimpanzees and other hominoids: implications for diet and phylogeny, Primates (2005) 46:21-32.

Uncephalized:

Our dentition and digestive tracts really don't look anything like chimps, our closest frugivorous relatives, or gorillas, or closest foliovore cousin--and they shouldn't, given what we know of our history since we split with those lineages.

The other great apes are more derived species, yes they are more evolved than humans which have retained more primitive characteristics. And the other great apes are more adapted to eat meat, humans have 0 adaptations for meat eating, it's the other great apes that have become omnivores, not us. That is what the data of Pickford shows.

Uncephalized:

 We're pretty clearly omnivores who are well-adapted to meat consumption.

So where is the data to support this? Why do people cook and use knives and forks to eat meat? Is that your idea of adaptation?

Uncephalized:

The most convincing argument I have heard for our physiology to date is the expensive tissue hypothesis, which actually supports the idea that meat-eating, and cooking, paved the way for us to be able to shrink our gut, allowing us to pay for our large, expensive brains (it doesn't explain why we needed the big brains in the first place, and I don't think anyone has really nailed that one down yet). If we had never moved to a meat-heavy diet, and learned to cook, we might not be having internet discussions about it today.

These are the myths of some irrational anthropologists, much of which is debunked by Terrence Deacon.

SimonF:

If humans really did adapt to meat, where are these adaptations?

 

The tooth in red (the Canine tooth) is adapted for tearing meat.  Canines are NOT adapted for eating fruit, becasue no other non-meat eater has canine teeth.  Canine teeth are the exclusive adaptation of animals that eat meat. 

 

 

Glad to clear that up.

SimonF:

Stephen C:

Califlower tastes gross as it comes. 

True, so that makes it not a food for humans.

According to Simon F, I think.

SimonF:

Uncephalized:

We have been eating significant quantitites of animal foods of all kinds for at least a million years, and cooking food for at least half that time. 500ky is plenty of time for dietary adaptation.

So why didn't it happen then? Time is not the only factor required for adaptation, there has to be selective pressure and available mutations.

Um... it did? Our guts shrank relative to body size, and our teeth and jaws shrank considerably.  Both of these are likely adaptations to cooking our food, which makes it more digestible and easily chewed. Our colons and ceca are much smaller than our relatives as well because we don't rely nutritionally on fermentation of greens for our caloric needs. Granted these examples are not support for carnivory, just that we have derived traits that are likely due to fire and cooking and are not foliovores (which should be blindingly obvious of course from what we see when people try to live on greens alone--they waste away).

SimonF:

If humans really did adapt to meat, where are these adaptations? Why do people who avoid meat live longer and healthier lives?

They don't, if you adjust for all the other confounding factors that typically go along with meat eating vs vegetarianism in Western diets. Tobacco use, smoking, and sedentarism are all more prevalent among Western meat-eaters than they are among vegetarians because vegetarianism is perceived as a "health" practice, and also as unpleasant--so vegetarians tend to be pre-selected for health consciousness.

You are probably familiar with the Seventh-day Adventists study? They are vegetarians and have one of the longest life spans of any group studied (of course they also have serious confounders like an insular community, strong family ties, very low drug and alcohol use, etc.). But guess what? Certain Mormon communities share many of these characteristics, with one key difference: they are not prohibited from eating meat, and tend to eat it regularly. And they live even longer than the JWs do.

You are probably familiar with the China Study if you're advancing the veg*an argument, so I'd be interested to know if you've read these critiques.

SimonF:

Uncephalized:

The standard paleo-diet argument that 10ky is not long enough to adapt to the foods of agriculture is more reasonable, though still far from settled.

The Paleo diet has been substantially discreditted. Paleolithic humans got atherosclerosis, a disease that occurs in herbivores when they consume excessive fats.

I'm not sure how you can make that assertion when I am not aware that we have any soft-tissue remains of any Paleolithic humans at all. If I am wrong please share, I'd love to read about it. Veg*ans, even life-long veg*ans, are far from heart-disease free in modern times, however, so I fail to see how this supports veg*anism specifically.

SimonF:

Uncephalized:

And of course the notion that we are ill-adapted to modern industrial food seems most reasonable, given that it's only been around for a generation or two depending on the food in question, nowhere near enough time for wholesale physiological adaptation (if industrial food even has enough nutrition in it to BE a viable food for health in the first place).

Why do you keep assuming that adaptation is just a question of time?

I don't. Merely that time is a necessary condition for adaptation. I am aware that a selective pressure is also necessary; I assumed it went without saying that if, as you are claiming, eating meat causes heart disease and early death, that would represent a significant-enough selective pressure to cause some adaptation over the course of 500k-1M years. My mistake for not clarifying.

SimonF:

Uncephalized:

But the notion that we are essentially similar to our frugivorous ancestors physiologically just doesn't hold up IMO.

Let's cut the opinions and see the data.

Martin Pickford provides compelling data that our incisor/molar dental pattern follows the pattern of our Miocene ancestors, see Martin Pickford, Incisor-molar relationships in chimpanzees and other hominoids: implications for diet and phylogeny, Primates (2005) 46:21-32.

Is the whole text of that paper available anywhere? I'd like to read it if it's available free; the abstract was interesting.

SimonF:

Uncephalized:

Our dentition and digestive tracts really don't look anything like chimps, our closest frugivorous relatives, or gorillas, or closest foliovore cousin--and they shouldn't, given what we know of our history since we split with those lineages.

The other great apes are more derived species, yes they are more evolved than humans which have retained more primitive characteristics. And the other great apes are more adapted to eat meat, humans have 0 adaptations for meat eating, it's the other great apes that have become omnivores, not us. That is what the data of Pickford shows.

Humans have very generalized and miniaturized teeth. It's consistent with eating cooked foods of all kinds, plant and animal, which is what you see in literally every free-living hunter-gatherer society on the planet (except marginal cases like the Inuit, who don't have plant matter available to them and traditionally eat a diet composed mostly of animal fat by calories--and who were, by all accounts, largely free of disease with a long natural life span until they abandoned their traditional diets for Western convenience foods).

SimonF:

Uncephalized:

 We're pretty clearly omnivores who are well-adapted to meat consumption.

So where is the data to support this? Why do people cook and use knives and forks to eat meat? Is that your idea of adaptation?

We cook, and use utensils to eat, most of the food we eat besides fruit, which is pre-packaged by plants because it is intended to be eaten. I fail to see how this is an argument against carnivory in particular. Of course this is an adaptation. Are you serious? It's a behavioral adaptation that allows us to get away with small teeth, small muscles, small bones, and small guts. Fire/tool use is one of the most important behavioral adaptations in the history of life. We are well-adapted to meat consumption digestively/metabolically--our metabolism utilizes animal tissue for fuel and protein readily.

SimonF:

Uncephalized:

The most convincing argument I have heard for our physiology to date is the expensive tissue hypothesis, which actually supports the idea that meat-eating, and cooking, paved the way for us to be able to shrink our gut, allowing us to pay for our large, expensive brains (it doesn't explain why we needed the big brains in the first place, and I don't think anyone has really nailed that one down yet). If we had never moved to a meat-heavy diet, and learned to cook, we might not be having internet discussions about it today.

These are the myths of some irrational anthropologists, much of which is debunked by Terrence Deacon.

Very convincing one-line answer. Care to give even the briefest of summaries of a hypothesis you find more convincing, that I might be able to learn more about?

Uncephalized:

Um... it did? Our guts shrank relative to body size, and our teeth and jaws shrank considerably.

Stories.

Uncephalized:

  Both of these are likely adaptations to cooking our food, which makes it more digestible and easily chewed. Our colons and ceca are much smaller than our relatives as well because we don't rely nutritionally on fermentation of greens for our caloric needs. Granted these examples are not support for carnivory

Yet more stories and no data to support meat eating.

It's easy to establish to which diet an animal is adapted by feeding it to the animal. Humans fed exlcusively on cooked food do not thrive. Humans fed on raw fruits and some greens thrive. I lived this way for years, so have many others. Some day perhaps science will spend more time exploring this phenomena (i.e. being healthy). But for now I am happy to be one of those in the know and beyond a need to read fictional accounts about what humans might be adapted to and how we may of evolved.

Uncephalized:

They don't, if you adjust for all the other confounding factors that typically go along with meat eating vs vegetarianism in Western diets. Tobacco use, smoking, and sedentarism are all more prevalent among Western meat-eaters than they are among vegetarians because vegetarianism is perceived as a "health" practice, and also as unpleasant--so vegetarians tend to be pre-selected for health consciousness.

You are probably familiar with the Seventh-day Adventists study? They are vegetarians and have one of the longest life spans of any group studied (of course they also have serious confounders like an insular community, strong family ties, very low drug and alcohol use, etc.).

The point with the SDA data is that it compares like with like accept for the variable under study, meat eating. That is why the SDA data is compelling, they provide their own control group. Most vegetarian data is confounded by multiple variables in lifestyle. The SDA data is not.

Uncephalized:

But guess what? Certain Mormon communities share many of these characteristics, with one key difference: they are not prohibited from eating meat, and tend to eat it regularly. And they live even longer than the JWs do.

JWs? Genetics play a bigger part in longevity than diet, that is why you can find smokers who still outlive the average vegetarian adventists. Also Mormons are mainly white whereas SDAs are a significantly black group, and race plays a part in longevity to, so I reject the comparison you suggest.

Uncephalized:

You are probably familiar with the China Study if you're advancing the veg*an argument, so I'd be interested to know if you've read these critiques.

Yes, I have read D Mingers articles, she has her critics too (google them, and see below), but unlike Minger they understand statistics.

http://www.youtube.com/watch?v=zeBmbJzKpt8

http://www.youtube.com/watch?v=2E8CJk3P2-Q

Uncephalized:

I am aware that a selective pressure is also necessary; I assumed it went without saying that if, as you are claiming, eating meat causes heart disease and early death, that would represent a significant-enough selective pressure to cause some adaptation over the course of 500k-1M years. My mistake for not clarifying.

Death from meat eating occurs well after the reproductive years, it does not provide such a selective pressure.

But the key point is that herbivores get cardiovascular disease and meat eating species do not (see below). 

Uncephalized:

Is the whole text of that paper available anywhere? I'd like to read it if it's available free; the abstract was interesting.

You can either buy it like I did, or if you are lucky beg a copy from the author. Research is expensive and time consuming, one has to actually obtain quality text books and papers and then read them and put the picture together.

Here are some quotes:

"Extant and fossil humans possess lower incisors that are similar to those of most Miocene apes, and their incisor-molar relation is close to that of Miocene apes."

"It is interesting to note that the more carnivorous common chimpanzee (Pan troglodytes) has the most elongated and most procumbent incisive cutting edge of all known hominoids, whether extant or fossil, and the pygmy chimpanzee which seldom eats meat has less"

"The question naturally arises about the function of enlarged and spatuliform lower incisors with permanently sharp cutting edges that occur in chimpanzees. If frugivory is not the complete answer, then what are chimpanzees consuming that requires a long, sharp cutting incisive edge? A possible answer is meat."

"It has been said on many occasions that the enlarged incisor battery of chimpanzees is functionally related to their frugivorous diet (Pilbeam 1969). However, a moment’s thought will show that this hypothesis is incomplete, because there is good reason to consider that most of the Miocene apes were frugivores, as are most extant apes, yet not a single one of them possesses enlarged spatulate procumbent lower incisors such as those present in chimpanzees. There is thus no correlation between frugivory in hominoids and the presence of enlarged spatulate procumbent lower incisors."

"Observations on meat-eating in chimpanzees reveal that they use their incisors a great deal, especially to rip and tear skin from the cadaver."

"The molars of chimpanzees appear to show some features that could be related to meat consumption."

"In summary, not only do chimpanzee canines show features that enhance prey procurement, but also their incisors possess features that increase the efficiency of meat ingestion, and their molars have morphology that increases the efficiency of meat chewing. The canines are frequently used to kill prey, the incisors function as carnassials, albeit poorly when compared to the carnassials of most carnivores, and the molars are employed in chewing the flesh before it is swallowed."

"It seems probable that hominids only started to include meat in their diet on a regular basis once they could prepare it by cutting it into small pieces while it was still outside the mouth. This extra-oral meat preparation was possible only after sharp-edged tools had been invented, from which it follows that regular meat-eating among hominids may have started as late as the Upper Pliocene. Naturally, if sharp-edged tools are found earlier that 2.6–3 Mya, then this would push back the date of the onset of meat consumption by early hominids. Furthermore, meat consumption in extant humans is overwhelmingly accompanied by cooking. Unlike chimpanzees, humans do not generally obtain much nutritional benefit from eating raw meat (Wrangham 2002)."

Uncephalized:

Humans have very generalized and miniaturized teeth.

The dental pattern is common to frugivores, see above. Try eating fruit, our teeth excell at it. Further it is not enough to assume that our reduced dental features are a (genetic) adaptation, when they could just be developmental abnormalities.

Uncephalized:

It's consistent with eating cooked foods of all kinds

Dental problems occur in people who eat too much cooked food, we are evidently not well adapted to it.

Uncephalized:

, plant and animal, which is what you see in literally every free-living hunter-gatherer society on the planet (except marginal cases like the Inuit, who don't have plant matter available to them and traditionally eat a diet composed mostly of animal fat by calories--and who were, by all accounts, largely free of disease with a long natural life span until they abandoned their traditional diets for Western convenience foods).

Free of disease, I'd like to see that data.

Uncephalized:

behavioral adaptation

Is building aeroplanes a "behavioural adaptation" to fly? Come on, there's something very wrong with this idea. Software and hardware are 2 very different things.

If I am going to eat a lot of meat or cooked food, I want to know that I have the hardware for it, not just that I can learn to do it!

Uncephalized:

that allows us to get away with small teeth, small muscles, small bones, and small guts. Fire/tool use is one of the most important behavioral adaptations in the history of life. We are well-adapted to meat consumption digestively/metabolically--our metabolism utilizes animal tissue for fuel and protein readily.

Can you explain these observations:

1) From Harpers Biochemcistry, 4th Ed.: "The rabbit, pig, monkey and humans are species in which atherosclerosis can be induced by feeding cholesterol. The rat, dog, and cat are resistant."

2) "Diets rich in palmitate inhibit the conversion of cholesterol to bile acids." [Meat is a rich source of palmitate.]

3) According to Lucas humans chew at a rate of 1.3 per second. In contrast pigs and dogs (real omnivores), chew at a rate of 3.03 and 3.16 per second respectively, whereas mountain goats chew at a rate of 1.28 per second

Uncephalized:

Care to give even the briefest of summaries of a hypothesis you find more convincing, that I might be able to learn more about?

From "The Symbolic Species". Humans are desomatized, we have a small body not a large head. Our head and thus brain grows at just the same rate as say a pig or cow.

What humans have acheived by cooking is to make indigestable vegetables softer and more digetsable like fruit. This is not adaptation, it is making the best of an ecological catastrophe to survive.

Some 400yo Innuit mummies were found, they ate the traditional "Paleo" diet and they had atherosclerosis. Another Paleo failure. http://www.youtube.com/watch?v=x6j75BDq6DQ

 

I don't need any more data to support that humans eat meat other than going to an event where a grill is involved.

SimonF:

 

What humans have acheived by cooking is to make indigestable vegetables softer and more digetsable like fruit. This is not adaptation, it is making the best of an ecological catastrophe to survive.

 

Isn't making the best out of a non-ideal situation the very function of adaptation?

nvgasso:

Isn't making the best out of a non-ideal situation the very function of adaptation?

Biology online defines adaptation as:

"The adjustment or changes in behavior, physiology, and structure of an organism to become more suited to an environment."

Cooking and eating meat is an example of technology used in order to overcome lack of physiological adaptations. Technology is about applying changes to the environment, it is not about changes to the organism.

SimonF:

nvgasso:

Isn't making the best out of a non-ideal situation the very function of adaptation?

Biology online defines adaptation as:

"The adjustment or changes in behavior, physiology, and structure of an organism to become more suited to an environment."

Cooking and eating meat is an example of technology used in order to overcome lack of physiological adaptations. Technology is about applying changes to the environment, it is not about changes to the organism.

Humans process animal protein even if it's raw (sushi anyone?).  Cooking's primary purpose is to kill any bacteria that my try to take to the meat (even bacteria knows how good meat is lol).  Flavor is also another reason, but not as important.

Cooking also makes the potato easier to digest, but noone is going around saying the potato is not a natural food becasue you have to cook it.  These statments only seem to come from people who are genrally anti-meat.

"The adjustment or changes in behavior, physiology, and structure of an organism to become more suited to an environment."

 

Help me to understand how the use of a knife and a fork is not adaptive behavior, if you can. Here's something to illustrate the point.

I joined a community garden today!  **thumbs up**  It costs $10/season.  We work on the garden Tuesdays and Saturdays.  You come in, you work an hour, you go home with what ever was harvested that day.  Note: they harvest every work day.  What ever is left over goes to the local food bank for the poor.

We have a garden in our back yard, but we don't get a tremendous yeild, not like we got today at the community garden.  This is probably because A) we don't have a very big garden, and B) we're not very good at gardening.  These people really seem to know what they're doing.  You show up, they tell you what work needs done, you go home with food.  Now it's only the first day, so we'll see how it goes, but so far so good!  I can tell you that there is no way we'd get this much food twice a week from our own garden with an hour of labor twice a week, and we certainly wouldn't get anywhere near the variety we're getting.

This seems like a good idea on so many levels:

A)  More nutrious, organic food for my family
B)  Quality time spent together as a family (my wife and daughter came with)
C)  Learning good skills from other more accomplished gardeners
D)  Teaching our daughter good skills and healthy life style choices
E)  Excersize, physical activity
F)  Time out doors, which imo is good both physically (a little sun to help with Vitamin D creation), and spiritually (in a non-religious way)
G)  Good for the environment
H)  Making connections with other like minded people in the community

I'm sure there are more pros that I'm not even thinking about.

We also have a CSA membership which brings us lots of good local, fresh, organic plants and meats.  Between the CSA, the community garden, and our own garden, the amount of foods consumed from the grocery store is becoming less and less.  :)

I)  philanthropy
J)  modeling philanthropy for my daughter

(For some reason the site is not allowing me to edit my last post and add in the above.)

TenguNation:

The tooth in red (the Canine tooth) is adapted for tearing meat.  Canines are NOT adapted for eating fruit, becasue no other non-meat eater has canine teeth.  Canine teeth are the exclusive adaptation of animals that eat meat. 

Glad to clear that up.

Incorrect. According to The Chosen Species (Arsuaga et al.), humans have incisiform canines (incisor like canines) as found in herbivores like deer, and frugivores like marmosets. 

Chimps are adapted to eat meat*, we might have their dental anatomy if we had evolved through a significantly similar omnivorous dietary history, but we didn't.

Humans preserve the original dental pattern of their miocene ancestors that were thought to be frugivores*. That's why it's easy for us to bite into an apple while biting into cow hide achieves very little.

* see: Martin Pickford, Incisor-molar relationships in chimpanzees and other hominoids: implications for diet and phylogeny, Primates (2005) 46:21-32