Just a quickie to point you to a great "tell it like it is" article at the Huffington post. Link below:
http://www.huffingtonpost.com/justin-stoneman/post_868_b_720398.html
The short version: before taking "expert" advice, check their shoes . . . and their motivations. I'll repeat it again: the only person who truly has your best interests at heart is YOU. Everyone else has some other axe to grind. Once in awhile you might luck out and find an "expert" whose goals are aligned with yours, but don't hold your breath.
Monday, September 27, 2010
Saturday, September 4, 2010
Of Mice and Men, Meat and Wheat
Last week, I saw a very interesting show on the Science Channel (or one of the Discovery family), called "How Food Made Us Human". I don't see any more showings coming up, but recommend you keep an eye out, definitely worth watching. Much of the material will be review for those who follow recent ideas on metabolism and evolution, but it was well done: easy to follow, concise, with some nice hands-on demonstrations of the concepts. One I like in particular was the "chewing machine". Some scientists rigged up a gizmo the simulate chewing, and then put in "teeth" taken from casts of Australopithecus and (I think) Homo habilis fossil jaws. Australopithecus has flat teeth, hypothesized to be better for grinding tough fibrous vegetation, while Homo habilis' teeth are smaller with more ridges, better for tearing. And this is exactly what was demonstrated: the Australopithecus jaws made short work of a carrot in a single bite, but barely put a dent in a piece of raw meat. Homo habilis nearly cut the meat in half with a single bite.
In another fun experiment, several human subjects were "locked up" at a zoo, and fed something like the diet of our closest primate relatives (chimps and gorillas), consisting of raw fruits and vegetables. It was mostly vegetables, if I remember correctly, lots of clips of people gnawing on carrots, raw broccoli, and the like. Long story short, everybody hated it. They spent about half the day doing nothing but chewing, and were starving nonetheless. I believe the average weight loss quoted was something like 10 pounds in two weeks (I meant to watch the show again and take notes, but this is the first "free" time I've gotten, and it's only because I'm at the park with the kids). Subjects apparently spoke of the desire for meat quite a bit (when they weren't bitching about all of the chewing and frequent bathroom visits). It's a fun experiment you can try at home yourself!
One part of the show which rather surprised me: one of the scientists visited a remote tribe in Africa who were still living a fairly primal hunter-gatherer existence. What struck me was that these people looked like crap, nothing like the sort of pictures taken by Weston A. Price, or the fossilized H. habilis jaws shown in the chewing experiment. Their faces showed signs of nutritional stress, with small jaws and crowded teeth. One hint here may be the effort they went through to get meat. In the show, they had a porcupine cornered in its burrow (BTW, this thing was huge, the size of a really big dog). The tribesmen spent the better part of the day digging 6-foot deep holes, until they forced the porcupine into the Hobson's choice of which hole to get speared in. It was a tremendous amount of effort to get some meat, and one of the hunters basically said "porcupine sucks, but at least it's meat". They also discussed how socially important it was for hunters to bring back meat, that it brought them status in the tribe, etc. Clearly, meat is at the top of the menu for these people. Yet that they would go to such lengths to obtain it (particularly when they find porcupine distasteful) makes me wonder if hunting isn't so good in this region anymore. Perhaps game has become scarce, hence the appearance of nutritional stress? Yet they're hanging in there, if nothing else a testament to the tremendous adaptability of humanity, made possible by our big brains (and what do you suppose made those big brains possible?)
Anyway, "How Food Made Us Human" has spawned a couple of trains of thought, which I want to share with you here. The first has to do with a mouse experiment demonstrated on the show; the second with the correlations between diet changes and physiological changes over the course of evolution.
The mouse experiment was very interesting, intended to show the effect of cooking on caloric bioavailability. Take some mice, feed them raw sweet potatoes, and measure the change in body mass as well as activity (based on distance run on the exercise wheel). Now cook the sweet potato and do the same thing. If you're still stuck in the calories-in calories-out (CICO) paradigm, the results should spawn massive cognitive dissonance. The mice who ate the cooked food showed the following differences when compared to those eating the raw food:
Of course this all makes perfect sense when considered from the standpoint of evolution and metabolic regulation. Cooking makes calories more available. Though they didn't explicitly say so in the show, one presumes that the quantity of potato was held constant between the two groups (since not doing so would void the entire point of the experiment). So the only difference (presumably) was raw vs. cooked. Mice didn't evolve eating cooked food. The higher caloric availability likely "fooled" their digestive systems into taking up calories too rapidly, faster than required to support normal metabolic operations. Rate of digestion is regulated by hormonal and nervous feedback mechanisms: when the brain and other internal sensory systems think there's enough energy around, gastrointestinal motility decreases, slowing the rate at which food leaves the stomach to be digested and absorbed in the small intestine; and of course when an energy deficit is detected, food moves more rapidly out of the stomach. When the stomach is empty AND your body senses an energy deficit, you get hungry, and are driven to find more food.
That's how it supposed to work. Like all feedback control systems, if you push outside the "designed" range of stability, it starts failing. I expect this to be particularly the case with biological systems. Biological responses tend to follow "S-curve" shapes. There's nothing deep about this. It simply reflects the fact that biological responses are limited by available resources. At some point you run out of the capacity to make more hormones, neurotransmitters, receptors, etc. Insulin response is a great example. As a function of blood glucose, the secretion of insulin follows a shape much like that seen on the Wikipedia page. At some point you either saturate the ability to detect glucose, or saturate the ability of the pancreas to crank out insulin, or both. The point is that it is possible to exceed your body's ability to effectively control blood sugar levels via the action of insulin, simply by changing the effective "sugar density" of the food you consume.
Back to our mice: when faced with an excess of calories, how can the mouse's body respond? It can either store energy, or burn it off (or both). We know some of it got stored, as the mice got heavier. The show gave one example of "burning it off", in the spontaneous increase in activity. I don't know if they measured it, but I'd wager that the mice also gave off more heat, which I think is a more effective way dumping energy. Muscles are remarkably efficient, and it is surprising how much mechanical work you can get out of a kilocalorie, when compared to the equivalent thermal energy (1 kilocalorie will raise 1 kilogram of water only 1 degree C in temperature, but raise a 1 kg mass over 400 meters against gravity). So the outcome of the mouse experiment is wildly inconsistent with the CICO paradigm, but precisely what one might predict from evolution and metabolic regulation. It would be very interesting to see what would happen if the mice were allowed to continue eating cooked sweet potatoes for a longer time period. I wonder if they would develop mouse metabolic syndrome?
The second line of thought follows the main line of reasoning from the show, which is thus: by incorporating more nutrient dense foods into their diets, our hominid ancestors set in path a major evolutionary shift, where gut size was exchanged for brain size. The argument is elegant: if you eat food with greater bioavailable caloric density, you can spend less energy on digestion. That opens up an evolutionary pathway to increase brain size and energy expenditure at the expense of the gut, because you can extract the same energy from food with a smaller and less-demanding digestive system. And indeed, the fossil record seems to indicate that the major jumps in hominid brain sizes came at two critical nutritional junctures. The first was around the time we started eating meat. The second was when we started cooking food, and cooking is hypothesized to have led to modern humans.
It's interesting to consider the evolutionary advantage brought about by our big brains. What advantage did they bring our hominid ancestors? The scientist visiting the African hunter-gatherers went on a bit about how hunting is a fairly complex behavior, particularly as practiced by humans. But there's a lot more to it than that. The brain remembers - it stores information. And an "advanced" brain not only remembers information, but can extrapolate it to the future, making choices now that create advantages later. For instance, it's good to know that when the rains come, wildebeest are going to show up and a certain place, and that there's an effective method for cutting one out of the herd, how to make the tools you need to kill and butcher it, which parts are good to eat, etc. In the context of hunting and gathering, there's a positive feedback loop between the increase in nutrient density and encephalization, each reinforcing the other.
Of course, there's been another major shift in nutrient density since the advent of cooking: agriculture. The advent of agriculture is an interesting case. At first blush it doesn't seem so hot. The main thrust of human agriculture has been domestication of annual grasses for their seeds, i.e. grains. Across the world, in geographically separate locations, populations growing different crops (wheat, corn, rice) uniformly appear to show significant increases in the chronic "diseases of civilization". But evolution doesn't care if your teeth fall out or you drop dead from cancer at age 40. All evolution cares about is reproductive fitness, and agricultural humans had an undeniable reproductive advantage over hunter-gatherers; otherwise we wouldn't be having this conversation.
We had a hint from the mouse experiment above that an increase in dietary effective energy density could lead to "metabolic overload", exceeding the body's ability to balance and regulate the intake and expenditure of energy. And indeed, the evidence continues to mount that a good chunk of our modern epidemic of chronic diseases may be attributable to such metabolic malfunction. It makes me wonder what happened to our Australopithecus ancestors when they started eating meat: did they suffer metabolic disease as well? It's an academic question, of course, as chronic disease or no, meat-eating proved to increase reproductive success. We might ask a similar question about what occurred as cooking gained popularity. These are hard questions to answer from the fossil record. Agriculture happened much more recently, and further is amenable to archaeology (agriculturists tend to gather in large numbers in one spot, as opposed to wandering all over the place looking for food).
But here's a thought: we noted above that big brains are useful for remembering lots of stuff. This is important when living as a hunter-gatherer, because the dynamics of nature are complex. Maximizing reproductive potential in this context means being able to remember and extrapolate the myriad (and often subtle) cause-and-effect relationships of the natural world, along with whatever technological innovations are required to take advantage of this knowledge. This information does not get passed on genetically, but rather through communication, i.e. parents teaching children. Knowledge is power, in a very tangible sense, when talking about hunter-gatherer survival. Greater knowledge implies greater ability to obtain nutrient-dense food, hence greater reproductive fitness; it also means that it takes longer to get that knowledge into the brains of your offspring. It is often argued that diseases of civilization have little effect on evolution, because they generally kill you after the reproductive years. But that assumes the only information being passed along is genetic. If memories are also required for the reproductive success of your offspring, it pays to live long enough to pass along that information. And if you follow this line of reasoning, it's clear there's a volume of information at which the parent will not be able to effectively communicate the body of knowledge while still performing hunting and gathering activities required for survival. Enter Grandma and Grandpa. If the information volume for reproductive effectiveness is sufficiently large, it pays to live long enough to pass along that information to your offspring, their offspring, and so forth. Correspondingly, adoption of new dietary practices must either preserve this longevity, OR require less information to be effective.
So where does agriculture fit in? Is the adoption of agriculture, which brings with it ever-increasing energy density in food, driving us toward the next phase of "big brain" evolution? Good question - but consider this: how much do you need to know to be an effective agriculturist? I would argue rather little, compared to hunting and gathering. A hunter-gatherer may have thousands of foods in their diet, and they have to know where and when to find them, how to prepare them, etc. Agriculturists have relatively narrow diets, and there's a relatively simple and fixed pattern to the whole business: plow the land, plant the seeds, keep out the weeds, harvest. Lather, rinse, repeat. So I think you can argue that agriculture has a much smaller information burden than hunting/gathering. The tremendous technological increases since the advent of agriculture are a testament to how relatively little brain-power is needed for obtaining food anymore, as we apparently had plenty of spare brain capacity to monkey around with things not directly related to getting fed.
Now it is well known that brain volume decreased dramatically with the advent of agriculture. So did adult lifespan. Yet the agriculturists clearly laid the smack-down on the hunter gatherers, evolutionarily speaking. So neither long-term health nor brain size is a reproductive advantage once you start growing your own food (or at least the foods that our ancestors chose to cultivate). There's no point in fueling a big brain if you've got nothing to put in it. And there's no point in keeping old people around if they are not able to contribute directly to the reproductive fitness of their offspring. If you can't work the fields, don't make babies, and we don't need your accumulated wisdom, then you're pretty much just eating food better used for making more genetic copies. So for an agriculturist, dropping dead at 35 may actually have been an advantage.
It makes me wonder what direction agriculture (and more recently, industrial food processing) is driving our "humanness". Does the ever-growing energy density and general availability of food imply we'll evolve even smaller guts and bigger brains? I'll put my money on "No". After all, look around you: it's not like the smartest people are the most successful reproductively. You can damn near be vegetative, contribute nothing to society at all, yet we will ensure you've got all the Big Macs and Twinkies you can stuff in your face to fuel the generation of lots of babies to do the same thing. In our current environment, evolution favors being chronically ill and stupid. It doesn't really matter how much we wring our hands about ethics, culture, and society: reproductive success always wins. So if humanity wishes to achieve its stated long-term goals of giving people long and healthy lives while living sustainably on Earth, we'd better figure out how to align those goals with Nature's overriding law of reproductive fitness.
In another fun experiment, several human subjects were "locked up" at a zoo, and fed something like the diet of our closest primate relatives (chimps and gorillas), consisting of raw fruits and vegetables. It was mostly vegetables, if I remember correctly, lots of clips of people gnawing on carrots, raw broccoli, and the like. Long story short, everybody hated it. They spent about half the day doing nothing but chewing, and were starving nonetheless. I believe the average weight loss quoted was something like 10 pounds in two weeks (I meant to watch the show again and take notes, but this is the first "free" time I've gotten, and it's only because I'm at the park with the kids). Subjects apparently spoke of the desire for meat quite a bit (when they weren't bitching about all of the chewing and frequent bathroom visits). It's a fun experiment you can try at home yourself!
One part of the show which rather surprised me: one of the scientists visited a remote tribe in Africa who were still living a fairly primal hunter-gatherer existence. What struck me was that these people looked like crap, nothing like the sort of pictures taken by Weston A. Price, or the fossilized H. habilis jaws shown in the chewing experiment. Their faces showed signs of nutritional stress, with small jaws and crowded teeth. One hint here may be the effort they went through to get meat. In the show, they had a porcupine cornered in its burrow (BTW, this thing was huge, the size of a really big dog). The tribesmen spent the better part of the day digging 6-foot deep holes, until they forced the porcupine into the Hobson's choice of which hole to get speared in. It was a tremendous amount of effort to get some meat, and one of the hunters basically said "porcupine sucks, but at least it's meat". They also discussed how socially important it was for hunters to bring back meat, that it brought them status in the tribe, etc. Clearly, meat is at the top of the menu for these people. Yet that they would go to such lengths to obtain it (particularly when they find porcupine distasteful) makes me wonder if hunting isn't so good in this region anymore. Perhaps game has become scarce, hence the appearance of nutritional stress? Yet they're hanging in there, if nothing else a testament to the tremendous adaptability of humanity, made possible by our big brains (and what do you suppose made those big brains possible?)
Anyway, "How Food Made Us Human" has spawned a couple of trains of thought, which I want to share with you here. The first has to do with a mouse experiment demonstrated on the show; the second with the correlations between diet changes and physiological changes over the course of evolution.
The mouse experiment was very interesting, intended to show the effect of cooking on caloric bioavailability. Take some mice, feed them raw sweet potatoes, and measure the change in body mass as well as activity (based on distance run on the exercise wheel). Now cook the sweet potato and do the same thing. If you're still stuck in the calories-in calories-out (CICO) paradigm, the results should spawn massive cognitive dissonance. The mice who ate the cooked food showed the following differences when compared to those eating the raw food:
- They exercised significantly more, AND
- They were heavier.
Of course this all makes perfect sense when considered from the standpoint of evolution and metabolic regulation. Cooking makes calories more available. Though they didn't explicitly say so in the show, one presumes that the quantity of potato was held constant between the two groups (since not doing so would void the entire point of the experiment). So the only difference (presumably) was raw vs. cooked. Mice didn't evolve eating cooked food. The higher caloric availability likely "fooled" their digestive systems into taking up calories too rapidly, faster than required to support normal metabolic operations. Rate of digestion is regulated by hormonal and nervous feedback mechanisms: when the brain and other internal sensory systems think there's enough energy around, gastrointestinal motility decreases, slowing the rate at which food leaves the stomach to be digested and absorbed in the small intestine; and of course when an energy deficit is detected, food moves more rapidly out of the stomach. When the stomach is empty AND your body senses an energy deficit, you get hungry, and are driven to find more food.
That's how it supposed to work. Like all feedback control systems, if you push outside the "designed" range of stability, it starts failing. I expect this to be particularly the case with biological systems. Biological responses tend to follow "S-curve" shapes. There's nothing deep about this. It simply reflects the fact that biological responses are limited by available resources. At some point you run out of the capacity to make more hormones, neurotransmitters, receptors, etc. Insulin response is a great example. As a function of blood glucose, the secretion of insulin follows a shape much like that seen on the Wikipedia page. At some point you either saturate the ability to detect glucose, or saturate the ability of the pancreas to crank out insulin, or both. The point is that it is possible to exceed your body's ability to effectively control blood sugar levels via the action of insulin, simply by changing the effective "sugar density" of the food you consume.
Back to our mice: when faced with an excess of calories, how can the mouse's body respond? It can either store energy, or burn it off (or both). We know some of it got stored, as the mice got heavier. The show gave one example of "burning it off", in the spontaneous increase in activity. I don't know if they measured it, but I'd wager that the mice also gave off more heat, which I think is a more effective way dumping energy. Muscles are remarkably efficient, and it is surprising how much mechanical work you can get out of a kilocalorie, when compared to the equivalent thermal energy (1 kilocalorie will raise 1 kilogram of water only 1 degree C in temperature, but raise a 1 kg mass over 400 meters against gravity). So the outcome of the mouse experiment is wildly inconsistent with the CICO paradigm, but precisely what one might predict from evolution and metabolic regulation. It would be very interesting to see what would happen if the mice were allowed to continue eating cooked sweet potatoes for a longer time period. I wonder if they would develop mouse metabolic syndrome?
The second line of thought follows the main line of reasoning from the show, which is thus: by incorporating more nutrient dense foods into their diets, our hominid ancestors set in path a major evolutionary shift, where gut size was exchanged for brain size. The argument is elegant: if you eat food with greater bioavailable caloric density, you can spend less energy on digestion. That opens up an evolutionary pathway to increase brain size and energy expenditure at the expense of the gut, because you can extract the same energy from food with a smaller and less-demanding digestive system. And indeed, the fossil record seems to indicate that the major jumps in hominid brain sizes came at two critical nutritional junctures. The first was around the time we started eating meat. The second was when we started cooking food, and cooking is hypothesized to have led to modern humans.
It's interesting to consider the evolutionary advantage brought about by our big brains. What advantage did they bring our hominid ancestors? The scientist visiting the African hunter-gatherers went on a bit about how hunting is a fairly complex behavior, particularly as practiced by humans. But there's a lot more to it than that. The brain remembers - it stores information. And an "advanced" brain not only remembers information, but can extrapolate it to the future, making choices now that create advantages later. For instance, it's good to know that when the rains come, wildebeest are going to show up and a certain place, and that there's an effective method for cutting one out of the herd, how to make the tools you need to kill and butcher it, which parts are good to eat, etc. In the context of hunting and gathering, there's a positive feedback loop between the increase in nutrient density and encephalization, each reinforcing the other.
Of course, there's been another major shift in nutrient density since the advent of cooking: agriculture. The advent of agriculture is an interesting case. At first blush it doesn't seem so hot. The main thrust of human agriculture has been domestication of annual grasses for their seeds, i.e. grains. Across the world, in geographically separate locations, populations growing different crops (wheat, corn, rice) uniformly appear to show significant increases in the chronic "diseases of civilization". But evolution doesn't care if your teeth fall out or you drop dead from cancer at age 40. All evolution cares about is reproductive fitness, and agricultural humans had an undeniable reproductive advantage over hunter-gatherers; otherwise we wouldn't be having this conversation.
We had a hint from the mouse experiment above that an increase in dietary effective energy density could lead to "metabolic overload", exceeding the body's ability to balance and regulate the intake and expenditure of energy. And indeed, the evidence continues to mount that a good chunk of our modern epidemic of chronic diseases may be attributable to such metabolic malfunction. It makes me wonder what happened to our Australopithecus ancestors when they started eating meat: did they suffer metabolic disease as well? It's an academic question, of course, as chronic disease or no, meat-eating proved to increase reproductive success. We might ask a similar question about what occurred as cooking gained popularity. These are hard questions to answer from the fossil record. Agriculture happened much more recently, and further is amenable to archaeology (agriculturists tend to gather in large numbers in one spot, as opposed to wandering all over the place looking for food).
But here's a thought: we noted above that big brains are useful for remembering lots of stuff. This is important when living as a hunter-gatherer, because the dynamics of nature are complex. Maximizing reproductive potential in this context means being able to remember and extrapolate the myriad (and often subtle) cause-and-effect relationships of the natural world, along with whatever technological innovations are required to take advantage of this knowledge. This information does not get passed on genetically, but rather through communication, i.e. parents teaching children. Knowledge is power, in a very tangible sense, when talking about hunter-gatherer survival. Greater knowledge implies greater ability to obtain nutrient-dense food, hence greater reproductive fitness; it also means that it takes longer to get that knowledge into the brains of your offspring. It is often argued that diseases of civilization have little effect on evolution, because they generally kill you after the reproductive years. But that assumes the only information being passed along is genetic. If memories are also required for the reproductive success of your offspring, it pays to live long enough to pass along that information. And if you follow this line of reasoning, it's clear there's a volume of information at which the parent will not be able to effectively communicate the body of knowledge while still performing hunting and gathering activities required for survival. Enter Grandma and Grandpa. If the information volume for reproductive effectiveness is sufficiently large, it pays to live long enough to pass along that information to your offspring, their offspring, and so forth. Correspondingly, adoption of new dietary practices must either preserve this longevity, OR require less information to be effective.
So where does agriculture fit in? Is the adoption of agriculture, which brings with it ever-increasing energy density in food, driving us toward the next phase of "big brain" evolution? Good question - but consider this: how much do you need to know to be an effective agriculturist? I would argue rather little, compared to hunting and gathering. A hunter-gatherer may have thousands of foods in their diet, and they have to know where and when to find them, how to prepare them, etc. Agriculturists have relatively narrow diets, and there's a relatively simple and fixed pattern to the whole business: plow the land, plant the seeds, keep out the weeds, harvest. Lather, rinse, repeat. So I think you can argue that agriculture has a much smaller information burden than hunting/gathering. The tremendous technological increases since the advent of agriculture are a testament to how relatively little brain-power is needed for obtaining food anymore, as we apparently had plenty of spare brain capacity to monkey around with things not directly related to getting fed.
Now it is well known that brain volume decreased dramatically with the advent of agriculture. So did adult lifespan. Yet the agriculturists clearly laid the smack-down on the hunter gatherers, evolutionarily speaking. So neither long-term health nor brain size is a reproductive advantage once you start growing your own food (or at least the foods that our ancestors chose to cultivate). There's no point in fueling a big brain if you've got nothing to put in it. And there's no point in keeping old people around if they are not able to contribute directly to the reproductive fitness of their offspring. If you can't work the fields, don't make babies, and we don't need your accumulated wisdom, then you're pretty much just eating food better used for making more genetic copies. So for an agriculturist, dropping dead at 35 may actually have been an advantage.
It makes me wonder what direction agriculture (and more recently, industrial food processing) is driving our "humanness". Does the ever-growing energy density and general availability of food imply we'll evolve even smaller guts and bigger brains? I'll put my money on "No". After all, look around you: it's not like the smartest people are the most successful reproductively. You can damn near be vegetative, contribute nothing to society at all, yet we will ensure you've got all the Big Macs and Twinkies you can stuff in your face to fuel the generation of lots of babies to do the same thing. In our current environment, evolution favors being chronically ill and stupid. It doesn't really matter how much we wring our hands about ethics, culture, and society: reproductive success always wins. So if humanity wishes to achieve its stated long-term goals of giving people long and healthy lives while living sustainably on Earth, we'd better figure out how to align those goals with Nature's overriding law of reproductive fitness.
Friday, July 23, 2010
Cognitive Dissonance: Not Just for the Layperson
I must admit, I had not carefully read Dr. Campbell's "last word" from the "discussion" of his reply to Denise Minger. His refusal to engage in discussion told me everything I needed to know. But in spelunking around for something else on that page, I came across this quote:
Hmmm, I wonder what Campbell's definition of "uncivil" is? Seems to have some conceptual overlap with the second sentence, i.e. those who ask "superficial" questions are being "uncivil". The question in question came from me, and I'm glad to see it had one of the desired effect. My preferred outcome would have been that Dr. Campbell actually answered the question. Then I would have learned something. It is unfortunate that he instead evaded the question as above, because then all we learn is that a) he doesn't have an answer, but b) thinks he does, and is thrown into painful cognitive dissonance when confronted by the truth of his ignorance. The nonsense about there being a "symphony of mechanisms" is, I believe, a subtle trick played on Dr. Campbell by his own mind. There are indeed many possible causes, and may be several interacting processes. But he confuses "I don't know which of the many possibilities contributes to the effect" with "here is what we know, a complex process". Classic mental band-aid for cognitive dissonance.
Anyway, I think my goal has been accomplished. I wanted to know if Dr. Campbell had any relevant information. If not, I wanted him to publicly torpedo his own credibility. Mission accomplished. Next time he wants to show up and bash a low-carb or paleo book an Amazon, you have ample material to demonstrate his irrationality.
I had hoped to have had a civil discourse, but this is difficult when the questions come from uncivil people. I also don’t have time to answer superficial questions of others like ‘what is the detailed mechanism of protein induction of high cholesterol levels’ – that easily could become an entire but relatively useless dissertation when the “mechanism” most decidedly is a symphony of mechanisms, as I explained in our book. At this point, the far more important observation is the dramatic increase in serum cholesterol.
Hmmm, I wonder what Campbell's definition of "uncivil" is? Seems to have some conceptual overlap with the second sentence, i.e. those who ask "superficial" questions are being "uncivil". The question in question came from me, and I'm glad to see it had one of the desired effect. My preferred outcome would have been that Dr. Campbell actually answered the question. Then I would have learned something. It is unfortunate that he instead evaded the question as above, because then all we learn is that a) he doesn't have an answer, but b) thinks he does, and is thrown into painful cognitive dissonance when confronted by the truth of his ignorance. The nonsense about there being a "symphony of mechanisms" is, I believe, a subtle trick played on Dr. Campbell by his own mind. There are indeed many possible causes, and may be several interacting processes. But he confuses "I don't know which of the many possibilities contributes to the effect" with "here is what we know, a complex process". Classic mental band-aid for cognitive dissonance.
Anyway, I think my goal has been accomplished. I wanted to know if Dr. Campbell had any relevant information. If not, I wanted him to publicly torpedo his own credibility. Mission accomplished. Next time he wants to show up and bash a low-carb or paleo book an Amazon, you have ample material to demonstrate his irrationality.
Thursday, July 22, 2010
What T. Colin Campbell Didn't Want You to See
T. Colin Campbell has chosen to not participate in any discussion of his own "scientific results". Take a look at his last word on the topic, note metadiscussion of what "science is about" rather than actually discussing any science, and check the shoes.
The great thing about the Internet, of course, is that it is impossible to censor anything. I'm pasting the comments I submitted to Campbell's site below. These were not approved. Compare with the openness displayed by Denise Minger in publishing comments from all comers, and fostering open discussion. Draw your own conclusions. If you have submitted comments to campbellcoalition.com that were not published, feel free to post them in the comments here. I'll send through anything that isn't overt spam.
To be fair, these comments may yet show up. There is a perfectly acceptable explanation that they haven't been published yet. I'm sure most bloggers have experienced "falling behind in comment moderation". If these comments are published, I partly retract my criticism. But the main portion remains valid: exchange of information is crucial to scientific progress. If you're not willing to exchange information, you're not interested in scientific progress.
I posted this just because it seemed odd to be revising such a benign comment. Who does this, and why?
The great thing about the Internet, of course, is that it is impossible to censor anything. I'm pasting the comments I submitted to Campbell's site below. These were not approved. Compare with the openness displayed by Denise Minger in publishing comments from all comers, and fostering open discussion. Draw your own conclusions. If you have submitted comments to campbellcoalition.com that were not published, feel free to post them in the comments here. I'll send through anything that isn't overt spam.
To be fair, these comments may yet show up. There is a perfectly acceptable explanation that they haven't been published yet. I'm sure most bloggers have experienced "falling behind in comment moderation". If these comments are published, I partly retract my criticism. But the main portion remains valid: exchange of information is crucial to scientific progress. If you're not willing to exchange information, you're not interested in scientific progress.
I posted this just because it seemed odd to be revising such a benign comment. Who does this, and why?
Uh, why did your answer to my original question change from ““Dr. Campbell said he will be able to post comments now and then, although he cannot respond to every question.” to “Dr. Campbell said he will participate to the extent possible.”? Those seem like they say the same thing to me.
At any rate, I expect Dr. Campbell will find it a better use of his time to respond to specific points here rather than having to write lengthy detailed work such as above.
Here's a harder question:
From the response above:
“First and foremost, our extensive work on the biochemical fundamentals of the casein effect on experimental cancer in laboratory animals (only partly described in our book) was prominent because these findings led to my suggestion of fundamental principles and concepts that apply to the broader effects of nutrition on cancer development.”
Can you explain what these fundamental principles might be, or at least direct me to a detailed discussion? Proteins are broken down in to amino acids in the gut (at least in healthy individuals). These amino acids are then transported throughout the body, where they may be used to build new proteins. How does a specific mixture of amino acids trigger cancer growth? And of course I doubt most free-living organisms eat large quantities of isolated casein. So if I eat a meal containing casein, the mixture of amino acids absorbed reflects that off the total protein content of the meal, not just the casein.
It seems that in order for casein to have a specific role, it would need to trigger some other biological response beyond it’s simple amino acid content. For example, we know that most cancers have a very high glucose requirement, as they largely rely on anaerobic glucose metabolism for energy. We might then expect insulin to be required to stimulate glucose transport. Some cancers do indeed show higher expression of insulin receptors, see e.g.
http://cancerres.aacrjournals.org/content/52/14/3924.abstract
From this we might hypothesize that dietary carbohydrates would drive cancer growth by providing both a supply a glucose and increased insulin secretion. It further can encompass other observations, e.g. the association of dietary fat and cancer. When eaten in combination with carbohydrate, fat will amplify insulin secretion.
Returning to your hypothesis that casein has a unique potential to stimulate cancer growth. What metabolic pathways are followed that create the “casein effect”? Is there some specific hormonal signal uniquely stimulated by casein?
And a link to a multivariate analysis that would answer at least some of Dr. Campbell's objections:
Here is an interesting blog on a multivariate analysis of China Study data:
http://healthcorrelator.blogspot.com/2010/07/china-study-again-multivariate-analysis.html
I put these comments under the post "The Challenge of Telling the Truth:
Nelson,
Your suggestion about keeping an “open attitude” is a good one. However, you need to keep an open attitude about scientific evidence as well. The way you talk about “truth of health” sounds a lot more like religion than science. Perhaps this is simply a communication gap. I sincerely hope that you and your father have the sort of open and inquisitive minds required for scientific progress. There is no absolute “truth” in science, as this would imply we have perfect information. I doubt even the staunchest supporter of any dietary dogma would claim that we have perfect understanding of the deep complexities of human biology.
I will reiterate here what I have said elsewhere: scientific progress is about two-way communication. You and your father likely have information that supports your hypotheses, information that others do not have. However, I’m sure you’d agree that others have information that you do not as well. The only way to reach “agreement” is communication, so we’re all on the same page. This is why dialog is so fundamental to scientific progress. I hope you and your father will participate in this dialog.
---------
“Despite lacking an adequate understanding of statistics and causality, this person used her intelligence and writing skills to compose a critique that might seem persuasive to laypeople.”
You might wish to expand on this a bit. It sounds like you’re saying she is both stupid (“lacking…understanding”) and intelligent in the same sentence. And I’m sure you would agree that “laypeople” need to have greater understanding of the issues so that they can make informed decisions, rather than simply picking an “expert” to blindly follow. Perhaps you can provide a little Statistics 101 discussion for us to better illustrate the shortcomings in Ms. Minger’s analysis for the lay public?
Yes, We Have No Bananas
Just a very quick post. It's been almost a week since I submitted my registration for 30bananasaday.com. Prolific commenter "durianrider" is one of the principles at this site. You can read some of his "insightful" comments on the last post. Note, however, the one question I asked repeatedly, to which he gives no attention. Not only do I think I will never get approved to post on 30bananasaday.com, I doubt I'll even get a reason. Draw your own conclusions.
Another interesting development is the new(ish) web site campbellcoalition.com. Dr. Campbell's response to Denise Minger's critique is featured prominently, and better yet, Dr. Campbell has indicated that he may participate in some discussion here. I've posted a few questions, and urge others to do the same. I recommend you focus the discussion on scientific topics, as opposed to his opinion of Denise Minger, etc. Come armed with some hard questions on the connections between nutrition and metabolism, particular as they relate to Dr. Campbell's hypotheses. I believe this exercise has two realistic outcomes: either Dr. Campbell has some answers (which actually would be very cool), or he stonewalls. Either way we learn something interesting.
*** UPDATE ***
Well, it didn't take long for us to learn something interesting. From the comments on Dr. Campbell's reply to Denise Minger:
In other words, Dr. Campbell is going to have the last word, like it or not. So much for scientific discourse. The Campbells certainly could have chosen the path taken by Denise Minger - posting all discussion, whether "civil" or not, and choosing the reply to those questions or issues that are clearly intended to foster scientific discussion, and ignoring ad hominem attacks etc. Dr. Campbell's chosen course speaks to his true motivations.
If you have questions you posted to Campbell's site which did not make it through moderation, I invite you to repost in the comments here. Others can then see exactly what offended Dr. Campbell so greatly that he opted out of the discussion.
Another interesting development is the new(ish) web site campbellcoalition.com. Dr. Campbell's response to Denise Minger's critique is featured prominently, and better yet, Dr. Campbell has indicated that he may participate in some discussion here. I've posted a few questions, and urge others to do the same. I recommend you focus the discussion on scientific topics, as opposed to his opinion of Denise Minger, etc. Come armed with some hard questions on the connections between nutrition and metabolism, particular as they relate to Dr. Campbell's hypotheses. I believe this exercise has two realistic outcomes: either Dr. Campbell has some answers (which actually would be very cool), or he stonewalls. Either way we learn something interesting.
*** UPDATE ***
Well, it didn't take long for us to learn something interesting. From the comments on Dr. Campbell's reply to Denise Minger:
Based on the response received thus far, we have determined that our prior idea of a reasoned and civil discourse, with participation by Dr. Campbell, is not feasible and have decided to discontinue this discussion thread. Before closing, however, Dr. Campbell wanted to respond to comments from Denise Minger. Her comments are posted above, and Dr. Campbell’s response follows.
In other words, Dr. Campbell is going to have the last word, like it or not. So much for scientific discourse. The Campbells certainly could have chosen the path taken by Denise Minger - posting all discussion, whether "civil" or not, and choosing the reply to those questions or issues that are clearly intended to foster scientific discussion, and ignoring ad hominem attacks etc. Dr. Campbell's chosen course speaks to his true motivations.
If you have questions you posted to Campbell's site which did not make it through moderation, I invite you to repost in the comments here. Others can then see exactly what offended Dr. Campbell so greatly that he opted out of the discussion.
Friday, July 16, 2010
Going Bananas
I got an "interesting" comment on my last post about Denise Minger's critique of "The China Study". It's the one from "durianrider" - check it out, particularly his "challenge". I've already answered the challenge, but invite others to also provide information about any elite non-vegan athletes they may know of. I have no illusions that we'll change durianrider's mind, or that of any "true believer", but the way to counter misinformation is with good information. Individuals need all the information they can get to make informed decisions, so let's make sure they get it, and support their right for informed choice. Personally, if you choose to be a vegan, that's fine with me. I have no stake in your personal lifestyle choice, but I do want to help people at least make that choice an informed one, rather than one based the propaganda of zealots.
And T. Colin Campbell, if you're out there, let's see if you have the courage of your convictions. I have a Ph.D. and was an academic research scientist for many years, so I should be "worthy" of scientific discourse with you. And discourse is at the root of scientific progress. How can you expect to educate people like me on your views if you are unwilling to discuss them with opponents in a public forum?
Related note: durianrider is also one of the principals of the 30bananasaday.com site, along with "freelee". Some of the discussion on the post "Debunking the China Study Critics" is pretty interesting, from a sociological point of view. I am going to try registering for the site, and see if they have any willingness to let in opposing views. The registration page and forum guidelines make me suspect they are intolerant of those who might not agree with them, e.g. this quote:
One of the best signs of dogmatic belief is the intolerance of information which contradicts said belief. I'll reserve judgment on 30bananasaday.com until my application gets accepted or rejected, as I plan to make it quite clear that I will be providing evidence that runs counter to their mission.
For my part, I welcome discussion from all corners, provided it is reasonably civil (i.e. contains actual information rather than emotional spewing). The definition of rationality is that two people with the same information will draw the same conclusions. But the only way those two people can achieve the same state of information is through communication. Even if you completely disagree with my views, there's a reasonable chance that I will learn something from you which may help me make better choices. So bring it on!
And T. Colin Campbell, if you're out there, let's see if you have the courage of your convictions. I have a Ph.D. and was an academic research scientist for many years, so I should be "worthy" of scientific discourse with you. And discourse is at the root of scientific progress. How can you expect to educate people like me on your views if you are unwilling to discuss them with opponents in a public forum?
Related note: durianrider is also one of the principals of the 30bananasaday.com site, along with "freelee". Some of the discussion on the post "Debunking the China Study Critics" is pretty interesting, from a sociological point of view. I am going to try registering for the site, and see if they have any willingness to let in opposing views. The registration page and forum guidelines make me suspect they are intolerant of those who might not agree with them, e.g. this quote:
We will not tolerate "anti-fruit" posts or advice that recommends calorie restriction/or the suggestion that others are "overeating on fruit", also recommending others restrict their water intake will not be supported on 30BaD, these threads will be deleted and you will be given a warning. This advice is not only unproductive but dangerous to the health of our members.
One of the best signs of dogmatic belief is the intolerance of information which contradicts said belief. I'll reserve judgment on 30bananasaday.com until my application gets accepted or rejected, as I plan to make it quite clear that I will be providing evidence that runs counter to their mission.
For my part, I welcome discussion from all corners, provided it is reasonably civil (i.e. contains actual information rather than emotional spewing). The definition of rationality is that two people with the same information will draw the same conclusions. But the only way those two people can achieve the same state of information is through communication. Even if you completely disagree with my views, there's a reasonable chance that I will learn something from you which may help me make better choices. So bring it on!
Friday, July 9, 2010
The China Study: Crushed by its Own Data
You may have already seen this outstanding analysis of the data from "The China Study". If you haven't, I highly recommend you give it a read. It's long, but well worth the effort. Readers of this blog know my opinion of T. Colin Campbell and his "scientific" work. Now somebody has taken the time to actually crunch the numbers, using Campbell's own data to demonstrate that his conclusions are baseless (at least when confined to this data), and probably the result of confirmation bias.
I also love the observation that, despite his constant whining about the "dangers of reductionism" in science, Campbell's entire argument against animal protein really hinges on a strongly reductionist experiment, namely the isolated effect of casein fed to rats in large doses. Snap!
Readers know of my criticisms of classical statistics, but it should be noted that I don't really have a problem with the mathematics, but the application. Math is what it is, either right or wrong. My issue is that classical statistics is used incorrectly, to draw inferences about hypotheses, when the underlying mathematical framework has nothing to do with inference. The key problem is that "statistics" are just numbers derived from data, like correlations. They don't say anything about a hypothesis: you will calculate the same correlation between two datasets, regardless of your hypothesis about what causes that correlation. Anyway, I don't want to get off on a rant. My point here is that the author, Denise Minger, does an excellent job of confining her analysis and conclusions within the bounds of what classical statistics can tell you. And along the way, she does a great job of demonstrating how easy it is to fool yourself (as T. Colin Campbell did - repeatedly) by over-interpreting these numbers which, in the end, cannot tell you anything more than what's in the data.
Ms. Minger has also done a great service in providing a concrete example of the issues in observational studies. You've likely read often that epidemiological studies are of little use in distinguishing between competing hypotheses. Now you have an example, replete with numbers. Ms. Minger demonstrates in several cases how a seemingly "obvious" conclusion vanishes once you dig into the large number of uncontrolled variables inherent in all observational studies. It's easy to find correlations in large datasets with many uncontrolled variables. The problem is that people take these correlations to mean more (or less) than they really do in terms of supporting/undermining a particular hypothesis, and the conclusions they draw are essentially ad hoc, not based on any rigorous mathematical analysis, but rather hand-waving about what is "obvious". An oft-quoted example is that men who shave daily have a higher incidence of heart disease. It is "obvious" that heart disease is not caused by shaving, right? Or is it? There's a whole lot of other information that goes into that judgment. We generally take this sort of thing for granted, especially when made in pronouncements from "esteemed" scientists like T. Colin Campbell. But if you dig into the reasoning behind these conclusions, you generally find a tangled web of assumptions, hypotheses assumed to be true, but which have varying (if any) actual evidence to support them. Ms. Minger does a great job of teasing these out of Campbell's reasoning, and demonstrating how the data itself provides little evidence one way or another, precisely because it cannot distinguish between the potential effects of the many intertwined and uncontrolled variables.
Anyway, enough of my babbling. Go read the article, you'll be glad you did (unless you're an uncritical fan of T. Colin Campbell, in which case you've got bigger problems).
I also love the observation that, despite his constant whining about the "dangers of reductionism" in science, Campbell's entire argument against animal protein really hinges on a strongly reductionist experiment, namely the isolated effect of casein fed to rats in large doses. Snap!
Readers know of my criticisms of classical statistics, but it should be noted that I don't really have a problem with the mathematics, but the application. Math is what it is, either right or wrong. My issue is that classical statistics is used incorrectly, to draw inferences about hypotheses, when the underlying mathematical framework has nothing to do with inference. The key problem is that "statistics" are just numbers derived from data, like correlations. They don't say anything about a hypothesis: you will calculate the same correlation between two datasets, regardless of your hypothesis about what causes that correlation. Anyway, I don't want to get off on a rant. My point here is that the author, Denise Minger, does an excellent job of confining her analysis and conclusions within the bounds of what classical statistics can tell you. And along the way, she does a great job of demonstrating how easy it is to fool yourself (as T. Colin Campbell did - repeatedly) by over-interpreting these numbers which, in the end, cannot tell you anything more than what's in the data.
Ms. Minger has also done a great service in providing a concrete example of the issues in observational studies. You've likely read often that epidemiological studies are of little use in distinguishing between competing hypotheses. Now you have an example, replete with numbers. Ms. Minger demonstrates in several cases how a seemingly "obvious" conclusion vanishes once you dig into the large number of uncontrolled variables inherent in all observational studies. It's easy to find correlations in large datasets with many uncontrolled variables. The problem is that people take these correlations to mean more (or less) than they really do in terms of supporting/undermining a particular hypothesis, and the conclusions they draw are essentially ad hoc, not based on any rigorous mathematical analysis, but rather hand-waving about what is "obvious". An oft-quoted example is that men who shave daily have a higher incidence of heart disease. It is "obvious" that heart disease is not caused by shaving, right? Or is it? There's a whole lot of other information that goes into that judgment. We generally take this sort of thing for granted, especially when made in pronouncements from "esteemed" scientists like T. Colin Campbell. But if you dig into the reasoning behind these conclusions, you generally find a tangled web of assumptions, hypotheses assumed to be true, but which have varying (if any) actual evidence to support them. Ms. Minger does a great job of teasing these out of Campbell's reasoning, and demonstrating how the data itself provides little evidence one way or another, precisely because it cannot distinguish between the potential effects of the many intertwined and uncontrolled variables.
Anyway, enough of my babbling. Go read the article, you'll be glad you did (unless you're an uncritical fan of T. Colin Campbell, in which case you've got bigger problems).
Subscribe to:
Posts (Atom)
