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brdgt
A short one to start off with - I've said it before and I'll say it again: we need to pay more attention to heat waves; they kill more people in the United States every year than all other natural disasters combined. And, as this article indicates, it's not just a matter of "sucking it up, it's summer."
Heat Waves Are Getting Longer
By ANDREW C. REVKIN, The New York Times, August 7, 2007
Researchers studying western European temperature records have found that the length of heat waves there has doubled since 1880, from 1.5 days to 3 days on average. They also say that the number of summer days that are far hotter than the average for a particular date has tripled. The team described its work in the current issue of the Journal of Geophysical Research-Atmospheres. The scientists, led by Paul M. Della-Marta of the University of Bern in Switzerland, said the findings supported the idea that global warming from human activities could be making Europe more prone to extreme conditions. They recommended that health agencies in the region work on ways to limit human health risks from summer heat.
This is one that I've noticed anecdotally. I have very fair skin and burn easily, but even after SPF 15, I don't notice much of a difference in protection.
Really? The Claim: With Sunscreens, High SPF Ratings Are Best
By ANAHAD O’CONNOR, The New York Times, August 7, 2007
THE FACTS
Everyone knows that an SPF rating of 60 provides double the protection of SPF 30 — or does it?
Studies over the years have shown that sunscreen with an SPF, or sun protection factor, of 30 blocks about 97 percent of ultraviolet rays. A rating of 15 means 93 percent of UV rays are blocked, and anything higher than 30 remains in the 97 or 98 percent range.
In 1999 the Food and Drug Administration recommended that sunscreens with an SPF higher than 30 be labeled “30+,” mostly to prevent people from developing a false sense of security that might lead them to spend more time in the sun.
What many people do not realize is that the amount of sunscreen applied plays an enormous role. A study in The British Journal of Dermatology this year found that applying less than two ounces over the entire body at one time can leave people with an SPF rating far lower than what is on the bottle. Some studies have shown that people typically apply just 10 percent of the amount recommended.
It is also important to look for sunscreens that protect against UVA and UVB radiation. SPF ratings apply only to UVB rays, and some sunscreens provide no protection at all against UVA rays, which penetrate the skin more deeply. For broad protection, look for sunscreens with avobenzene, zinc oxide or titanium dioxide, all of which block UVA.
THE BOTTOM LINE
Above SPF 30, the increased protection is minimal.
I just love Natalie Angier...
Basics: Its Poor Reputation Aside, Our Fat Is Doing Us a Favor
By NATALIE ANGIER, The New York Times, August 7, 2007
In this country, the most popular cosmetic surgery procedure is liposuction: doctors vacuum out something like two million pounds of fat from the thighs, bellies, buttocks, jowls and man-breasts of 325,000 people a year. What happens to all that extracted adipose tissue? It’s bagged and disposed of as medical waste; or maybe, given the recent news about socially contagious fat, it’s sent by FedEx to the patients’ old college chums. But one thing the fat surely is not, and that is given due thanks for serving as scapegoat, and for a job well done.
We are now in what feels like the 347th year of the fastidiously vilified “obesity epidemic.” Health officials repeatedly warn that everywhere in the world people are gaining too much weight and putting themselves at risk of diabetes, high blood pressure, heart disease and other obesity-linked illnesses, not to mention taking up more than their fair share of molded plastic subway seat.
It’s easy to fear and despise our body fat and to see it as an unnatural, inert, pointless counterpoint to all things phat and fabulous. Yet fat tissue is not the problem here, and to castigate fat for getting too big and to blame it for high blood pressure or a wheezing heart is like a heavy drinker blaming the liver for turning cirrhotic. Just as the lush’s liver was merely doing its hepatic best to detoxify the large quantities of liquor in which it was doused, and just as the alcoholic would have been far worse off had the liver not been playing Hepa-filter in the first place, so our fat tissue, by efficiently absorbing the excess packets of energy we put in our mouths, has our best interests at heart.
“Obesity is not due to any defect in adipose tissue per se; it’s an issue of energy balance,” said Bruce M. Spiegelman of the Dana-Farber Cancer Institute in Boston. If you are consuming too many calories relative to what you burn off, the body must cope with that energy surplus, he said, “and adipose tissue is the proper place for it.”
“If you had no fat cells, no adipose tissue, you’d still be out of energy balance, and you’d put the excess energy somewhere else,” he said, at which point really bad things can happen. Consider the lipodystrophy diseases, rare metabolic disorders in which the body lacks fat tissue and instead dumps its energy overruns in that jack-of-all-organs, the liver, causing extreme liver swelling, liver failure and sometimes liver-bearer death.
“Some adipose tissue is a good thing,” said Barbara Kahn, chief of the endocrinology, diabetes and metabolism division at Beth Israel Deaconess Medical Center, at Harvard.
Indeed, evolutionary biologists have proposed that our relative plumpness compared with our closest nonhuman kin, the chimpanzee, may help explain our relative braininess. Even a lean male athlete with a body fat content of 8 percent to 10 percent of total body mass (half the fat found on the average nonobese, non-Olympic American man) is still a few percentage points more marbled than a wild male chimpanzee, and scientists have suggested that our distinctive adipose stores help ensure that our big brains will be fed even when our cupboards go bare.
Scientists who study fat emphasize that its bland and amorphous appearance notwithstanding, our adipose depots represent highly specialized organs, as finely honed to the task of energy storage as muscle is built for flexing. Our body fat is made of some 40 billion fat cells, or adipocytes, and their supportive matrix, with most of the bulk stashed under the skin but also threaded viscerally, around and between other organs. Each fat cell is essentially a bouncing balloon filled with those greasy lipids we call triglycerides, three fatty acid chains of mostly carbons and hydrogens arrayed in high-energy configurations that explain why, gram for gram, dietary fat has more than twice the calories of meat or starch; and every fatty acid trio is tacked to a sugar-sweet glycerol frame.
In most body cells, the watery cytoplasm where the labor of proteins takes place accounts for maybe 70 percent of the cell’s volume, with another 10 percent given over to the nucleus, seat of the cell’s DNA. In a fat cell, by contrast, lipids are king, queen and bishop, and the checkerboard, too. They fill more than 95 percent of the adipocyte volume, crowding the cytoplasm with its proteins and the nucleus with its genes up against the cell wall in what Dr. Kahn calls “a crescent moon space.”
Yet for all its lipid density, the average fat cell is ever primed to hoard more, to take in more fatty acids and sugars from the blood and stitch them into triglyceride stores, and to swell to several times its cellular waistline of yore. Most weight that we gain and lose in life is the result of our existing fat cells growing and shrinking, absorbing and releasing energy-rich lipids as needed, depending on our diet and exercise regimens of the moment. But when exposed to chronic caloric overload, fat cells will initiate cell division to augment the supply; and because fat cells, like muscle cells, rarely turn over and die, those new lipidinous recruits will be your helpmeets for life.
Fat is no rutabaga. It is dynamic and mercantile, exchanging chemical signals with the brain, bones, gonads and immune system, and with every energy manager on the body’s long alimentary train.
“We used to think of an adipose cell as an inert storage depot,” Dr. Kahn said. “Now we appreciate that it is an endocrine organ,” in other words, an organ that like the thyroid or pancreas, secretes hormones to shape the behavior of other tissues far and wide. Squashed to the side a fat cell’s cytoplasm may be, but it nevertheless spins out a steady supply of at least 20 different hormones. Key among them is leptin, an essential player in reproduction. Scientists suspect that a girl enters puberty when her fat stores become sufficiently dense to begin releasing leptin, which signals the brain to set the pulsing axis of gonadal hormones in motion.
Fat also seems to know when it is getting out of hand, and it may resist new personal growth. Dr. Spiegelman and others have shown that with the onset of obesity — defined as 25 or more pounds above one’s ideal weight — the fat tissue starts releasing potent inflammatory hormones. That response is complex and harmful in the long run. But in the short term, said Dr. Spiegelman, “inflammation clearly has an anti-obesity effect, and it may be the body’s attempt to restrain further accumulation of adipose tissue.” The fat sizes up the risks and benefits, and it takes its fat chance.
I especially like her because she's an evolutionary psychologist without the determinism, unlike many others *cough*see below*cough* If you haven't read her book, Woman: An Intimate Geography you really should.
In Dusty Archives, a Theory of Affluence
By NICHOLAS WADE, The New York Times, August 7, 2007
For thousands of years, most people on earth lived in abject poverty, first as hunters and gatherers, then as peasants or laborers. But with the Industrial Revolution, some societies traded this ancient poverty for amazing affluence.
Historians and economists have long struggled to understand how this transition occurred and why it took place only in some countries. A scholar who has spent the last 20 years scanning medieval English archives has now emerged with startling answers for both questions.
Gregory Clark, an economic historian at the University of California, Davis, believes that the Industrial Revolution — the surge in economic growth that occurred first in England around 1800 — occurred because of a change in the nature of the human population. The change was one in which people gradually developed the strange new behaviors required to make a modern economy work. The middle-class values of nonviolence, literacy, long working hours and a willingness to save emerged only recently in human history, Dr. Clark argues.
Because they grew more common in the centuries before 1800, whether by cultural transmission or evolutionary adaptation, the English population at last became productive enough to escape from poverty, followed quickly by other countries with the same long agrarian past.
Dr. Clark’s ideas have been circulating in articles and manuscripts for several years and are to be published as a book next month, “A Farewell to Alms” (Princeton University Press). Economic historians have high praise for his thesis, though many disagree with parts of it.
“This is a great book and deserves attention,” said Philip Hoffman, a historian at the California Institute of Technology. He described it as “delightfully provocative” and a “real challenge” to the prevailing school of thought that it is institutions that shape economic history.
Samuel Bowles, an economist who studies cultural evolution at the Santa Fe Institute, said Dr. Clark’s work was “great historical sociology and, unlike the sociology of the past, is informed by modern economic theory.”
The basis of Dr. Clark’s work is his recovery of data from which he can reconstruct many features of the English economy from 1200 to 1800. From this data, he shows, far more clearly than has been possible before, that the economy was locked in a Malthusian trap _ — each time new technology increased the efficiency of production a little, the population grew, the extra mouths ate up the surplus, and average income fell back to its former level.
This income was pitifully low in terms of the amount of wheat it could buy. By 1790, the average person’s consumption in England was still just 2,322 calories a day, with the poor eating a mere 1,508. Living hunter-gatherer societies enjoy diets of 2,300 calories or more.
“Primitive man ate well compared with one of the richest societies in the world in 1800,” Dr. Clark observes.
The tendency of population to grow faster than the food supply, keeping most people at the edge of starvation, was described by Thomas Malthus in a 1798 book, “An Essay on the Principle of Population.” This Malthusian trap, Dr. Clark’s data show, governed the English economy from 1200 until the Industrial Revolution and has in his view probably constrained humankind throughout its existence. The only respite was during disasters like the Black Death, when population plummeted, and for several generations the survivors had more to eat.
Malthus’s book is well known because it gave Darwin the idea of natural selection. Reading of the struggle for existence that Malthus predicted, Darwin wrote in his autobiography, “It at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. ... Here then I had at last got a theory by which to work.”
Given that the English economy operated under Malthusian constraints, might it not have responded in some way to the forces of natural selection that Darwin had divined would flourish in such conditions? Dr. Clark started to wonder whether natural selection had indeed changed the nature of the population in some way and, if so, whether this might be the missing explanation for the Industrial Revolution.
The Industrial Revolution, the first escape from the Malthusian trap, occurred when the efficiency of production at last accelerated, growing fast enough to outpace population growth and allow average incomes to rise. Many explanations have been offered for this spurt in efficiency, some economic and some political, but none is fully satisfactory, historians say.
Dr. Clark’s first thought was that the population might have evolved greater resistance to disease. The idea came from Jared Diamond’s book “Guns, Germs and Steel,” which argues that Europeans were able to conquer other nations in part because of their greater immunity to disease.
In support of the disease-resistance idea, cities like London were so filthy and disease ridden that a third of their populations died off every generation, and the losses were restored by immigrants from the countryside. That suggested to Dr. Clark that the surviving population of England might be the descendants of peasants.
A way to test the idea, he realized, was through analysis of ancient wills, which might reveal a connection between wealth and the number of progeny. The wills did that, , but in quite the opposite direction to what he had expected.
Generation after generation, the rich had more surviving children than the poor, his research showed. That meant there must have been constant downward social mobility as the poor failed to reproduce themselves and the progeny of the rich took over their occupations. “The modern population of the English is largely descended from the economic upper classes of the Middle Ages,” he concluded.
As the progeny of the rich pervaded all levels of society, Dr. Clark considered, the behaviors that made for wealth could have spread with them. He has documented that several aspects of what might now be called middle-class values changed significantly from the days of hunter gatherer societies to 1800. Work hours increased, literacy and numeracy rose, and the level of interpersonal violence dropped.
Another significant change in behavior, Dr. Clark argues, was an increase in people’s preference for saving over instant consumption, which he sees reflected in the steady decline in interest rates from 1200 to 1800.
“Thrift, prudence, negotiation and hard work were becoming values for communities that previously had been spendthrift, impulsive, violent and leisure loving,” Dr. Clark writes.
Around 1790, a steady upward trend in production efficiency first emerges in the English economy. It was this significant acceleration in the rate of productivity growth that at last made possible England’s escape from the Malthusian trap and the emergence of the Industrial Revolution.
In the rest of Europe and East Asia, populations had also long been shaped by the Malthusian trap of their stable agrarian economies. Their workforces easily absorbed the new production technologies that appeared first in England.
It is puzzling that the Industrial Revolution did not occur first in the much larger populations of China or Japan. Dr. Clark has found data showing that their richer classes, the Samurai in Japan and the Qing dynasty in China, were surprisingly unfertile and so would have failed to generate the downward social mobility that spread production-oriented values in England.
After the Industrial Revolution, the gap in living standards between the richest and the poorest countries started to accelerate, from a wealth disparity of about 4 to 1 in 1800 to more than 50 to 1 today. Just as there is no agreed explanation for the Industrial Revolution, economists cannot account well for the divergence between rich and poor nations or they would have better remedies to offer.
Many commentators point to a failure of political and social institutions as the reason that poor countries remain poor. But the proposed medicine of institutional reform “has failed repeatedly to cure the patient,” Dr. Clark writes. He likens the “cult centers” of the World Bank and International Monetary Fund to prescientific physicians who prescribed bloodletting for ailments they did not understand.
If the Industrial Revolution was caused by changes in people’s behavior, then populations that have not had time to adapt to the Malthusian constraints of agrarian economies will not be able to achieve the same production efficiencies, his thesis implies.
Dr. Clark says the middle-class values needed for productivity could have been transmitted either culturally or genetically. But in some passages, he seems to lean toward evolution as the explanation. “Through the long agrarian passage leading up to the Industrial Revolution, man was becoming biologically more adapted to the modern economic world,” he writes. And, “The triumph of capitalism in the modern world thus may lie as much in our genes as in ideology or rationality.”
What was being inherited, in his view, was not greater intelligence — being a hunter in a foraging society requires considerably greater skill than the repetitive actions of an agricultural laborer. Rather, it was “a repertoire of skills and dispositions that were very different from those of the pre-agrarian world.”
Reaction to Dr. Clark’s thesis from other economic historians seems largely favorable, although few agree with all of it, and many are skeptical of the most novel part, his suggestion that evolutionary change is a factor to be considered in history.
Historians used to accept changes in people’s behavior as an explanation for economic events, like Max Weber’s thesis linking the rise of capitalism with Protestantism. But most have now swung to the economists’ view that all people are alike and will respond in the same way to the same incentives. Hence they seek to explain events like the Industrial Revolution in terms of changes in institutions, not people.
Dr. Clark’s view is that institutions and incentives have been much the same all along and explain very little, which is why there is so little agreement on the causes of the Industrial Revolution. In saying the answer lies in people’s behavior, he is asking his fellow economic historians to revert to a type of explanation they had mostly abandoned and in addition is evoking an idea that historians seldom consider as an explanatory variable, that of evolution.
Most historians have assumed that evolutionary change is too gradual to have affected human populations in the historical period. But geneticists, with information from the human genome now at their disposal, have begun to detect ever more recent instances of human evolutionary change like the spread of lactose tolerance in cattle-raising people of northern Europe just 5,000 years ago. A study in the current American Journal of Human Genetics finds evidence of natural selection at work in the population of Puerto Rico since 1513. So historians are likely to be more enthusiastic about the medieval economic data and elaborate time series that Dr. Clark has reconstructed than about his suggestion that people adapted to the Malthusian constraints of an agrarian society.
“He deserves kudos for assembling all this data,” said Dr. Hoffman, the Caltech historian, “but I don’t agree with his underlying argument.”
The decline in English interest rates, for example, could have been caused by the state’s providing better domestic security and enforcing property rights, Dr. Hoffman said, not by a change in people’s willingness to save, as Dr. Clark asserts.
The natural-selection part of Dr. Clark’s argument “is significantly weaker, and maybe just not necessary, if you can trace the changes in the institutions,” said Kenneth L. Pomeranz, a historian at the University of California, Irvine. In a recent book, “The Great Divergence,” Dr. Pomeranz argues that tapping new sources of energy like coal and bringing new land into cultivation, as in the North American colonies, were the productivity advances that pushed the old agrarian economies out of their Malthusian constraints.
Robert P. Brenner, a historian at the University of California, Los Angeles, said although there was no satisfactory explanation at present for why economic growth took off in Europe around 1800, he believed that institutional explanations would provide the answer and that Dr. Clark’s idea of genes for capitalist behavior was “quite a speculative leap.”
Dr. Bowles, the Santa Fe economist, said he was “not averse to the idea” that genetic transmission of capitalist values is important, but that the evidence for it was not yet there. “It’s just that we don’t have any idea what it is, and everything we look at ends up being awfully small,” he said. Tests of most social behaviors show they are very weakly heritable.
He also took issue with Dr. Clark’s suggestion that the unwillingness to postpone consumption, called time preference by economists, had changed in people over the centuries. “If I were as poor as the people who take out payday loans, I might also have a high time preference,” he said.
Dr. Clark said he set out to write his book 12 years ago on discovering that his undergraduates knew nothing about the history of Europe. His colleagues have been surprised by its conclusions but also interested in them, he said.
“The actual data underlying this stuff is hard to dispute,” Dr. Clark said. “When people see the logic, they say ‘I don’t necessarily believe it, but it’s hard to dismiss.’ ”
Heat Waves Are Getting Longer
By ANDREW C. REVKIN, The New York Times, August 7, 2007
Researchers studying western European temperature records have found that the length of heat waves there has doubled since 1880, from 1.5 days to 3 days on average. They also say that the number of summer days that are far hotter than the average for a particular date has tripled. The team described its work in the current issue of the Journal of Geophysical Research-Atmospheres. The scientists, led by Paul M. Della-Marta of the University of Bern in Switzerland, said the findings supported the idea that global warming from human activities could be making Europe more prone to extreme conditions. They recommended that health agencies in the region work on ways to limit human health risks from summer heat.
This is one that I've noticed anecdotally. I have very fair skin and burn easily, but even after SPF 15, I don't notice much of a difference in protection.
Really? The Claim: With Sunscreens, High SPF Ratings Are Best
By ANAHAD O’CONNOR, The New York Times, August 7, 2007
THE FACTS
Everyone knows that an SPF rating of 60 provides double the protection of SPF 30 — or does it?
Studies over the years have shown that sunscreen with an SPF, or sun protection factor, of 30 blocks about 97 percent of ultraviolet rays. A rating of 15 means 93 percent of UV rays are blocked, and anything higher than 30 remains in the 97 or 98 percent range.
In 1999 the Food and Drug Administration recommended that sunscreens with an SPF higher than 30 be labeled “30+,” mostly to prevent people from developing a false sense of security that might lead them to spend more time in the sun.
What many people do not realize is that the amount of sunscreen applied plays an enormous role. A study in The British Journal of Dermatology this year found that applying less than two ounces over the entire body at one time can leave people with an SPF rating far lower than what is on the bottle. Some studies have shown that people typically apply just 10 percent of the amount recommended.
It is also important to look for sunscreens that protect against UVA and UVB radiation. SPF ratings apply only to UVB rays, and some sunscreens provide no protection at all against UVA rays, which penetrate the skin more deeply. For broad protection, look for sunscreens with avobenzene, zinc oxide or titanium dioxide, all of which block UVA.
THE BOTTOM LINE
Above SPF 30, the increased protection is minimal.
I just love Natalie Angier...
Basics: Its Poor Reputation Aside, Our Fat Is Doing Us a Favor
By NATALIE ANGIER, The New York Times, August 7, 2007
In this country, the most popular cosmetic surgery procedure is liposuction: doctors vacuum out something like two million pounds of fat from the thighs, bellies, buttocks, jowls and man-breasts of 325,000 people a year. What happens to all that extracted adipose tissue? It’s bagged and disposed of as medical waste; or maybe, given the recent news about socially contagious fat, it’s sent by FedEx to the patients’ old college chums. But one thing the fat surely is not, and that is given due thanks for serving as scapegoat, and for a job well done.
We are now in what feels like the 347th year of the fastidiously vilified “obesity epidemic.” Health officials repeatedly warn that everywhere in the world people are gaining too much weight and putting themselves at risk of diabetes, high blood pressure, heart disease and other obesity-linked illnesses, not to mention taking up more than their fair share of molded plastic subway seat.
It’s easy to fear and despise our body fat and to see it as an unnatural, inert, pointless counterpoint to all things phat and fabulous. Yet fat tissue is not the problem here, and to castigate fat for getting too big and to blame it for high blood pressure or a wheezing heart is like a heavy drinker blaming the liver for turning cirrhotic. Just as the lush’s liver was merely doing its hepatic best to detoxify the large quantities of liquor in which it was doused, and just as the alcoholic would have been far worse off had the liver not been playing Hepa-filter in the first place, so our fat tissue, by efficiently absorbing the excess packets of energy we put in our mouths, has our best interests at heart.
“Obesity is not due to any defect in adipose tissue per se; it’s an issue of energy balance,” said Bruce M. Spiegelman of the Dana-Farber Cancer Institute in Boston. If you are consuming too many calories relative to what you burn off, the body must cope with that energy surplus, he said, “and adipose tissue is the proper place for it.”
“If you had no fat cells, no adipose tissue, you’d still be out of energy balance, and you’d put the excess energy somewhere else,” he said, at which point really bad things can happen. Consider the lipodystrophy diseases, rare metabolic disorders in which the body lacks fat tissue and instead dumps its energy overruns in that jack-of-all-organs, the liver, causing extreme liver swelling, liver failure and sometimes liver-bearer death.
“Some adipose tissue is a good thing,” said Barbara Kahn, chief of the endocrinology, diabetes and metabolism division at Beth Israel Deaconess Medical Center, at Harvard.
Indeed, evolutionary biologists have proposed that our relative plumpness compared with our closest nonhuman kin, the chimpanzee, may help explain our relative braininess. Even a lean male athlete with a body fat content of 8 percent to 10 percent of total body mass (half the fat found on the average nonobese, non-Olympic American man) is still a few percentage points more marbled than a wild male chimpanzee, and scientists have suggested that our distinctive adipose stores help ensure that our big brains will be fed even when our cupboards go bare.
Scientists who study fat emphasize that its bland and amorphous appearance notwithstanding, our adipose depots represent highly specialized organs, as finely honed to the task of energy storage as muscle is built for flexing. Our body fat is made of some 40 billion fat cells, or adipocytes, and their supportive matrix, with most of the bulk stashed under the skin but also threaded viscerally, around and between other organs. Each fat cell is essentially a bouncing balloon filled with those greasy lipids we call triglycerides, three fatty acid chains of mostly carbons and hydrogens arrayed in high-energy configurations that explain why, gram for gram, dietary fat has more than twice the calories of meat or starch; and every fatty acid trio is tacked to a sugar-sweet glycerol frame.
In most body cells, the watery cytoplasm where the labor of proteins takes place accounts for maybe 70 percent of the cell’s volume, with another 10 percent given over to the nucleus, seat of the cell’s DNA. In a fat cell, by contrast, lipids are king, queen and bishop, and the checkerboard, too. They fill more than 95 percent of the adipocyte volume, crowding the cytoplasm with its proteins and the nucleus with its genes up against the cell wall in what Dr. Kahn calls “a crescent moon space.”
Yet for all its lipid density, the average fat cell is ever primed to hoard more, to take in more fatty acids and sugars from the blood and stitch them into triglyceride stores, and to swell to several times its cellular waistline of yore. Most weight that we gain and lose in life is the result of our existing fat cells growing and shrinking, absorbing and releasing energy-rich lipids as needed, depending on our diet and exercise regimens of the moment. But when exposed to chronic caloric overload, fat cells will initiate cell division to augment the supply; and because fat cells, like muscle cells, rarely turn over and die, those new lipidinous recruits will be your helpmeets for life.
Fat is no rutabaga. It is dynamic and mercantile, exchanging chemical signals with the brain, bones, gonads and immune system, and with every energy manager on the body’s long alimentary train.
“We used to think of an adipose cell as an inert storage depot,” Dr. Kahn said. “Now we appreciate that it is an endocrine organ,” in other words, an organ that like the thyroid or pancreas, secretes hormones to shape the behavior of other tissues far and wide. Squashed to the side a fat cell’s cytoplasm may be, but it nevertheless spins out a steady supply of at least 20 different hormones. Key among them is leptin, an essential player in reproduction. Scientists suspect that a girl enters puberty when her fat stores become sufficiently dense to begin releasing leptin, which signals the brain to set the pulsing axis of gonadal hormones in motion.
Fat also seems to know when it is getting out of hand, and it may resist new personal growth. Dr. Spiegelman and others have shown that with the onset of obesity — defined as 25 or more pounds above one’s ideal weight — the fat tissue starts releasing potent inflammatory hormones. That response is complex and harmful in the long run. But in the short term, said Dr. Spiegelman, “inflammation clearly has an anti-obesity effect, and it may be the body’s attempt to restrain further accumulation of adipose tissue.” The fat sizes up the risks and benefits, and it takes its fat chance.
I especially like her because she's an evolutionary psychologist without the determinism, unlike many others *cough*see below*cough* If you haven't read her book, Woman: An Intimate Geography you really should.
In Dusty Archives, a Theory of Affluence
By NICHOLAS WADE, The New York Times, August 7, 2007
For thousands of years, most people on earth lived in abject poverty, first as hunters and gatherers, then as peasants or laborers. But with the Industrial Revolution, some societies traded this ancient poverty for amazing affluence.
Historians and economists have long struggled to understand how this transition occurred and why it took place only in some countries. A scholar who has spent the last 20 years scanning medieval English archives has now emerged with startling answers for both questions.
Gregory Clark, an economic historian at the University of California, Davis, believes that the Industrial Revolution — the surge in economic growth that occurred first in England around 1800 — occurred because of a change in the nature of the human population. The change was one in which people gradually developed the strange new behaviors required to make a modern economy work. The middle-class values of nonviolence, literacy, long working hours and a willingness to save emerged only recently in human history, Dr. Clark argues.
Because they grew more common in the centuries before 1800, whether by cultural transmission or evolutionary adaptation, the English population at last became productive enough to escape from poverty, followed quickly by other countries with the same long agrarian past.
Dr. Clark’s ideas have been circulating in articles and manuscripts for several years and are to be published as a book next month, “A Farewell to Alms” (Princeton University Press). Economic historians have high praise for his thesis, though many disagree with parts of it.
“This is a great book and deserves attention,” said Philip Hoffman, a historian at the California Institute of Technology. He described it as “delightfully provocative” and a “real challenge” to the prevailing school of thought that it is institutions that shape economic history.
Samuel Bowles, an economist who studies cultural evolution at the Santa Fe Institute, said Dr. Clark’s work was “great historical sociology and, unlike the sociology of the past, is informed by modern economic theory.”
The basis of Dr. Clark’s work is his recovery of data from which he can reconstruct many features of the English economy from 1200 to 1800. From this data, he shows, far more clearly than has been possible before, that the economy was locked in a Malthusian trap _ — each time new technology increased the efficiency of production a little, the population grew, the extra mouths ate up the surplus, and average income fell back to its former level.
This income was pitifully low in terms of the amount of wheat it could buy. By 1790, the average person’s consumption in England was still just 2,322 calories a day, with the poor eating a mere 1,508. Living hunter-gatherer societies enjoy diets of 2,300 calories or more.
“Primitive man ate well compared with one of the richest societies in the world in 1800,” Dr. Clark observes.
The tendency of population to grow faster than the food supply, keeping most people at the edge of starvation, was described by Thomas Malthus in a 1798 book, “An Essay on the Principle of Population.” This Malthusian trap, Dr. Clark’s data show, governed the English economy from 1200 until the Industrial Revolution and has in his view probably constrained humankind throughout its existence. The only respite was during disasters like the Black Death, when population plummeted, and for several generations the survivors had more to eat.
Malthus’s book is well known because it gave Darwin the idea of natural selection. Reading of the struggle for existence that Malthus predicted, Darwin wrote in his autobiography, “It at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. ... Here then I had at last got a theory by which to work.”
Given that the English economy operated under Malthusian constraints, might it not have responded in some way to the forces of natural selection that Darwin had divined would flourish in such conditions? Dr. Clark started to wonder whether natural selection had indeed changed the nature of the population in some way and, if so, whether this might be the missing explanation for the Industrial Revolution.
The Industrial Revolution, the first escape from the Malthusian trap, occurred when the efficiency of production at last accelerated, growing fast enough to outpace population growth and allow average incomes to rise. Many explanations have been offered for this spurt in efficiency, some economic and some political, but none is fully satisfactory, historians say.
Dr. Clark’s first thought was that the population might have evolved greater resistance to disease. The idea came from Jared Diamond’s book “Guns, Germs and Steel,” which argues that Europeans were able to conquer other nations in part because of their greater immunity to disease.
In support of the disease-resistance idea, cities like London were so filthy and disease ridden that a third of their populations died off every generation, and the losses were restored by immigrants from the countryside. That suggested to Dr. Clark that the surviving population of England might be the descendants of peasants.
A way to test the idea, he realized, was through analysis of ancient wills, which might reveal a connection between wealth and the number of progeny. The wills did that, , but in quite the opposite direction to what he had expected.
Generation after generation, the rich had more surviving children than the poor, his research showed. That meant there must have been constant downward social mobility as the poor failed to reproduce themselves and the progeny of the rich took over their occupations. “The modern population of the English is largely descended from the economic upper classes of the Middle Ages,” he concluded.
As the progeny of the rich pervaded all levels of society, Dr. Clark considered, the behaviors that made for wealth could have spread with them. He has documented that several aspects of what might now be called middle-class values changed significantly from the days of hunter gatherer societies to 1800. Work hours increased, literacy and numeracy rose, and the level of interpersonal violence dropped.
Another significant change in behavior, Dr. Clark argues, was an increase in people’s preference for saving over instant consumption, which he sees reflected in the steady decline in interest rates from 1200 to 1800.
“Thrift, prudence, negotiation and hard work were becoming values for communities that previously had been spendthrift, impulsive, violent and leisure loving,” Dr. Clark writes.
Around 1790, a steady upward trend in production efficiency first emerges in the English economy. It was this significant acceleration in the rate of productivity growth that at last made possible England’s escape from the Malthusian trap and the emergence of the Industrial Revolution.
In the rest of Europe and East Asia, populations had also long been shaped by the Malthusian trap of their stable agrarian economies. Their workforces easily absorbed the new production technologies that appeared first in England.
It is puzzling that the Industrial Revolution did not occur first in the much larger populations of China or Japan. Dr. Clark has found data showing that their richer classes, the Samurai in Japan and the Qing dynasty in China, were surprisingly unfertile and so would have failed to generate the downward social mobility that spread production-oriented values in England.
After the Industrial Revolution, the gap in living standards between the richest and the poorest countries started to accelerate, from a wealth disparity of about 4 to 1 in 1800 to more than 50 to 1 today. Just as there is no agreed explanation for the Industrial Revolution, economists cannot account well for the divergence between rich and poor nations or they would have better remedies to offer.
Many commentators point to a failure of political and social institutions as the reason that poor countries remain poor. But the proposed medicine of institutional reform “has failed repeatedly to cure the patient,” Dr. Clark writes. He likens the “cult centers” of the World Bank and International Monetary Fund to prescientific physicians who prescribed bloodletting for ailments they did not understand.
If the Industrial Revolution was caused by changes in people’s behavior, then populations that have not had time to adapt to the Malthusian constraints of agrarian economies will not be able to achieve the same production efficiencies, his thesis implies.
Dr. Clark says the middle-class values needed for productivity could have been transmitted either culturally or genetically. But in some passages, he seems to lean toward evolution as the explanation. “Through the long agrarian passage leading up to the Industrial Revolution, man was becoming biologically more adapted to the modern economic world,” he writes. And, “The triumph of capitalism in the modern world thus may lie as much in our genes as in ideology or rationality.”
What was being inherited, in his view, was not greater intelligence — being a hunter in a foraging society requires considerably greater skill than the repetitive actions of an agricultural laborer. Rather, it was “a repertoire of skills and dispositions that were very different from those of the pre-agrarian world.”
Reaction to Dr. Clark’s thesis from other economic historians seems largely favorable, although few agree with all of it, and many are skeptical of the most novel part, his suggestion that evolutionary change is a factor to be considered in history.
Historians used to accept changes in people’s behavior as an explanation for economic events, like Max Weber’s thesis linking the rise of capitalism with Protestantism. But most have now swung to the economists’ view that all people are alike and will respond in the same way to the same incentives. Hence they seek to explain events like the Industrial Revolution in terms of changes in institutions, not people.
Dr. Clark’s view is that institutions and incentives have been much the same all along and explain very little, which is why there is so little agreement on the causes of the Industrial Revolution. In saying the answer lies in people’s behavior, he is asking his fellow economic historians to revert to a type of explanation they had mostly abandoned and in addition is evoking an idea that historians seldom consider as an explanatory variable, that of evolution.
Most historians have assumed that evolutionary change is too gradual to have affected human populations in the historical period. But geneticists, with information from the human genome now at their disposal, have begun to detect ever more recent instances of human evolutionary change like the spread of lactose tolerance in cattle-raising people of northern Europe just 5,000 years ago. A study in the current American Journal of Human Genetics finds evidence of natural selection at work in the population of Puerto Rico since 1513. So historians are likely to be more enthusiastic about the medieval economic data and elaborate time series that Dr. Clark has reconstructed than about his suggestion that people adapted to the Malthusian constraints of an agrarian society.
“He deserves kudos for assembling all this data,” said Dr. Hoffman, the Caltech historian, “but I don’t agree with his underlying argument.”
The decline in English interest rates, for example, could have been caused by the state’s providing better domestic security and enforcing property rights, Dr. Hoffman said, not by a change in people’s willingness to save, as Dr. Clark asserts.
The natural-selection part of Dr. Clark’s argument “is significantly weaker, and maybe just not necessary, if you can trace the changes in the institutions,” said Kenneth L. Pomeranz, a historian at the University of California, Irvine. In a recent book, “The Great Divergence,” Dr. Pomeranz argues that tapping new sources of energy like coal and bringing new land into cultivation, as in the North American colonies, were the productivity advances that pushed the old agrarian economies out of their Malthusian constraints.
Robert P. Brenner, a historian at the University of California, Los Angeles, said although there was no satisfactory explanation at present for why economic growth took off in Europe around 1800, he believed that institutional explanations would provide the answer and that Dr. Clark’s idea of genes for capitalist behavior was “quite a speculative leap.”
Dr. Bowles, the Santa Fe economist, said he was “not averse to the idea” that genetic transmission of capitalist values is important, but that the evidence for it was not yet there. “It’s just that we don’t have any idea what it is, and everything we look at ends up being awfully small,” he said. Tests of most social behaviors show they are very weakly heritable.
He also took issue with Dr. Clark’s suggestion that the unwillingness to postpone consumption, called time preference by economists, had changed in people over the centuries. “If I were as poor as the people who take out payday loans, I might also have a high time preference,” he said.
Dr. Clark said he set out to write his book 12 years ago on discovering that his undergraduates knew nothing about the history of Europe. His colleagues have been surprised by its conclusions but also interested in them, he said.
“The actual data underlying this stuff is hard to dispute,” Dr. Clark said. “When people see the logic, they say ‘I don’t necessarily believe it, but it’s hard to dismiss.’ ”
