You can read Rohit's commentary on the sociology/politics of knowledge production here: http://www.xent.com/pipermail/fork/2002-July/013378.html
More interesting is the link Rohit posted to the lengthier, more scientific discussion about the politics of medical/diet research here. Highly recommended: http://nasw.org/mem-maint/awards/01Taubesarticle1.html
Mainstream nutritional science has demonized dietary fat, yet 50 years and hundreds of millions of dollars of research have failed to prove that eating a low-fat diet will help you live longer
When the U.S. Surgeon General's Office set off in 1988 to write the definitive report on the dangers of dietary fat, the scientific task appeared straightforward. Four years earlier, the National Institutes of Health (NIH) had begun advising every American old enough to walk to restrict fat intake, and the president of the American Heart Association (AHA) had told Time magazine that if everyone went along, "we will have [atherosclerosis] conquered" by the year 2000. The Surgeon General's Office itself had just published its 700-page landmark "Report on Nutrition and Health," declaring fat the single most unwholesome component of the American diet.
All of this was apparently based on sound science. So the task before the project officer was merely to gather that science together in one volume, have it reviewed by a committee of experts, which had been promptly established, and publish it. The project did not go smoothly, however. Four project officers came and went over the next decade. "It consumed project officers," says Marion Nestle, who helped launch the project and now runs the nutrition and food studies department at New York University (NYU). Members of the oversight committee saw drafts of an early chapter or two, criticized them vigorously, and then saw little else.
Finally, in June 1999, 11 years after the project began, the Surgeon General's Office circulated a letter, authored by the last of the project officers, explaining that the report would be killed. There was no other public announcement and no press release. The letter explained that the relevant administrators "did not anticipate fully the magnitude of the additional external expertise and staff resources that would be needed." In other words, says Nestle, the subject matter "was too complicated." Bill Harlan, a member of the oversight committee and associate director of the Office of Disease Prevention at NIH, says "the report was initiated with a preconceived opinion of the conclusions," but the science behind those opinions was not holding up. "Clearly the thoughts of yesterday were not going to serve us very well."
During the past 30 years, the concept of eating healthy in America has become synonymous with avoiding dietary fat. The creation and marketing of reduced-fat food products has become big business; over 15,000 have appeared on supermarket shelves. Indeed, an entire research industry has arisen to create palatable nonfat fat substitutes, and the food industry now spends billions of dollars yearly selling the less-fat-is-good-health message. The government weighs in as well, with the U.S. Department of Agriculture's (USDA's) booklet on dietary guidelines, published every 5 years, and its ubiquitous Food Guide Pyramid, which recommends that fats and oils be eaten "sparingly." The low-fat gospel spreads farther by a kind of societal osmosis, continuously reinforced by physicians, nutritionists, journalists, health organizations, and consumer advocacy groups such as the Center for Science in the Public Interest, which refers to fat as this "greasy killer." "In America, we no longer fear God or the communists, but we fear fat," says David Kritchevsky of the Wistar Institute in Philadelphia, who in 1958 wrote the first textbook on cholesterol.
As the Surgeon General's Office discovered, however, the science of dietary fat is not nearly as simple as it once appeared. The proposition, now 50 years old, that dietary fat is a bane to health is based chiefly on the fact that fat, specifically the hard, saturated fat found primarily in meat and dairy products, elevates blood cholesterol levels. This in turn raises the likelihood that cholesterol will clog arteries, a condition known as atherosclerosis, which then increases risk of coronary artery disease, heart attack, and untimely death. By the 1970s, each individual step of this chain from fat to cholesterol to heart disease had been demonstrated beyond reasonable doubt, but the veracity of the chain as a whole has never been proven. In other words, despite decades of research, it is still a debatable proposition whether the consumption of saturated fats above recommended levels (step one in the chain) by anyone who's not already at high risk of heart disease will increase the likelihood of untimely death (outcome three). Nor have hundreds of millions of dollars in trials managed to generate compelling evidence that healthy individuals can extend their lives by more than a few weeks, if that, by eating less fat (see sidebar on p. 2538). To put it simply, the data remain ambiguous as to whether low-fat diets will benefit healthy Americans. Worse, the ubiquitous admonishments to reduce total fat intake have encouraged a shift to high-carbohydrate diets, which may be no better--and may even be worse--than high-fat diets.
Since the early 1970s, for instance, Americans' average fat intake has dropped from over 40% of total calories to 34%; average serum cholesterol levels have dropped as well. But no compelling evidence suggests that these decreases have improved health. Although heart disease death rates have dropped--and public health officials insist low-fat diets are partly responsible--the incidence of heart disease does not seem to be declining, as would be expected if lower fat diets made a difference. This was the conclusion, for instance, of a 10-year study of heart disease mortality published in The New England Journal of Medicine in 1998, which suggested that death rates are declining largely because doctors are treating the disease more successfully. AHA statistics agree: Between 1979 and 1996, the number of medical procedures for heart disease increased from 1.2 million to 5.4 million a year. "I don't consider that this disease category has disappeared or anything close to it," says one AHA statistician.
Meanwhile, obesity in America, which remained constant from the early 1960s through 1980, has surged upward since then--from 14% of the population to over 22%. Diabetes has increased apace. Both obesity and diabetes increase heart disease risk, which could explain why heart disease incidence is not decreasing. That this obesity epidemic occurred just as the government began bombarding Americans with the low-fat message suggests the possibility, however distant, that low-fat diets might have unintended consequences--among them, weight gain. "Most of us would have predicted that if we can get the population to change its fat intake, with its dense calories, we would see a reduction in weight," admits Harlan. "Instead, we see the exact opposite."
In the face of this uncertainty, skeptics and apostates have come along repeatedly, only to see their work almost religiously ignored as the mainstream medical community sought consensus on the evils of dietary fat. For 20 years, for instance, the Harvard School of Public Health has run the Nurses' Health Study and its two sequelae--the Health Professionals Follow-Up Study and the Nurses' Health Study II--accumulating over a decade of data on the diet and health of almost 300,000 Americans. The results suggest that total fat consumed has no relation to heart disease risk; that monounsaturated fats like olive oil lower risk; and that saturated fats are little worse, if at all, than the pasta and other carbohydrates that the Food Guide Pyramid suggests be eaten copiously. (The studies also suggest that trans fatty acids are unhealthful. These are the fats in margarine, for instance, and are what many Americans started eating when they were told that the saturated fats in butter might kill them.) Harvard epidemiologist Walter Willett, spokesperson for the Nurses' Health Study, points out that NIH has spent over $100 million on the three studies and yet not one government agency has changed its primary guidelines to fit these particular data. "Scandalous," says Willett. "They say, 'You really need a high level of proof to change the recommendations,' which is ironic, because they never had a high level of proof to set them."
Indeed, the history of the national conviction that dietary fat is deadly, and its evolution from hypothesis to dogma, is one in which politicians, bureaucrats, the media, and the public have played as large a role as the scientists and the science. It's a story of what can happen when the demands of public health policy--and the demands of the public for simple advice--run up against the confusing ambiguity of real science.
rohit also points to the subtle shifts the article makes as it moves from one audience to another:
http://www.sciencemag.org/cgi/content/summary/291/5513/2536
vs. http://www.nytimes.com/2002/07/07/magazine/07FAT.html
vs. http://atkinscenter.com/Archive/2002/1/11-255043.html