What if Fat Doesn't Make You Fat?
"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 Institute of Health (NIH) had begun advising every American old enough to walk to restrict fat intake, and ... 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. ... Finally, in June 1999, 11 years after the project began, the Surgeon General's Office circulated a letter ... explaining that the report would be killed.
"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.
"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. 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.
"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 chat the Food Guide Pyramid suggests be eaten copiously. "