Sally Squire's critical Washington Post piece of Taubes' NYT article "What If Its All Been a Big Fat Lie?" was succinctly answered by Taubes, below. Enjoy. It is a good example of how the media, when it has an agenda to push, can easily mislead and deceive the public.
Dietary Fat, Cont'd.
Sally Squires's Aug. 27 article ("What If the Big Fat Story Is Wrong?") claims to take a "hard look" at my July 7 New York Times Magazine article ("What If It's All Been a Big Fat Lie?") but instead misrepresents my article and my reporting and misinterprets the relevant science and medicine. While it's impossible in limited space to rectify all the copious misrepresentations in her story, the following clarifies key issues.
My NYT article questioned the common belief that obesity is caused by excess calorie consumption from fat, and instead suggested an alternative hypothesis: "It's not the fat that makes us fat, but the carbohydrates." It noted that low-fat diets are invariably high in carbohydrates -- typically refined carbohydrates and starches -- and that since the U.S. government began pushing low-fat diets in 1977, we have witnessed significant increases in consumption of grain products and sugars, significant increases in obesity and type 2 diabetes, and no decrease in heart disease. It questioned whether all this was coincidence or cause and effect.
My primary disagreement with Squires and public health authorities such as National, Heart, Lung, and Blood Institute director Claude Lenfant arises from our divergent views of how good science is done. Squires and the public health establishment act as if reliable knowledge is established by proving the validity of hypotheses, and that this is accomplished by accumulating all positive evidence supporting the hypotheses and rejecting all non-supportive, negative evidence. I side with Francis Bacon and Carl Popper, who argued that reliable knowledge comes by rigorously testing hypothesis, and that such tests require more weight be given to negative evidence than to positive evidence. My NYT article noted that copious evidence exists in contradiction to the low-fat-is-good-health hypothesis, while the alternative hypothesis may fit the data better but has never been adequately tested.
Moreover, Squires apparently believes that learned expert committees and government agencies are incapable of arriving at biased and incorrect conclusions on subjects of national importance, or at least on this particular subject. I believe they can and, in this case, that they probably did.
Squires faults me for ignoring "high-quality," "significant and well-known peer reviewed research," including the 2000 Report of the Dietary Guidelines Advisory Committee (DGAC). The report cites "many years of epidemiological research" supporting the dangers of saturated fats, although the one relevant article both it and Squires discuss in detail was not published in a peer-reviewed journal, begging the question of whether it constitutes "high-quality research." This in turn raises the question: If there is so much significant high-quality research out there, why do the DGAC and Squires rely on non-peer-reviewed literature to make their case?
Squires describes one of my "key assertions" as suggesting "that eating saturated fat can be beneficial to the heart." This is incorrect. The article said "saturated fats are not nearly as deleterious as you would think," and that lard, for instance, has more "good fats" -- monounsaturated and polyunsaturated -- than "bad fats" -- saturated. Thus, the overall effect on cholesterol profiles of eating lard rather than refined carbohydrates or starches would be at worst harmless. Squires quotes my article, but changes the meaning by eliding key phrases and replacing them with ellipses. She then describes Walter Willett as disagreeing with my assessment, which is only true if you delete what Squires indeed did delete from the quote.
Squires says I reject the findings of The 1998 Clinical Guidelines on the Identification, Evaluation and Treatment of Overweight and Obesity in Adults, due to my "negative personal assessment of the panel's chair." This is incorrect. Nor do I reject the findings. The report actually concludes that low-fat diets do not work. It says reducing calories is crucial to successful weight loss, something we both agree on, then says on page 95 in English "Reducing dietary fat alone without reducing calories is not sufficient for weight loss. However, reducing dietary fat, along with reducing dietary carbohydrates can facilitate caloric reduction."
Squires says I disagree with the findings of the Diabetes Prevention Study. This is incorrect. I disagree with Squires's interpretation of the findings: that the DPP data are compelling evidence for the efficacy of low-fat diets. The DPP reported that low-fat low-calorie diets and 150 minutes of weekly exercise produced a 5 percent to 7 percent weight-loss (15 to 21 pounds for a 300-pounder) over six years. Because the study included no control group for the dietary arm, for all we know exercise and a low-carbohydrate low-calorie diet might have produced much greater weight loss. Implying that this data confirms the efficacy of a low-fat diet is sophistic. Passing this kind of sophistry off as good science is common in this field and its media coverage and is regrettable.
Finally, Squires reports my skepticism of research by Dr. Richard Fleming without giving the context. As I explained at length to Squires, clinical trials are expensive, difficult and time-consuming. Even small dietary trials can easily cost several hundred thousand dollars and require entire research teams. The DPP estimated a cost of $1,075 just to recruit each participant.
Fleming reports on a one-year trial of 100 participants and four diets with extensive follow-up. His paper, however, has no co-authors; it acknowledges no source of funding, nor any nurses, dietitians or technicians who might have helped. Fleming identifies himself as Medical Director of Preventive Cardiology, the Camelot Foundation at the Fleming Heart & Health Institute, but if his Web site or receptionist are any indication, he is the sole member of each of those.
As for the issue of peer-review, Fleming states that his patients "were randomly assigned to one of the four dietary regimens based upon dietary preferences." This protocol is pivotal to interpretation of the findings, yet oxymoronic: If patients were assigned to diets based on their dietary preferences, then they weren't randomly assigned. If they were randomly assigned, then their preferences must be irrelevant. The two methods are incompatible. If this paper was peer-reviewed, it was done poorly. If this constitutes high-quality research in this field, then I suggest even more skepticism is necessary.
© 2002 The Washington Post Company