2001 Science in Society Journalism Awards

Magazine

Gary Taubes

“The Soft Science of Dietary Fat”

NOTE: A .pdf version of “The Soft Science of Dietary Fat” is also available.

The reproduction of this article is intended for non-commercial, educational purposes only.

Part Four: Creating "consensus"

Once politicians, the press, and the public had decided dietary fat policy, the science was left to catch up. In the early 1970s, when NIH opted to forgo a $1 billion trial that might be definitive and instead fund a half-dozen studies at one-third the cost, everyone hoped these smaller trials would be sufficiently persuasive to conclude that low-fat diets prolong lives. The results were published between 1980 and 1984. Four of these trials — comparing heart disease rates and diet within Honolulu, Puerto Rico, Chicago, and Framingham — showed no evidence that men who ate less fat lived longer or had fewer heart attacks. A fifth trial, the Multiple Risk Factor Intervention Trial (MRFIT), cost $115 million and tried to amplify the subtle influences of diet on health by persuading subjects to avoid fat while simultaneously quitting smoking and taking medication for high blood pressure. That trial suggested, if anything, that eating less fat might shorten life. In each study, however, the investigators concluded that methodological flaws had led to the negative results. They did not, at least publicly, consider their results reason to lessen their belief in the evils of fat.

The sixth study was the $140 million Lipid Research Clinics (LRC) Coronary Primary Prevention Trial, led by NHLBI administrator Basil Rifkind and biochemist Daniel Steinberg of the University of California, San Diego. The LRC trial was a drug trial, not a diet trial, but the NHLBI heralded its outcome as the end of the dietary fat debate. In January 1984, LRC investigators reported that a medication called cholestyramine reduced cholesterol levels in men with abnormally high cholesterol levels and modestly reduced heart disease rates in the process. (The probability of suffering a heart attack during the seven-plus years of the study was reduced from 8.6% in the placebo group to 7.0%; the probability of dying from a heart attack dropped from 2.0% to 1.6%.) The investigators then concluded, without benefit of dietary data, that cholestyramine’s benefits could be extended to diet as well. And although the trial tested only middle-aged men with cholesterol levels higher than those of 95% of the population, they concluded that those benefits "could and should be extended to other age groups and women and ... other more modest elevations of cholesterol levels."

Why go so far? Rifkind says their logic was simple: For 20 years, he and his colleagues had argued that lowering cholesterol levels prevented heart attacks. They had spent enormous sums trying to prove it. They felt they could never actually demonstrate that low-fat diets prolonged lives — that would be too expensive, and MRFIT had failed — but now they had established a fundamental link in the causal chain, from lower cholesterol levels to cardiovascular health. With that, they could take the leap of faith from cholesterol-lowering drugs and health to cholesterol-lowering diet and health. And after all their effort, they were eager — not to mention urged by Congress — to render helpful advice. "There comes a point when, if you don’t make a decision, the consequences can be great as well," says Rifkind. "If you just allow Americans to keep on consuming 40% of calories from fat, there’s an outcome to that as well."

With the LRC results in press, the NHLBI launched what Levy called "a massive public health campaign." The media obligingly went along. Time, for instance, reported the LRC findings under the headline "Sorry, It’s True. Cholesterol really is a killer." The article about a drug trial began: "No whole milk. No butter. No fatty meats ..." Time followed up 3 months later with a cover story: "And Cholesterol and Now the Bad News. ..." The cover photo was a frowning face: a breakfast plate with two fried eggs as the eyes and a bacon strip for the mouth. Rifkind was quoted saying that their results "strongly indicate that the more you lower cholesterol and fat in your diet, the more you reduce your risk of heart disease," a statement that still lacked direct scientific support.

The following December, NIH effectively ended the debate with a "Consensus Conference." The idea of such a conference is that an expert panel, ideally unbiased, listens to 2 days of testimony and arrives at a conclusion with which everyone agrees. In this case, Rifkind chaired the planning committee, which chose his LRC co-investigator Steinberg to lead the expert panel. The 20 speakers did include a handful of skeptics — including Ahrens, for instance, and cardiologist Michael Oliver of Imperial College in London — who argued that it was unscientific to equate the effects of a drug with the effects of a diet. Steinberg’s panel members, however, as Oliver later complained in The Lancet, "were selected to include only experts who would, predictably, say that all levels of blood cholesterol in the United States are too high and should be lowered. And, of course, this is exactly what was said." Indeed, the conference report, written by Steinberg and his panel, revealed no evidence of discord. There was "no doubt," it concluded, that low-fat diets "will afford significant protection against coronary heart disease" to every American over 2 years old. The Consensus Conference officially gave the appearance of unanimity where none existed. After all, if there had been a true consensus, as Steinberg himself told Science, "you wouldn’t have had to have a consensus conference."

Science in Society Journalism Awards:
2009 | 2008 | 2007 | 2005 | 2004 | 2003 | 2002 | 2001 | 2000 | 1999 | 1998 | 1997 | 1996

Last revised: August 27, 2006

The National Association of Science Writers, Inc.
P.O. Box 7905, Berkeley, CA 94707 | (510) 647-9500