The failure of the low-fat, high-carb American diet

By Louisa Enright | Jul 17, 2010
Louisa Enright

When Luise Light and her team of experts attempted to scientifically formulate the 1980 USDA Food Guide, they accepted two current dietary ideas: fat should be no more than 30 percent of the diet, and since the end of World War II, and especially in the 1960s, Americans had been experiencing "rising rates of heart disease, high blood pressure, stroke, and diabetes.

Current historians show us that the low-fat premise that has governed the American diet for the past 50 years sprang from belief, not science. Low-fat became part of American cultural and economic practices when the stars aligned around a constellation that included the political power of a congressional committee, media acceptance of its recommendations, and the beliefs of a handful of people.

Science writer Gary Taubes, in "The Soft Science of Dietary Fat," published in "Science" magazine in 2001, questioned the idea that there ever was an epidemic of heart disease after World War II. When Taubes interviewed Harry Rosenberg, Director of the National Center for Health Statistics, Rosenberg said in 1949 the International Classification of Diseases (ICD) added arteriosclerotic heart disease as a new category under the general category of heart diseases. Between 1948 and 1949, the new category appeared to raise coronary disease death rates about 20 percent for males and 35 percent for females.

Again, in 1965, the ICD added a category for coronary heart disease, which added more deaths to the statistical data. Furthermore, Rosenberg explained, by the 1950s, Americans were healthier, so more were living to be 50 year-olds, who would go on to die of chronic diseases like heart disease. Taubes reports that Rosenberg said that, in actuality, risk rates of dying from a heart attack remained unchanged.

Taubes also discussed the fact that between 1989 and 1992, three independent research groups (Harvard Medical School; The University of California, San Francisco, funded by the U.S. Surgeon General's Office; and McGill University, Montreal) used computer models to work out added life expectancy for a person eating a low-fat diet that controlled saturated fats. All three models agreed, but media has never discussed their conclusions. The Harvard study showed that if a person's total fat consumption was less than 30 percent of their daily total calories and if their saturated fat consumption was 10 percent of that 30 percent, a healthy nonsmoker might add from three days to three months of life.

The latter two studies showed the net increase of life expectancy would be from three to four months. Taubes noted that the U.S. Surgeon General's office tried to prevent the University of California study from being published in "The Journal of the American Medical Association, but JAMA published it in June 1991.


Lipid hypothesis

The Lipid Hypothesis is the "scientific" paradigm calling for a low-fat diet. The Lipid Hypothesis is the premise that ingested fat, especially saturated fat, raises blood cholesterol levels, and high cholesterol levels cause chronic heart disease. Yet, many, many scientists now have argued that these cause-and-effect links have never been proven and, in fact, cannot be proven. More recently than Taubes, Michael Pollan, in "In Defense of Food", covers "The Melting of the Lipid Hypothesis."

So how did the Lipid Hypothesis and the low-fat paradigm get installed with scant scientific data to support it?

Biochemist Ancel Keys is a key player. In the mid 1950s, Keys claimed that his epidemiological Seven Countries Study showed a correlation between the consumption of dietary fat and heart disease. But, an epidemiological study cannot control or eliminate variables, and correlation is not proved causation. Furthermore, many now, among them Taubes and Uffe Ravnskov, claim that Keys eliminated countries whose statistics did not fit his hypotheses, countries such as France, Holland, Switzerland, Norway, Denmark, Sweden, and West Germany, where national populations ate 30 to 40 percent of their calories as fat and whose death rates from chronic heart disease were half that of the United States. Nevertheless, in 1961, the American Heart Association began advocating low-fat diets for men with high cholesterol levels.

Also in the 1950s, Nathan Pritkin, was diagnosed with heart disease. Though he had no college degree and no scientific training, Pritkin created and published a low-fat, aerobic exercise regime that sold millions of copies.

In 1977, the Congressional Select Committee on Nutrition and Human Needs, chaired by Senator George McGovern, promoted the low-fat hypothesis-despite objections by scientists expert in the field. Taubes determines that "a handful of McGovern staffers... almost single-handedly changed nutritional policy in this country" by initiating "the process of turning the dietary fat hypothesis into dogma."

In 1976, Taubes reports, after two days of testimony, this committee turned "the task of researching and writing the first 'Dietary Goals for the United States'" over to Nick Mottern, a labor reporter with "no experience writing about science, nutrition, or health." Mottern relied on Harvard School of Public Health nutritionist Mark Hegsted's low-fat beliefs. Hegsted, unlike E. H. Ahrens, whose laboratory at the Rockefeller University in New York City was doing seminal research on fat and cholesterol metabolism, saw no risks associated with such a major change to the American diet. Ahrens, as early as 1969, was concerned that eating less fat or changing the proportions of saturated to unsaturated fats could have profound and harmful effects on the body. Nevertheless, the Select Committee published Mottern's dietary guidelines.

Next, Taube relates, Carol Tucker Foreman, a political appointee at USDA who later formed a public relations and lobbying firm whose clients have included Phillip Morris, Monsanto (bovine growth hormone), and Procter and Gamble (fake fat Olestra), hired Hegsted to produce "Using the Dietary Guidelines for Americans," which supported the McGovern Committee Report. Foreman hired Hegsted despite the fact that Philip Handler, National Academy of Sciences (NAS) President and an expert on metabolism, had told her that Mottern's Dietary Goals were "nonsense."

When NAS released its own dietary guidelines a few months later (watch your weight and everything else will be all right), the media criticized the NAS for having industry connections. Hegsted later returned to Harvard where his research was funded by Frito-Lay.

So, a consensus was achieved, one Taube says is "continuously reinforced by physicians, nutritionists, journalists, health organizations, and consumer advocacy groups such as the Center for Science in the Public Interest." And, science was "left to catch up."

Only, science never has. And, what has emerged is that all calories are not equal and substituting carbohydrates for fat has caused weight gain and diabetes. And, according to lipid biochemist Mary Enig, substituting highly-processed fats for time-honored, traditional fats is causing chronic heart disease.

Pollan notes that in a 2001 review of the relevant research and report by "prominent nutrition scientists" at the Harvard School of Public Health, "just about every strut supporting the theory that dietary fat causes heart disease" was removed, except for consuming trans fats and for consuming fats that alter ratios of omega 3 to omega 6 fatty acids. Pollan notes the Harvard scientists stated the following in their report's second paragraph: "It is now increasingly recognized that the low-fat campaign has been based on little scientific evidence and may have caused unintended health consequences."

Pollan assesses that the low-fat ideology of nutritionism has been nutrition's "supreme test and, as now is coming clear, its most abject failure."





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