Good Calories, Bad Calories

Other factors were also pushing the public toward a belief in the evils of dietary fat and cholesterol that the medical-research community itself still considered questionable. The American Heart Association revised its dietary recommendations every two to three years and, with each revision, made its advice to eat less fat increasingly unconditional. By 1970, this prescription applied not just to those high-risk men who had already had heart attacks or had high cholesterol or smoked, but to everyone, “including infants, children, adolescents, pregnant and lactating women, and older persons.” Meanwhile, the press and the public came to view the AHA as the primary source of expert information on the issue.

The AHA had an important ally in the vegetable-oil and margarine manufacturers. As early as 1957, the year Americans first purchased more margarine than butter, Mazola corn oil was being pitched to the public with a “Listen to Your Heart” campaign; the polyunsaturated fats of corn oil would lower cholesterol and so prevent heart attacks, it was said. Corn Products Company, the makers of Mazola, and Standard Brands, producers of Fleischmann’s margarine, both initiated programs to educate doctors to the benefits of polyunsaturated fats, with the implicit assumption that the physicians would pass the news on to their patients. Corn Products Company collaborated directly with the AHA on releasing a “risk handbook” for physicians, and with Pocket Books to publish the revised version, in 1966, of Jeremiah Stamler’s book Your Heart Has Nine Lives. By then, ads for these polyunsaturated oils and margarines needed only to point out that the products were low in saturated fat and low-cholesterol, and this would serve to communicate and reinforce the heart-healthy message.

This alliance between the AHA and the makers of vegetable oils and margarines dissolved in the early 1970s, with reports suggesting that polyunsaturated fats can cause cancer in laboratory animals. This was problematic to Keys’s hypothesis, because the studies that had given some indication that cholesterol-lowering was good for the heart—Seymour Dayton’s VA Hospital trial and the Helsinki Mental Hospital Study—had done so precisely by replacing saturated fats in the diet with polyunsaturated fats. Public-health authorities concerned with our cholesterol dealt with the problem by advising that we simply eat less fat and less saturated fat, even though only two studies had ever tested the effect of such low-fat diets on heart disease, and they had been contradictory.

It’s possible to point to a single day when the controversy was shifted irrevocably in favor of Keys’s hypothesis—Friday, January 14, 1977, when Senator George McGovern announced the publication of the first Dietary Goals for the United States. The document was “the first comprehensive statement by any branch of the Federal Government on risk factors in the American diet,” said McGovern.

This was the first time that any government institution (as opposed to private groups like the AHA) had told Americans they could improve their health by eating less fat. In so doing, Dietary Goals sparked a chain reaction of dietary advice from government agencies and the press that reverberates still, and the document itself became gospel. It is hard to overstate its impact. Dietary Goals took a grab bag of ambiguous studies and speculation, acknowledged that the claims were scientifically contentious, and then officially bestowed on one interpretation the aura of established fact. “Premature or not,” as Jane Brody of the New York Times wrote in 1981, “the Dietary Goals are beginning to reshape the nutritional philosophy of America, if not yet the eating habits of most Americans.”

The document was the product of McGovern’s Senate Select Committee on Nutrition and Human Needs, a bipartisan nonlegislative committee that had been formed in 1968 with a mandate to wipe out malnutrition in America. Over the next five years, McGovern and his colleagues—among them, many of the most prominent politicians in the country, including Ted Kennedy, Charles Percy, Bob Dole, and Hubert Humphrey—instituted a series of landmark federal food-assistance programs. Buoyed by their success fighting malnutrition, the committee members turned to the link between diet and chronic disease.