How a now-discredited diet theory became a national mania
By Harvey Levenstein
The most striking thing about North America’s fear of food is how markedly ideas about food’s healthfulness have changed over the years. Chemical preservatives went from being triumphs of modern science to poisons. Whole milk has swung back and forth like a pendulum. Yogurt experienced boom, bust and revival. Margarine went from “heart-healthy” to artery-clogging. And now we are told that salt, historically regarded as absolutely essential to human existence, is swinging the grim reaper’s scythe.
And then there’s the story of fat. One wonders what would have happened if the fats in our food and blood streams had been called by their scientific name, lipids. Would avoiding the off-putting term “fat,” with its connotation of obesity, have mitigated much of the fear of fats in food? Perhaps, but probably not. In retrospect, the wave of lipophobia — fear of dietary fat — that has swept over middle-class Americans since the 1950s was simply too powerful to overcome.
As with many other fears, fear of dietary fat originated in alarm over a supposed epidemic — in this case, of coronary heart disease. The best known advocate of this theory was Ancel Keys, a physiologist at the University of Minnesota in Minneapolis.After the Second World War, Keys became curious about something that kept cropping up in local newspapers. Many local business executives were being struck down with sudden heart attacks. The most likely cause of the attacks was smoking, but Keys wasn’t looking for that. He tested 286 middle-aged businessmen and found high levels of cholesterol in their blood. He soon concluded that this buildup of cholesterol was the main culprit in the businessmen’s heart attacks.
A few years later, in 1952, Keys found support for his theory on a visit to Naples, Italy. There, he was told that practically the only coronary patients in the city’s hospitals were rich men in private hospitals. (No one seems to have told him that poorer Italians, especially in the south, clung — often with good reason — to the old notion that few patients emerged from hospitals alive and avoided them at all costs.) Later that year, in Madrid, Keys took blood samples from some men in one of the city’s working-class quarters, where heart disease was also said to be rare. Then he did the same with 50 well-off patients of a prominent Spanish doctor who had told him that heart disease was rife among them. Lo and behold, the Naples firemen and poor people in Madrid had significantly lower levels of cholesterol in their blood than the wealthy madrileños, whose serum cholesterol levels were as high as those of the Minnesota businessmen.
To Keys, this seemed conclusive proof that high-fat diets caused high cholesterol in the blood, which in turn caused heart disease. Keys’s theory did have a sort of commonsensical appeal. It also made eminent sense to Dr. Paul Dudley White, America’s most prominent cardiologist. White, like Keyes, became convinced that the simple diets of Italians held the key to their immunity from the epidemic of heart attacks.
As president of the International Society of Cardiology, White was well-placed to spread the good word. In 1954, he turned the society’s international congress in Washington into a forum for research, with Keys’s theory at centre stage. In the inaugural session, White and Keys presented their argument to 1,200 doctors packed into a hall that sat 800.
They reported that in a hospital in southern Italy, where high-fat diets were rare, only 2% of the deaths were due to coronary causes, whereas in White’s hospital in Boston, it caused 20% of the deaths. He told Time magazine that “being overweight isn’t so much of a health problem as most people think…. Worrying about it can easily miss the real problem,” which was heart and artery problems caused by high-serum cholesterol.
The mainstream media rallied to Keys’s and White’s side. The New York Timesreported that specialists from around the world “agreed that high-fat diets, which are characteristic of rich nations, may be the scourge of Western civilization. The diets were linked with hardening and degeneration of the arteries.” Newsweek’s report was more direct. Fat’s the Villain was its headline, meaning dietary, not body, fat. Politics soon provided White and Keys with a golden chance to further publicize their message. Early in the morning of Sept. 24, 1955, 64-year-old president Dwight Eisenhower suffered a heart attack while staying at his mother-in-law’s home in Denver, Colo. With some fanfare, the air force flew White from Boston to the popular president’s bedside. White caused quite a stir at the first of his twice-daily press conferences by saying the president had just had a normal bowel movement — something not usually discussed in public.
Having caught the public’s attention, he then used the regular press conferences to warn Americans about “the disease that had become the great American epidemic.” After the president returned to the White House, White wrote a nationally syndicated newspaper article with his “reflections” on Eisenhower’s heart attack. He said that although the presidency was a highly stressful position, the clogging of the arteries that led to the heart attack had little to do with stress.
The day after White’s piece appeared, Time magazine featured Keys in a cover story on “the nation’s No. 1 killer,” heart disease. “Atherosclerosis,” it said, was “the real bugbear,” attacking the coronary arteries with special frequency.
Thanks in large part to White, Keys was able to gain government support for a far-ranging study designed to counter the objections to his theory. In the meantime, Keys and his wife wrote a diet book, Eat Well and Stay Well, to teach Americans how to reduce their cholesterol intake by cooking the kind of healthy food enjoyed by Mediterranean people like their neighbours in Naples.
The “chief reason” for the book, said Keys, was to wage war against cholesterol, and an initial chapter told of recently discovered differences in fats in a simple, straightforward fashion: “Hard” fats — such as butter, lard, cheese, and lard-based margarine — were “saturated” and caused high levels of cholesterol in the blood and “probably” deposits in the coronary arteries. On the other hand, fats that were liquid at room temperatures, such as corn and cottonseed oil, were “unsaturated” and were “to be favoured.”
This simple view of a “saturated/unsaturated fat” dichotomy allowed the Keyses to suggest a diet that was very easy to follow. Many of the recipes simply substituted skim milk for whole milk and vegetable oil for butter and lard. Because Keys thought that the “pre-formed” cholesterol in eggs and organ meats was not absorbed into the bloodstream, he saw no problem in eating three or four eggs a day. Nor did the book advise giving up red and fatty meats, whole chickens with skins, or Polish sausage.
In late December 1960, Keys received a boost when the American Heart Association had him draw up a statement that said reducing the amount of saturated fat in the diet was “a possible means of preventing atherosclerosis and decreasing the risk of heart attacks and strokes.” The AHA did force Keys to add that “as yet there is no final proof” of causality, but press reports on the statement quoted a former AHA president as saying that nine out of 10 doctors were already “going ahead on the assumption that there is a relationship and that it’s a good idea to trim cholesterol levels.”
Within hours, giant commercial interests were rolling out their artillery. Vegetable oil producers began vying over whose product was better at preventing heart attacks. Wesson Oil’s full-page ads quoted the AHA statement that substituting polyunsaturated fats for saturated fats reduced blood cholesterol and “hence the risk of heart attacks,” and said, “polyunsaturated Wesson is unsurpassed by any leading oil in its ability to reduce blood cholesterol.”
A week after the AHA statement, the lipophobe camp received another boost when Time magazine did a cover story on Keys. Titled Fat of the Land, it called him “the man most firmly at grips with the problem … of diet and health.” Said Time: “The main culprit” in causing “the nation’s No. 1 killer: coronary artery disease … was saturated fat in the diet, which raised levels of cholesterol in the blood…. He regards the cause-and-effect relationship between cholesterol and heart disease as proved.” Keys’s scientific opponents, for much of the 1960s, fought back doggedly, provoking what came to be called the “cholesterol wars.”
This revolved around two questions: First, do high levels of cholesterol in the blood cause heart attacks? Second, if this is true, can the high cholesterol levels be diminished by a low-fat diet? By 1970, much of the medical research establishment was on board with the first proposition. But proponents of the second — that it could be significantly lowered by diet — were finding conclusive proof elusive.
However, as far as the general public was concerned, both questions had been answered decisively in the Keysians’ favour. Indeed, they were assured of this by the nation’s most prominent nutritionists. In his syndicated column, Jean Mayer of Tufts University, the nation’s best-known nutritional scientist, warned that low-carbohydrate diets led to increased fat consumption, which was “the equivalent to mass murder.”
Equally important in the triumph of lipophobia was a new force in creating food scares: non-profit health advocacy groups. Often begun by well-meaning people seeking to raise money to cure diseases, they could easily mutate into slick machines staffed by professional fundraisers whose hefty salaries depended on alarming the public about the dangers posed by their particular illness.
This is exactly what happened to the American Heart Association (AHA). Originally formed in the 1920s by heart specialists to exchange ideas about their field, by 1945 it was raising a modest US$100,000 a year to subsidize conferences and fund some research. Meanwhile, the March of Dimes, founded in 1938 to combat polio, was collecting US$20-million annually. This could not have been far from the minds of the new leaders who took over the AHA and set out to arouse public concern about the “coronary plague.” They hired Rome Betts, a former fundraiser for the American Bible Society, to create a professional fundraising apparatus.
He recruited a star-studded cast of lay people, including the Hollywood movie mogul Sam Goldwyn and the author Clare Booth Luce, wife of the powerful Time-Life publisher Henry Luce, to sit on a new board of governors.
Another shot in the arm for Keys’s theory came from a more unlikely source, the American Medical Association (AMA). By 1960 large numbers of patients, and their doctors, were becoming convinced that reducing dietary cholesterol would head off heart attacks. This propelled the AMA into trying to assert control over the new therapy. It issued a report agreeing with that year’s American Heart Association statement that those at elevated risk for heart disease should eat less fat and replace saturated fats with polyunsaturated ones, but the doctors warned that this should only be done “under medical supervision.”
Vegetable oil and margarine producers quickly exploited the AMA’s consequent recommendation to replace butter and lard with vegetable oil. Nucoa and Fleischmann’s margarines each claimed to be the highest in healthy polyunsaturated fats. General Mills claimed that its “Saff-o- Life” safflower oil (an oil that had previously been used mainly in varnish, solvents and linoleum) had more polyunsaturated fats than any other oil. The major producer of safflower oil rushed out its own “Saffola” oil, whose ads began, “Read what the AMA says about the regulation of dietary fat.” Soon polyunsaturated oil was being touted as a health food in its own right. The Harvard nutritionist Frederick Stare advised swallowing three tablespoons of it each day as a “medication.” Jean Mayer, his counterpart at Tufts, said that consuming one cup of corn oil a day would prevent heart disease, but that it did not have to be in raw form.
From 1956 to 1976, per-capita butter consumption fell by over half and egg consumption dropped by over a quarter. Consumption of margarine doubled from 1950 to 1972 and that of vegetable oil rose by over 50% in the 10 years from 1966 to 1976.
Given the slow pace at which consumption of core foods in a national diet normally changes, these are very impressive statistics. In 1976 the lipophobes capped their apparent victory by bringing the U.S. government on their side. That year the Senate committee on nutrition began hearings on “Diet Related to Killer Diseases.” The committee chairman, Democratic senator George McGovern, was already a convert to the diet-heart theory, as was its senior Republican member, Charles Percy. The committee’s bias was revealed at the very outset, when it elicited testimony saying that an incredible 98.9% of the world’s nutrition researchers believed that there was a connection between blood cholesterol levels and heart disease.
After a mere two days of hearings, Nick Mottern, an ex–labour reporter with no scientific training who lionized Keys, was assigned to write up the committee’s report. The result, published early the next year as Dietary Goals for Americans, enshrined the diet-heart dogma into national nutrition policy. It called for Americans to increase their consumption of carbohydrates and to decrease their consumption of fats by 25%. Saturated fats were to be cut even more, by over one-third, mainly by cutting back on red meat.
In 1984, the National Institutes of Health, supported by the AHA, mounted a National Cholesterol Education Program to persuade Americans to drastically cut back on cholesterol, “a major cause of coronary heart disease.” In July 1988, the surgeon-general of the United States, C. Everett Koop, topped this by issuing a 700-page report that, in the words of yet another Time magazine cover story, “exhorts Americans to cut out the fat.” The president of the AHA said that if everyone went along with its recommendations, atherosclerosis would be “conquered” by 2000. Although it was now calculated that even a drastic reduction of dietary cholesterol would reduce the blood cholesterol levels of only about half of Americans, and then only by about 10%, the AHA and its allies continued to recommend low-fat diets for everyone.
In 1987 and 1988, the AHA and the National Academy of Sciences, the surgeon-general of the United States, the National Heart, Lung and Blood Institutes, the National Cancer Institute, the U.S. Department of Agriculture, the Centers for Disease Control, the AMA and the American Dietetic Association all “urged Americans from age two upward to go on restricted [low-fat] diets in the hope of preventing CHD [coronary heart disease.]” The AHA and the surgeon-general urged food processors to help out by producing more low-fat foods. In December 1988 Time magazine concluded another long cover story by quoting the president of the AHA as saying that “more than half the adult population” could reduce its chances of getting heart disease with low-fat diets. This included eating more low-fat foods, whose impact on heart disease would later be questioned.
By 1990, the repeated failure of studies trying to prove that saturated fat caused heart disease was beginning to cause defections from the lipophobe side. In 1989, Harvard’s Frederick Stare, who had enthusiastically supported Keys, reversed himself and co-authored a book denouncing the “cholesterol scare.” More challenges to lipophobia followed, culminating in 2006 with a massive study done as part of the NIH’s Women’s Health Initiative. It indicated that low-fat diets had no effect on rates of either cancer or cardiovascular disease among women.
The lipophobes, however, proved to be remarkably adept at bobbing, weaving and altering their message in the face of the challenges. The American Heart Association continued to find new ways to prosper from lipophobia. In 1988 it deleted the provision in its charter prohibiting product endorsements and began offering, for a fee, to endorse any food products that met its guidelines for fat, cholesterol and sodium. In final form, the AHA campaign sold the right to use a “Heart Check” symbol and say “Meets American Heart Association food criteria for saturated fat, cholesterol and whole grains for healthy people over age two.” For this, it charged fees ranging from the US$2,500 it cost Kellogg’s for each of the more than 50 of its products that qualified (including such nutritional dazzlers as Fruity Marshmallow Krispies) to the $200,000 that Florida citrus fruit producers paid for exclusive rights to the symbol, cutting out their competitors in California. The Florida producers now ran ads saying, “Fight Heart Disease. Drink Florida Grapefruit Juice.” In 1992–93 ConAgra, the hydra-headed giant involved in practically every stage of food production, gave $3.5-million to the AHA, ostensibly to make a television program on nutrition.
By the end of the 20th century, however, the AHA’s calls to reduce heart disease through diet were sounding rather threadbare. There was still no evidence that low-fat diets prevented heart disease. In 1996 the American College of Physicians came out against the AHA program of screening all people over 20 for high cholesterol. It said that it resulted in young people being put on low-fat diets that rarely reduced cholesterol. Others began pointing out that the AHA campaign to have people adopt low-fat, high-carbohydrate diets led to increased consumption of calorie-dense foods that contributed to obesity and diabetes, both of which were risk factors for cardiovascular disease. Then, in 2000, another fat panic gave lipophobia yet another boost. This time it was about trans fats, which were in the hydrogenated oils used in making everything from French fries to Doritos to granola bars.
New York City banned trans fats from restaurants, school boards across the nation banished them from cafeterias, and processors began furiously trying to replace them. One would think that the trans fat scare might prompt lipophobes to eat a bit of humble pie. After all, years before, when trans fat issues were first raised, Keys had dismissed these fears as groundless. Then, in the 1970s, the AHA, the Center for Science in the Public Interest, and other agencies had urged processors to use trans fats to replace supposedly deadly saturated fats. Moreover, the most common conveyor of trans fats to the bloodstream turned out to be margarine, which they all had recommended as a heart-healthy alternative to deadly butter.
Yet nary a mea culpa was heard.
But all the talk about “good” and “bad” fats finally forced lipophobes to abandon their calls for reducing total consumption of dietary fat. Instead, the AHA began recommending that people substitute unsaturated fats, such as olive oil, for the saturated and trans fat ones in their diets. Similarly, in 2000 the government’s revised Dietary Guidelines replaced the previous advice to choose a diet that was “low in fat, saturated fat and cholesterol” with a diet that was “low in saturated fat and cholesterol and moderate in total fat.”
But lipophobia remained. In 2000, the AHA had introduced a new “heart-healthy” diet that, like its older ones, recommended eating plenty of no-fat and low-fat foods to reduce cholesterol levels. It also continued to endorse “heart-healthy” low-fat foods to help them do so, collecting over $15-million for these endorsements in 2007. Yet by then, even lipophobic scientists were saying that it was cholesterol in the blood, not in the diet, “that counted.”
Then, in late 2008 came an apparently crushing scientific blow. A new theory claimed that the main culprit in heart disease was not fat, but inflammation. Statins were effective, it said, because they reduced levels of a protein, called high-sensitivity C-reactive protein (CRP), that contributes to inflammation in the body. The crucial risk factor for heart disease was therefore not cholesterol, but elevated CRP, which has nothing to do with fat in the diet.
In July 2009 another study tried to alter this theory by reducing CRP to the role of an indicator, not a cause, of heart disease. Inflammation remained a villain, but whether it was cause or effect was unknown.
With cholesterol’s role now unclear, it seemed highly unlikely that Keys’s diet-heart theory would ever be resurrected.
In February 2010, the press reported on a meta-analysis of 21 lengthy studies, comprising 347,747 subjects, that concluded that there was no association between saturated fat consumption and the risk of heart disease.
Excerpt adapted from “Fear of Food: A History of Why We Worry about What We Eat,” by Harvey Levenstein, published 2012 by University of Chicago Press.