Time Magazine 1961. Ancel Keys appears on the cover to claim that saturated fat in the diet clogged arteries and caused heart disease.
Time Magazine, 2014. Eat Butter. Scientists were wrong about saturated fat. They don’t cause heart disease.
How did the low saturated fat message begin? How, when and why did this confusion begin?
Ancel Benjamin Keys was born in 1904 in Colorado Springs, Colorado to teenage parents. In his younger years he had various jobs including a clerk in a Woolworth store. He finished college in 3 years with Honors at Berkeley and earned a MS in Biology followed by a PhD from the Scripps Institute of Oceanography. In 1930 he traveled to Copenhagen to work with Nobel laureate, August Krogh where he studied the ability of eels to survive in both fresh and salt-water environments. He then went to Cambridge and obtained a second PhD in animal physiology from King’s College.
He married a biochemist, Margaret, in 1939 and established the Laboratory of Physiologic Hygiene at the University of Minnesota. It was this year that “he came to the attention of the United States War Department and was asked to develop and test food rations for parachute troops.” The result was the K ration, which became standard fare for feeding troops in World War II. Journal of Clinical Lipidology, (2011) 5, 434-437.
What made Keys famous was his Seven Countries Study, a study that remains controversial to this day. He initially observed that heart disease rates dropped in countries forced to alter their high fat diets because of the war rationing and reversed to higher rates when these diets returned.
He suspected dietary factors, particularly saturated fat, that might play a key role in atherosclerosis. After conducting some well-designed studies to support his theory, “he formulated an equation that simply showed a 2.7% mg/dl rise in cholesterol for every 1% of calories derived from saturated fat. The equation also suggested that polyunsaturated fat lowered serum cholesterol and dietary cholesterol raised serum cholesterol but to a lesser extent than saturated fat. “ Journal of Clinical Lipidology, page 435
Keys had based his theory on when he had previously visited Italy and Spain. He observed in Naples, Italy that only heart disease patients in hospitals were wealthy men. In Madrid, Spain he took blood samples from some men in one of the poorer districts where heart disease was rare and compared them to samples of more well-off patients with heart disease. What he found were differences in their serum cholesterol values with the higher levels in the wealthy and lower values in the poorer population. The diets of the two groups also differed with the poorer diets lower in fat than those of the wealthy. These observations were central to his theory that saturated fat or animal fat and dietary cholesterol contributed to heart disease. Levenstein, Harvey, Junk Science Week: Lipophobia and the Bad Science Diet, Financial Post, June 11,2012.
The theory gained some steam when in 1955, President Dwight David Eisenhower had a heart attack at age 64, “ Over the next six weeks, twice-daily press conferences were held on his condition. After his attack, he dieted religiously with a low-fat diet and had his cholesterol measured ten times a year (it had been 165 mg initially)”. Taubes, Gary. Good Calories, Bad Calories, page 1-4. The low-fat diet had little effect and his cholesterol continued to rise as well as his weight.
Between 1955 and 1958, Keys began to study the male population aged 40 to 59 in rural areas in certain countries. He used electrocardiograph data to detect heart abnormalities and cardiovascular disease. The countries included Yugoslavia, Italy, Greece, Finland, the Netherlands, the U.S. and Japan. The countries he had chosen represented varied intakes of saturated or animal fat; lower levels were found in some populations in Yugoslavia, Italy, Greece, and Japan. Finland, the Netherlands, and the U.S. represented higher levels of animal fat in their diets. Five and ten years later, the researchers returned to identify those who had experienced heart attacks. The lowest rates were found in Crete and Japan with the lowest levels of animal fat; the highest was found in East Finland and the U. S. with the highest levels of animal fat. All in all, Keys studied nearly 13,000 men. From this study, he concluded that “saturated fats as a percentage of calories was the most powerful lifestyle predictor of heart disease. “Blood cholesterol was the important physiological variable. “ Journal of Clinical Lipidology, page 437.
In 1961 Keys appeared on the cover of Time magaine with the Seven Countries Study’s alleged link between fat, cholesterol and heart disease that fueled the fear of dietary fat in America. Two weeks later the American Heart Association (AHA) endorsed the theory. With this announcement, the vegetable oil producers could not get their advertisements out fast enough. Wesson Oil said: “polyunsaturated Wesson is unsurpassed by any leading oil in its ability to reduce blood cholesterol.” Nutrition scientists jumped on the bandwagon. For example, Harvard nutritionist, Frederick Stare advised swallowing three tablespoons of polyunsaturated oil each day. Lipophobia had begun in earnest. Levenstein, Harvey, Lipophobia and the bad science.
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. Ironically, based on the thesis of Keys that saturated fat was the culprit, the AHA and other agencies had urged food processors to use trans fats to replace the alleged deadly saturated fat. Ironically, the most common source of trans fats turned out to be the very margarine they had promoted as heart healthy. From 1956 to 1976, per-capita butter consumption fell by over half.
Key’s hypothesis strengthened in 1977 with Senator George McGovern’s publication of the First Dietary Goals for the U.S., which was the first time that any government group had told Americans to eat less fat and cholesterol to improve health. The document became gospel and had a tremendous impact on consumers and the food industry. In 1980, Hegsted and McGinnis produced the USDA Dietary Guidelines for Americans that concurred with “avoiding too much fat and cholesterol and eating more foods with adequate starch and fiber.”
However, three major studies failed in their support for Key’s hypothesis and without going into the details, each one raised doubts about the hypothesis. The studies were the Women’s Health Initiative (WHI) in 1991, the Multiple Risk Factor Intervention Trial (MRFIT) in 1982, and the more recent LOOK AHEAD Study. Ironically in 1989, Frederick Stare from Harvard University, who had originally supported the Keys thesis, reversed his opinion and joined the opposite camp of doubters by co-authoring a book entitled Balanced Nutrition: Beyond the Cholesterol Scare.
The Key’s Seven Countries Study, so pivotal in lipophobia has been debunked by many, particularly those who favor the idea of eating meat.. On the other hand, vegans favor the thesis. Here is what the critics of the study say: First, Keys did not randomly choose countries but is accused of picking those countries most likely to support his theory. He excluded France whose diet has been notoriously rich in saturated fat along with a low heart disease rate (The French Paradox). He also excluded Switzerland, Sweden, and West Germany with the similar higher saturated fat intakes but with lower rates of heart disease. He originally gathered data from 22 countries. However, some point out that even when all 22 countries are analyzed, the trend that fat intake is associated with heart disease still weakly exists.
From his work with the GreeK islands, Crete and Corfu, Dr. Keys and his wife wrote two best-selling books, Eat Well and Stay Well and How to Eat Well and Stay Well the Mediterranean Way. These and a third book they wrote, “The Benevolent Bean,” had the kind of recipes on foods of the Mediterranean regions that Keys had studied. To their credit, their books were among the first extolling the virtues of the popular Mediterranean diet today. After living in Italy for many years and following his own advice, Ancel Keys died in November of 2004 at the age of 100 years old.
Key’s thesis is still hotly debated to this day because of its limitations and lack of conclusive support from the research community. There are still adherents of the efficacy of the low fat diet, particularly in its effects on atherosclerosis regression or prevention. The debate has now switched to which diet is heart healthy – a low-fat or a low-carbohydrate diet. However, that is another story.
I truly don’t know if Keys was right or wrong. The purpose of this post is to point out that his legacy remains as one of the leading food crusaders that changed the American plate. Is the low fat craze finally coming to an end? Has this national experiment failed? Will the low carbohydrate diet help curb the obesity epidemic or prevent heart disease? Sounds like a “soap opera, doesn’t it? One thing is certain – atherosclerosis is a complicated disorder and until its origin and pathology is conclusively determined, no one will know who was right.
As Keys himself summarizes: “The direct evidence on the effect of diet on human atherosclerosis is very little…. but such evidence as there is, plus valid inferences from indirect evidence, suggests that a substantial measure of control of the development of atherosclerosis in man may be achieved by control of the intake of calories and all kinds of fats, with no special attention to the cholesterol intake”. Human Atherosclerosis and the Diet, Ancel Keys, Circulation 1952; 5: 115-118.
According to David Katz. MD, Director, Yale University Prevention Research Center, “For whatever it is now worth, to my read, Keys’ messages were mostly right, a bit wrong and horribly vulnerable to the distortions of mercenary marketing and mass gullibility”. David Katz, MD, MPH The Keys to Good Health, August 14, 2014.