For over 50 years, we have been told that a low-fat diet is the key to improving health, losing weight and preventing heart disease. Not so fast, says Nina Teicholz, author of The Big Fat Surprise. This information was not based on sound science and should not be taken without the proverbial grain of salt.
Instructions to lower fat and dietary cholesterol came at a time when Americans were reeling from far too many heart attack deaths among middle aged men, more than the country had seen before. In September 1955 came the most public heart attack of all, that of President Eisenhower.
The president’s physician, Paul Dudley Wright, was well aware of the heart disease crisis before it struck its most famous victim. Wright was a founding member of the fledgling American Heart Association (AHA). The organization was scarcely more than 30 years old at the time, founded at the beginning of physicians’ awareness of the crisis.
The American public, however, was not yet aware of the widespread nature of heart disease. They knew men around them who had died, but didn’t know that this was a national trend. With Eisenhower’s heart attack, that changed, as Nina Teicholz told Jane Black, who interviewed her for Elle magazine. They learned that, nationally, 40 percent of the deaths of middle aged men were from heart disease. And they wanted to know what could be done.
Wright believed he knew what that was. He was familiar with the diet-heart hypothesis of Ancel Benjamin Keys, a pathologist from the University of Minnesota. Keys’ hypothesis stated that a diet high in saturated fats and dietary cholesterol was the component that was causing the epidemic. Following Keys’ advice, Wright prescribed the president a low-fat diet as part of his plan to save him from continuing heart disease.
In The Big Fat Surprise, Nina Teicholz describes Keys as a scientist seeking to prevent disease. When interviewed for the MSNBC program Weekends with Alex, she said that Keys was responding to the same crisis that the rest of the country was experiencing. However, his good intentions at finding an answer did not make up for the mistakes he made scientifically as he searched for findings to support his theory. Along the way, he lost his objectivity and saw only data that would back up his claims that a low-fat diet was the only way to good heart health.
Already in 1955, Keys had been challenged to produce evidence of this theory by Sir George Pickering at the World Health Organization (WHO). He was unable to do so because he had stopped at the theory proposal step of the scientific method. He had gathered some data but had not yet scientifically tested his hypothesis. Challenged to do so, he developed his Seven Countries Study.
The study came from Keys’ experience as he traveled worldwide during the early 1950s examining in a cursory way the health and diets of men from various parts of Europe, Africa, Asia and the United States. He and his wife collected cholesterol and diet data from a small number of men wherever they went, and despite no scientifically recorded evidence, he proclaimed that the men’s saturated fat intake was the clear factor in their evidence of heart disease or lack thereof.
Not all of the countries that Keys visited neatly fit into his diet-heart hypothesis, however. Nina Teicholz explains in The Big Fat Surprise that one critic accused Keys of only discussing the countries that fit the mold he had made. Jacob Yerushalmy, the founder of the Biostatistics Department at the University of California, Berkeley, had also heard Keys speak at the WHO in 1955. He, like Pickering, took exception to the presentation of the theory with no scientific basis. In fact, he accused Keys of ignoring countries like France and Switzerland where diets high in saturated fat had not produced an abundance of heart disease patients.
This would not be the end of the bad science, as Teicholz explained in a 2014 feature article for the Independent. The Seven Countries Study that Keys launched next was rife with inconsistencies and poor scientific choices. First, looking at seven countries should have resulted in a widespread and worldwide sample. However, Keys handpicked his seven countries from areas he had already tested. He chose the ones that best fit his hypothesis. Second, the number of men was small by the standards of sampling populations. In the five countries, he only sampled 500 men. A third flaw, and perhaps the worst of all, was that Keys did not carefully weigh other factors in his diet study. For example, in one of the weeks of testing on the Isle of Crete, he surveyed the men’s eating habits during Lent. This was a time when the predominantly Greek Orthodox population was fasting from animal products anyway. What they were eating that week was in no way indicative of their typical diet.
A sign of good scientific practice is the willingness to see the outliers, the data that does not match the hypothesis that you are exploring. This openness to other possible answers to a problem makes true scientific discovery possible. Keys showed his unwillingness to participate in this type of questioning with his choices of countries to study in the Seven Countries Study. He also showed it by ignoring the studies of others.
One of these was the observations and experience of Arctic explorer Vilhjalmur Stefansson. Though his explorations were not always successful, he contributed to the field of nutrition science in an unexpected way. Early in The Big Fat Surprise, Teicholz records his findings as he lived among the Inuit in the Arctic.
While living there, Stefansson discovered that the typical Inuit diet was 70 percent fat and that they were very healthy living that way. He decided to adopt their way of eating himself. To his surprise, he was thriving after his time with them.
He and his colleague, Dr. Karsten Anderson, were so sure that they had discovered a previously unknown idea about nutrition that they submitted themselves to a year-long study begun at New York’s Bellevue Hospital. The two men ate a meat-only diet, submitting to medical testing and supervision along the way. Not only was their diet meat, it was fatty meat like that consumed by the Inuit. They exited the study healthy and fit.
This experiment was far from a sweeping scientific study, but it and other observations should have been enough to persuade Keys and his proponents to take another look at their claim that saturated fats are the prime cause of heart disease.
Another study of indigenous people that does not support the diet-heart hypothesis is that of George V. Mann, a physician and biochemistry professor. His subjects were men of the Masai tribe of Kenya. He began his study after he saw that the diet and health of the Masai did not support the declaration of the diet-heart hypothesis.
The Masai consumed three to five liters of milk daily and supplemented this with blood in the dry season. Whenever possible, they also consumed beef, lamb or goat. At times, they would eat as much as four to ten pounds of fatty beef in one day. Despite this diet that should have meant poor health by Keys’ standards, the men’s health was excellent. Mann studied electrocardiograms of 400 of the Masai men and found no evidence of heart disease. He also conducted autopsies on 50 men and found no evidence of cancer or diabetes.
Nina Teicholz discussed Mann’s findings in her TEDxEast talk in 2014, explaining that Mann even took the further step of exploring whether the Masai were somehow genetically predisposed to their particular high-fat diet. He studied members of the tribe that moved to Nairobi. As they adapted to a lower fat and higher carbohydrate diet in the city, they became heavier and less healthy. This was, Nina Teicholz said, reason to suspect that a diet low in fat is not the answer to good health.
Keys was never dissuaded of his poorly founded faith in the low-fat diet’s benefits to health. And he convinced many other people as well. The AHA issued the first-ever dietary guidelines in 1961. They followed Keys’ ideas to the letter. As Nina Teicholz writes in The Big Fat Surprise, “The AHA alone was like an ocean liner steaming the diet-heart hypothesis forward.” With Keys and his ally, Jeremiah Stamler, on the nutrition committee, they made widespread the advice that White, Eisenhower’s physician, had announced to the nation a few years before as his prescription for the president. A “prudent” diet for middle aged men to avoid heart attacks, they said, was one low in saturated fats and dietary cholesterol.
In The Big Fat Surprise, Nina Teicholz examines this and other shaky evidence that led to our current obsession with low-fat, low-cholesterol eating. She concludes that her subtitle is true: butter, meat and cheese do belong in a healthy diet.