"Eat food, not too much, mostly plants." The simplicity and accuracy of those words, written by Michael Pollan in his masterpiece In Defense of Food, are unmatched. But why are plant-based foods so Read
You would've had to live in a cave for the last 40 years to have missed the health memo that too many saturated fats, particularly from animal sources, are harmful to your health.
For example, a quick tour of the American Heart Association website indicates that saturated fats:
- raise blood cholesterol levels and risk of heart attack and stroke
- come mainly from animal sources such as meats, eggs and dairy
- should be limited to less than 7% of your daily caloric intake
- should be replaced with fish, nuts, beans, legumes and perhaps liquid vegetable oils.
Am I ever stepping on a bloggers' landmine now, but how did we learn that animal saturated fats were associated with heart disease? Isn’t heart disease—the number one killer of adults worldwide—just part of getting older, as was thought several generations ago?
Thanks to a medical researcher with one of the most amazing careers ever, we've been able to prove this link. Unfortunately, in the nine years since his death (at age 100!) he has become a target on the internet by people with none of his credentials.
Let me introduce you to Dr. Ancel Keys. (I don’t know how you indicate two PhDs, because Dr. Keys got one from Scripps and one from Cambridge.) Why was he considered a genius during his long life, but has been attacked on the internet since he died in 2004?
Before you choose between a black bean or beef burger, let’s review his life work.
After positions at Harvard, the Mayo Clinic, and the University of Minnesota, he was selected by the War Department to develop a reliable source of calories for soldiers at war against the Nazis. Ever heard of K-rations? The K is for "Keys," as he developed the small box of meat, cheese, biscuits, chocolate and candies, along with cigarettes. (It was the 1940’s and this was considered the healthy stuff.) Those K-rations provided a reliable 3,300 calories a day to American soldiers during the tough war years.
After the war, Dr. Keys was asked to study human starvation seen so commonly in WWII. In researching this, he observed that the number of heart attacks among European citizens fell in many countries during WW11. Was the wartime diet of largely plant-based foods low in animal fat (due to poverty and scarcity) actually good for heart heath? Dr. Keys developed a theory, called the diet-heart hypothesis, that food influenced the risk of heart disease, an idea that challenged the notion that heart disease was just an aging process.
He presented the hypothesis in 1955 using data from available sources derived from six countries with records indicating very different diets in terms of calories from fat (ranging from Japan at less than 10% of calories to the USA, with nearly 40% of calories from fat). This data showed that the more fat in the diet, the more deaths.
And guess what?
His ideas were attacked by colleagues who said it was not food. Two vocal critics (Yersuhalmy and Hilleboe) in 1957 presented their data from 22 countries, measured back in 1950, which showed the same relationship Keys reported but not quite as strong! What a critique! Their analysis actually went beyond Keys in suggesting that it was specifically animal fats and protein, not just total fat, that were linked to increased cardiac death. Vegetable fats and protein were associated with lower rates of cardiac death.
What did Professor Keys do in response to criticism? He planned the first international prospective evaluation of diet and death rates, using large teams of researchers visiting 16 communities in seven countries with very different dietary patterns. The teams measured details of diet, labs and even EKGs in originally healthy persons. The Seven Countries Study began in September, 1958 and published results in beginning in 1970 in over 12,000 subjects.
Papers published in peer-reviewed medical journals demonstrated that the diet-heart hypothesis was correct and that increasing percentages of calories from animal saturated fats and protein were associated with increasing death rates from heart disease. The American Heart Association diet guidelines used today are still Keys’ guidelines.
Was he done with his research?
No way. He became interested in the diet of the Italians in the early 1950s and saw very low death rates from heart disease. He was the first to describe the Mediterranean Diet, a lifestyle that is celebrated today as an excellent model for health.
The book he wrote with his wife, Eat Well and Stay Well, was the first of its kind and sold enough copies so that Keys was able to purchase a home in Italy. Perhaps that's why he lived to over 100!
Dr. Keys went on to grace the cover of Time Magazine and was called "Mr. Cholesterol" for his seminal observations on diet and heart health. Many university lectures and awards continue to be named in his honor.
While the dead can no longer answer their critics, his amazing research career speaks for itself and has been confirmed by multiple observations that diets rich in plants and low in animal fats are associated with the longest survival. In fact, a new peer-reviewed research study of over 1.3 million persons again confirmed the relationship of increasing meat consumption and increased death rates.
The next time you push your cart past the dairy and meat department of your local grocer to spend more time and money in the produce section, think for a moment of Dr. Ancel Keys, the man who stood up to criticism, did the hard work, and taught us so much about health.
Pick the black bean burger.
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