Ancel Keys

Ancel Keys is one of the most polarizing figures in nutrition history, and he is the man who invented today's equally vivid fear of fat, and the belief that we must avoid eating fat at all costs. Saturated fat in particular became a villain, even though there have been studies that clearly show that it appears healthy, on the contrary.

The Sydney studyand The Minnesota Study are examples of studies that were hidden away for decades.

The story of his own “Seven Countries Study” is both fascinating and controversial. It provides insight into how science and politics can be intertwined in ways that have enormous influence on society’s health and diet.

A scientist who shaped nutritional science

Ancel Keys began his academic career studying physiology and first became known through his work during World War II, where he developed "The K-ration» to provide soldiers with nutritious and portable meals in the field. After the war, he shifted his focus to cardiovascular disease, which at the time was an emerging health crisis in the United States.

An important part of his early research was on hunger. His Minnesota Starvation Experiment in the 1940s was an attempt to understand the effects of starvation on the body and mind, and how to help starving people recover, especially after the war. This experiment made him famous in scientific circles, but it was his later work on diet and heart health that truly changed the way the world thinks about food.

"The Seven Countries Study": A selective hypothesis

In the 1950s and 60s, Keys developed his "diet-heart" hypothesis, which claimed that saturated fat increased cholesterol levels, which in turn led to cardiovascular disease.

This hypothesis became the basis for his infamous Seven Countries Study.

The problem wasn't that he collected data, but how he interpreted and presented it. Keys had access to extensive data from many countries, including places like France and Germany, where people had high fat intakes but low rates of heart disease.

These data did not support his hypothesis and were therefore omitted from the study. Instead, he selected seven countries – including Italy, Japan, and the United States – that fit his narrative that higher fat intake correlated with higher rates of heart disease.

This selective selection has been criticized as a classic example of cherry picking, where researchers pick out data that supports their hypothesis while ignoring conflicting evidence.

The consequences of his work

Ancel Keys' work led to a massive shift in how diet was understood and recommended. His research helped cement the idea that fat – and especially saturated fat – was dangerous and needed to be avoided.

This led to dietary advice that encouraged people to eat less fat and more carbohydrates, which eventually became the standard for many countries' nutritional policies.

Ironically, it was not just science, but politics and economics that played a role in this development. The food industry saw an opportunity to market “fat-free” products loaded with sugar and refined carbohydrates as “healthy alternatives,” and the government supported these changes.

Debunking Keys' hypothesis

In the decades since Keys' work, many researchers have challenged his conclusions. Large studies have shown that the relationship between saturated fat, cholesterol, and heart disease is far more complex than Keys claimed. Examples of this include:

1. Absence of clear evidence: Several extensive meta-analyses have shown that there is no clear association between saturated fat intake and an increased risk of cardiovascular disease.
   
2. Paradoxes that disprove the hypothesis: "The French Paradox" is a good example. The French eat a lot of saturated fat but have low levels of heart disease, which contradicts Keys' hypotheses.
   
3. New understandings of cholesterol: Modern research shows that LDL cholesterol (the type Keys believed was harmful) actually exists in several subgroups, some of which are harmless while others can be problematic, making total cholesterol a useless indicator of health risk.
   
4. The PURE Study: This large international study found that saturated fat intake was not associated with an increased risk of heart disease and could actually be beneficial in certain cases.

Ancel Keys: A controversial man

Keys was known as a confident and uncompromising person who was not afraid of conflict. He tended to dominate debates and marginalize scientists who disagreed with him.

A famous rival, John Yudkin, who argued that sugar, not fat, was the real culprit behind heart disease, was almost professionally destroyed by Keys' attacks on his research and reputation.

Keys lived a long life, reaching over 100 years, and many of his supporters used this as evidence of his health and dietary recommendations. Yet there is little doubt that his work has had negative consequences. His work laid the foundation for decades of nutritional dogma that is now being re-evaluated.

We have to see how the human animal has developed up to now, and there is a lot we can see with the naked eye that indicates that the advice we have been given has made us fatter and sicker.

Reflections

Ancel Keys' story is an example of how a dominant scientific voice can shape politics and societal perceptions for generations. It also shows how science can be influenced by personalities, politics, and financial interests, and why it is so important to ask questions and remain open to new data.

His contributions to nutritional science cannot be ignored, but they must be understood in light of his limitations and errors.

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Photos: Wikimedia Commons

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