The hidden truth behind Ancel Keys’ famous fat graph


For a while, in the middle of the last century, there was a scientific struggle. Was fat or sugar to blame for cardiovascular disease? Ancel Keys was the champion of the first theory; Professor John Yudkin of the other. Keys won, but not all of the data he used to make his arguments was a fair representation of reality.

The left graph above was famously used sixty years ago by Keys, to support his idea that fat intake was responsible for heart disease. But as the right graph shows, the same data could just as easily have implicated sugar. Countries eating higher amounts of fat were simultaneously eating more sugar. It was just a question of what you were looking for.

Since that time, we’ve spent half a century fearing natural fat, and instead eating more carbs. At the same time, an epidemic of obesity and diabetes has occurred. Even though the association in the graph on the right can’t show cause-and-effect anymore than the graph on the left, it may be time to reconsider: maybe Yudkin was right.


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  1. Brett Graham
    Ancel Keyes did not cherry pick his data. If he did he could have cherry picked 6 different countries to better support his hypothesis. He even explained the reason for his choices; he chose the countries with the most reliable data.
    As to the graph on the right, it's data from 1969, not from 1953. And by the way, why are we waving this graph around like its some kind of victory for fat? Look at the data points; fat correlates better than sugar for CVD. So correlation doesn't equal causation except when it satisfies your biases?
    Replies: #12, #16
  2. Richard Nikoley
    Wow. So cherry picked bias is bad if it's fat, but good if it's carbohydrate?
    Replies: #3, #5
  3. Dr. Andreas Eenfeldt, MD Team Diet Doctor
    No. Cherry picking is always risky. Furthermore, I don't recommend basing diet advice on ecological studies of country data at all. :)

    Fortunately we have dozens of high-quality RCT studies these days:

  4. Paul Meyer
    Exactly my thought on ecological (observational studies).
  5. Apicius
    Seriously, Nikoley? There's a reason your blog is no longer on this site.
  6. Brian Throop
    The sad fact is Keys is responsible for countless deaths and misery for pushing invalid data.
    Reply: #8
  7. Charlotte Braun
    Another sad fact is that doctors believe whatever the pharmaceutical companies say😤And a lot of cancers come from spraying our crops and allowing hormones and antibiotics in animals!💀
  8. Marisa
    Yes he did, the monster. I have done the math actually; at least with the statistics on diabetic and heart disease murders since the 1960's. In those 2 co-morbidities alone, nearly 35,000,000 murders over these last 5+ decades. Hitler killed 6,000,000. Then there's all the other diseases, like lung diseases, exacerbated by inflammation in the body from grains, bad oils and sugars, sleep apnea, and more.
    Reply: #13
  9. Andres Fernandes
    What is the evidence of this great "scientific struggle" over whether fat or sugar was to blame for cardiovascular disease. The scholarship and the media coverage from the period show that diverse experts argued that it had to do with stress, lack of exercise, dietary cholesterol, obesity, hypertension, "soft" water, etc., etc. Many doubted that it had anything to do with diet. Gary Taubes has everyone thinking that there was one issue of contention--fat or sugar--because if you don't believe it was fat then you must accept that it was sugar, his pet peeve. It was far more complex than that, and when death rates from heart disease unexpectedly began to decline, there was intense debate over what caused that too.
    Also, how come the death rates continued to decline even as intakes of sugar, high fructose corn syrup, etc. skyrocketed in the 70s, 80s, 90s? Obesity rates also increased at this time of falling heart disease mortality. Far more complex than anyone wants to admit, because there are just no easy answers.
    Reply: #22
  10. Dennise F
    Andres, thanks for reminding us. People did look into multiple reasons for heart disease and obesity. "Stress" became a popular term to explain the cause of certain illnesses. And remember the rise of exercise gurus like Jane Fonda and Richard Simmonds, so many people believed exercise was key. In perhaps a lesser way, some people believed that we needed fresh air and back to nature movements arose. I remember even tv shows showed the benefits of living in the mountains, because I grew up wanting to escape to Grizzly Adams country.
    People knew the issues were complex.
  11. Ann
    He died at the age of 100 and followed a Mediterranean diet I hear but does anyone know what he died from?
  12. Paolo Igotuam
    Of course both sugar and fats has showed correlation. That's the hypothesis... but then you have to prove that before making it a fact. Sugar has showed to be extremely harmful, but saturated fats didn't. They've jumped from the hypothesis to the fact and suddenly the entire world was on a low fat diet...
  13. Say May
    People might have took him wrong, which may be the cause for all the deaths. Im not sure what exactly he stated in his hypothesis, however upon searching his name, multiple sources say that he was a proponent of The Mediterranean Diet, which upon researching is great comprised of Extra Virgin Olive Oil as the most ubiquitous fat in that diet. Extra Virgin Olive Oil is actually very healthy and happens to be a mostly unsaturated fat, and since it is low in saturated fat, many people probably began to believe EVERY Fat that is unsaturated is good for you, which made people go to the highly processed unsaturated fats such as Canola Oil, Soybean Oil, Palm Oil, etc... That happen to be cheap and easier to access which are also the most harmful. Also, according to, The Mediterranean diet follows this: Eat: Vegetables, fruits, nuts, seeds, legumes, potatoes, whole grains, breads, herbs, spices, fish, seafood and extra virgin olive oil. Eat in moderation: Poultry, eggs, cheese and yogurt. Eat only rarely: Red meat. Don’t eat: Sugar-sweetened beverages, added sugars, processed meat, refined grains, refined oils and other highly processed foods. Which seems to be a healthy diet. This overall seems like a very healthy diet. And it does say not to eat refined oils or grains which removes anything that could cause the deaths. And he did live to 100, but I don’t know im in a bind.
  14. Brendan Murray
    Lies, damn lies and statistics, as Mark Twain once said. "The number of deaths" -- what does that prove. Perhaps people live longer but sicker because pharmaceutical companies have developed drugs to keep them alive for longer. I have a simple philosophy, Stay healthy and your body will maintain its own weight and fat balance. Not an easy thing to do by any means when the food we have to choose from, is dictated by the large food? (over-priced and undernourished) multinationals -- motivated by greed and profit, not to further mankind in any way. -- And by the way, inherit good genes. So choose your parents wisely.
  15. 1 comment removed
  16. Stephen
    Actually the data found in Key's research partner's house after his death confirms, amongst other things - cherry picking.
  17. Miko
    Well, I have to say that graph on the right shows nicely that both sugar and saturated fat are leading to heart disease. I cannot see how that denies what Keys's said. It actually enriches it further :)
    Reply: #19
  18. 1 comment removed
  19. Polarbear
    Maybe you should read again what Paolo Igotuam said above.
  20. BB Rider
    France does not fit the graph very well. Why did he remove France from the published graph?
  21. Jeffrey schwartz
    Ansl keys was wrong. Type 2 and tyoe 3 diabetes directly corolates with the removal of fat replaced with sugar.. the food manufacturers. Figured out how to keep flour from rotting by removing the husk thus increasing the glycemic load in most breads and wheat products. Fat free became high sugar and high glycemic.. we eat proceesed wheat products for 30 yrs. Insulin runs through the body sanding down cell receptors that are locked to prevent further glucose uptake..once they are sanded down they can open when they need fuel.. same thing happends in brain cells. Brain dies.. muscle and organ cells die..remove processed wheat flour. Whole foods. Animal fat increase.. processed flour decrease..
  22. Neil
    You can't ignore smoking. We stopped being a smoking public over the last 50 years and that is the most likely explanation for the heart disease reduction. It should have been more, but the change in diet at the same time was so bad it held back the reduction.

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