People might disagree on many things about Dr. Ancel Keys, but they’ll all agree on one thing: Ancel Keys was an influential character, and he most certainly influenced diet and fat consumption.
Who is Ancel Keys?
Dr. Ancel Keys was a public health scientist most famous for establishing a link between heart disease and cholesterol. He was born in 1904 in Colorado, United States, and lived a long life, passing in Minnesota in 2004.
Growing up, when Keys was bored at a birthday party or family event, he was known for taking out his chemistry set and experimenting. As a young man, Keys had quite a few jobs, including working on an oil ship headed to China.
Ancel Keys attended the University of California, Berkeley, earning a Ph.D. in oceanography and biology in 1930. He earned a second Ph.D. in physiology at Cambridge in 1938. By 1936, Keys had become the professor at the University of Minnesota, where he founded the Laboratory of Physiological Hygiene. He directed this laboratory from 1939 until his retirement in 1975.
In World War II, Dr. Ancel Keys created the K-ration, which the U.S. military used to feed thousands of soldiers. His interest in chemistry, nutrition, and human health only heightened, and in the 1930s, Keys took part in various studies of energy, nutrition, and more. Most of his studies were observational, and some were clinical.
Keys performed various experiments in calorie deprivation. In 1961, he graced the cover of TIME magazine. Keys and his wife popularized and advocated for the Mediterranean diet with best-selling books, lectures, and more [1,2].
Research shows the Mediterranean diet has been associated with a plethora of health benefits, including a reduced risk of developing certain chronic diseases [3,4]. Keys was one of the first to promote the Mediterranean diet that emphasized unsaturated fats over saturated, and fish and seafood over animal foods from the land. The Mediterranean diet focuses on fruit, vegetables, pasta, bread, and olive oil. Key’s message wasn’t so much about ditching all fats, rather, replacing saturated fat with unsaturated fats.
How Did Ancel Keys Influence Diet and Fat Consumption?
One key point stuck in Dr. Keys’ mind: American business executives who were presumably the best-fed had higher rates of heart disease than post-war Europe, where rates of cardiovascular disease had decreased significantly in the wake of reduced food supplies.
Dr. Keys believed there could be a correlation between cholesterol levels and cardiovascular disease, so he initiated a study of Minnesota businessmen. According to Keys, the studies revealed associations between the cardiovascular rate of a population and the average serum cholesterol and per capita intake of saturated fatty acids.
Dr. Keys was reportedly the first to study a potential correlation between heart disease and diet in large ethnic populations. In 1958, along with colleagues from other countries, Keys started the well-known Seven Countries Study designed to refute early skepticism about the links between cholesterol, diet, and heart disease. Keys traveled to countries around the world to investigate claims of heart disease and was surprised when there was no mention of coronary disease in medical charts of countries like Italy.
Dr. Keys noticed that heart disease rates varied significantly throughout the world, with places like Japan having far lower rates than Finland and some other countries. He realized that the Japanese diet was generally lower in fat and particularly saturated fat. He also observed that in Finland, hard-working farmers buttered their cheese, and many had heart disease.
Keys actively promoted his study findings and played a pivotal role in the cholesterol controversy that arose. He recommended a diet with around 30% of the calories from fat, a far cry from the ketogenic diet with 70% or more. Ancel Keys was certainly passionate and vocal on his stance that cholesterol was a major cause of heart disease and that dietary saturated fat was also a major player.
Many scientists were concerned that these associations didn’t provide scientific certainty and that more research, particularly clinical and laboratory research, was needed before a conclusion could be safely reached.
Initially, the food industry and medical associations criticized Dr. Keys’ views, but later, many of these views were accepted. Many competing food industry groups, food faddists, physicians, insurance companies, and health promotion associations took these somewhat ambiguous studies and used them to pursue their agendas.
Unfortunately, by the 1980s, all fats were subject to the ‘fat-is-bad’ mantra that began to dominate the food industry. So, does saturated fat deserve this notorious, harsh reputation and demonization? Is saturated fat really that bad for your health, and does it really play a role in heart disease? How does saturated fat impact serum cholesterol?
The Controversy Around Cholesterol and Dietary Saturated Fat
Undoubtedly, Dr. Keys’ research had a big impact on countless individuals following dietary guidance issued to promote health and manage disease. He introduced the diet-lipid-heart disease hypothesis and spent much of his career investigating this hypothesis.
Health and nutrition experts and researchers are still divided when it comes to cholesterol and heart disease, and several factors might influence cholesterol, such as infection and inflammation .
Many health professionals still view saturated fat as the artery-clogging fat associated with heart disease. Still, mounting research reveals this isn’t the case, and heart disease is much more complex and multifaceted than ‘bad’ cholesterol in a clogged drainpipe. Saturated fat has been exonerated in much of the literature of recent decades, with research showing that dietary saturated fat has little to no influence on serum cholesterol levels.
Extensively researched books like Good Calories Bad Calories by Gary Taubes and documentary films like Fat Fiction featuring leading health experts continue to exonerate these natural, delicious fats. This wealth of information, science, and clinical and anecdotal evidence strongly questions and disputes the low-fat heart-healthy diet recommendations and the demonization of saturated fat.
Take coconut oil as one example. Coconut oil is especially high in saturated fat with a whopping 87%!  Unlike the polyunsaturated fatty acids found in vegetable oil, saturated fats like those in coconut oil retain their structure and remain completely safe for consumption when heated to higher temperatures. A 1981 study on the Tokelau island chain in the South Pacific revealed that they consume over 60% of their calories from coconuts. Still, they have excellent overall health and exceptionally low heart disease rates in the population .
Other studies show the fatty acids in coconut oil can raise HDL cholesterol in the blood – the good type of cholesterol that might help reduce the risk of heart disease and improve metabolic and heart health [8,9,10,11].
Eggs are another example, and despite the misinformation and vilification of eggs, over half a century of research has now clearly demonstrated that egg intake isn’t associated with increased health risk. Consuming eggs doesn’t significantly impact the concentration of blood cholesterol [12,13,14].
It’s also interesting to note that 1 cup of cooked mackerel, a fish, has almost 10 grams of saturated fat, which is more than some steaks!  Research repeatedly shows that lowering saturated fat consumption doesn’t reduce the risk of developing cardiovascular disease .
Some studies, such as the resurrected randomized 1960’s Sydney Diet Heart Study, found that volunteers who replaced most of the saturated fat in their diet with polyunsaturated fats high in linoleic acid actually had a higher risk of fatality from coronary heart disease .
The dietary habits of the United States shifted to fearing natural fat and consuming more sugar and carbohydrates. Other countries soon followed suit. An interesting twist is that the sugar industry allegedly paid scientists to downplay the link between sugar and heart disease, further shifting the blame to the devilish saturated fat. Many mainstream magazines, medical and science journals, and others wrote about the questionable science funded by the sugar industry.
It’s unclear why some studies and projects involving Ancel Keys that were supposed to be published were purposefully hidden in dusty basements for decades .
The Seven Countries Study
Ancel Keys’ Seven Countries Study involved Greece, Italy, South Africa, Spain, Finland, and Japan, but originally, it also included more nations, prompting accusations of cherry-picking data. Some experts believe Ancel Keys chose the countries that he knew would better represent his hypothesis, and that a viable link between sugar and heart disease could also be implicated in the graph that Keys used to implicate saturated fat.
Countries eating high amounts of fat were also eating more sugar. Nonetheless, these studies and graphs shouldn’t be used to determine cause and effect. Despite Dr. Keys and his studies, experts like Professor John Yudkin maintained that sugar was to blame [19,20,21,22].
It stands to reason that the true nature of science is never settled. Science should be ever-evolving with ongoing studies that continue to prove or disprove the original hypothesis.
3. Tosti, V., Bertozzi, B., & Fontana, L. (2018). Health benefits of the Mediterranean diet: Metabolic and molecular mechanisms. Journal of Gerontology, 73(3), 318-326. https://doi.org/10.1093/gerona/glx227
7. Prior, I. A., Davidson, F., Salmond, C. E., & Czochanska, Z. (1981). Cholersterol, coconuts, and diet on Polynesian atolls: A natural experiment: The Pukapuka and Tokelau Island Studies. American Journal of Clinical Nutrition, 34(8), 1552-1561. DOI: 10.1093/ajcn/34.8.1552
8. Famurewa, A. C., Ekeleme-Egedigwe, C. A., Nwali, S. C., Agbo, N. N., Obi, J. N., & Ezechukwu, G. C. (2018). Dietary supplementation with virgin coconut oil improves lipid profile and hepatic antioxidant status and has potential benefits on cardiovascular risk indices in normal rats. Journal of Dietary Supplements, 15(3), 330-342. DOI: 10.1080/19390211.2017.1346031
9. Gerhsuni, V. M. (2018). Saturated fat: Part of a healthy diet. Current Nutrition Reports, 7(3), 85-96. DOI: 10.1007/s13668-018-0238-x
10. Assuncao, M. L., Ferreira, H. S., Dos Santos, A. F., Cabral Jr, C. R., & Florencio, T. M. M. T. (2009). Effects of dietary coconut oil on the biochemical and anthropometric profiles of women presenting abdominal obesity. Lipids, 44(7), 593-601. DOI: 10.1007/s11745-009-3306-6
11. Cardoso, D. A., Moreira, A. S. B., De Oliveira, G. M. M., Luiz, R. R., & Rosa, G. (2015). A coconut extra virgin oil-rich diet increases HDL cholesterol and decreases waist circumference and body mass in coronary artery disease patients. Nutritcion Hospitalaria, 32(5), 2144-2152.
12. Réhault-Godbert, S., Guyot, N., & Nys, Y. (2019). The golden egg: nutritional value, bioactivities, and emerging benefits for human health. Nutrients, 11(3), 684. DOI: 10.3390/nu11030684
16. Chowdhury, R., Warnakula, S., & Kunutsor, S. (2014). Association of dietary, circulating, and supplement fatty acids with coronary risk. Annals of Internal Medicine, https://doi.org/10.7326/M13-1788
17. Ramsden, C. E., Zamora, D., Leelarthaepin, B., Majchrzak-Hong, S. F., Faurot, K. R., Suchindran, C. M., Ringel, A., Davis, J. M., & Hibbeln, J. R. (2013). Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: Evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis. British Medical Journal, DOI: https://doi.org/10.1136/bmj.e8707
18. Kearns, C. E., Schmidt, L. A., & Glantz, S. A. (2016). Sugar industry and coronary heart disease research: A historical analysis of internal industry documents. JAMA, 176(11), 1680-1685. DOI:10.1001/jamainternmed.2016.5394
21. Keys, A., Taylor, H. L., Blackburn, H., Brozek, J., Anderson, J. T., & Simonson, E. (1963). Coronary heart disease among Minnesota business and professional men followed fifteen years. Circulation, 28, 381-395. https://doi.org/10.1161/01.CIR.28.3.381
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