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Welcome to this site, all interested in resilient farming!

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Friday, May 15, 2015

Ancel Benjamin Keys and the lipid hypothesis

The idea of cherry picking data in food science and studies is often associated with Ancel Keys, who died in 2004 at the age of 100. Keys completed studies at UC Berkeley, originally studying chemistry, but then receiving a BA in economics and political science, and a MS in zoology. He was a management trainee at Woolworth’s, but eventually received his PhD from Scripps Institution of Oceanography at the age of 26 in oceanography and biology. He also had a NRC fellowship studying fish physiology in Copenhagen  and contributed numerous papers on the subject. His second PhD, was in physiology, from Harvard.

Keys was probably best known for developing K-rations and popularizing the Mediterranean diet (lean meats, fruits and vegetables, olive oil).  A fish biologist and physiology expert from Cambridge, he was handpicked to conduct a meta analysis of a number of countries around the world, correlating saturated fat intake with the incidence of CV disease. He used one of his skills – multivariate analysis as represented in regression and limited the number of countries to a handful – what would become his famous “Seven Countries’ Study.” His work produced a (anti)lipid hypothesis, and a food industry that reifies all.

In the Seven Countries’ Study, the graphs he produced were clear, stark, and disturbing – showing a rapid increase in the incidence of heart disease with saturated fat intake. On the chopping block (so to speak) were everything from Big macs to pork chops to bacon.  Saturated fats and dietary cholesterol were under attack (cholesterol had been implicated, too). Results were widely accepted (including by me) and eventually formulated into “the lipid hypothesis,” which I referred to in both versions of Finding Balance.  The data seemed compelling  – and the conclusion – eat less fat, eat more plants -- an obvious path to weight management and health. The American Heart Association formed soon after that, heavily promoting low-fat messages via recipes representing “heart-friendly foods.”

Many have argued that Keys had been highly selective with his data – ignoring countries that did not fit the pattern. This misrepresentation of science is presented with much fanfare in Robert Lustig’s The Bitter Truth, as well as in many scholarly critiques, not to mention popular ones.[1] The consequences of this “mis-exercise,” especially in light of the results of the multi-year Framingham study, are astounding.[2]

[1] For example, see Gary Taubes, one of Keys’ most ardent critics. Taubes introduces the idea that #B10 a calorie is not a calorie, even eating the same amount. There is a difference between what you eat and how much weight you gain, Taubes says (refs). For example, he refutes the bathtub model, of weight gain, merely calories in-calories out. Carbs as calories-in is the problem. Frankly, most of the critiques are in popular media, and not in refereed journals, save the Framingham study results. It’s, however, worth looking at the anger of internet responses leveled at critiques -- for example at Denise Minger’s critique of The China Study.
[2] Since then, The Framingham Heart Study, begun in 1948 with 6,000 people from Framingham, Massachusetts, has refuted Keys’ research. "In Framingham, Mass, the more saturated fat one ate, the more cholesterol one ate, the more calories one ate, the lower the person's serum cholesterol. . .We found that the people who ate the most cholesterol, ate the most saturated fat, ate the most calories, weighed the least and were the most physically active." The study did show that those who weighed more and had abnormally high blood cholesterol levels were slightly more at risk for future heart disease; but weight gain and cholesterol levels had an inverse correlation with fat and cholesterol intake in the diet. (refs)

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