The epidemiologic truth is that virtually all poor, nonindustrial societies have very low rates of heart disease. Most of them also have very low rates of sugar consumption, very low rates of fat consumption, fairly low rates of urbanization, and many other differences from we modem people who live in Europe and North America. How do we tell what causes the heart disease?
A generation ago, the dean of British nutritionists, Dr. John Yudkin, and Dr. Ancel Keys, mentor for a large number of American nutritionists, conducted a running intellectual battle over epidemiology. Keys would study nations and cultures with varying degrees of heart disease and show how profoundly heart disease correlated with fat intake. Yudkin would look at the same statistics and find an almost identical correlation with sugar intake. The fact is that in over 90% of cultures there is a strong correlation between fat intake and sugar intake. Thus to choose between the two theories, we must look at the exceptions. Let’s do that.
The first thing we can notice is that in two primitive cultures, the Eskimos of North America and the Masai of East Africa, a high fat diet correlates not with heart disease but with virtually the complete absence of heart disease.
Let’s look at a couple of atypical Western countries. In Iceland, heart disease (and diabetes) was almost unheard of until the 1930s although the Icelanders ate a diet tremendously high in fat. In the early 1920s, however, refined carbohydrates and sugar arrived in the Icelandic diet and true to Cleave’s rule of 20 years, the modem degenerative diseases arrived on schedule. Finally in Yugoslavia and Poland, the development of high heart disease rates in the middle of this century was concomitant with a quadrupling of the sugar intake and occurred despite a fall in animal fat intake.
These studies prove nothing. In general, epidemiological studies never do, but they do cast serious doubt, just as an examination from history does, on the theory that high fat diets are the main cause of the epidemic of 20th century heart disease.