The remarkable health of the islanders of Crete and Corfu in Keys’s Seven Countries Study—and thus the supposedly salubrious effects of the Mediterranean diet itself—could also be explained by the lack of sugar and white flour. Despite the popularity of the Mediterranean diet today, our understanding of what exactly such a diet is—particularly in Crete and Corfu, where Keys’s study had documented such remarkably low mortality rates—is based on only two dietary surveys: Keys’s study itself, which analyzed the Cretan diet in 1960, and a Rockefeller Foundation study in 1947. According to the Seven Countries Study, the Cretan diet circa 1960 included a total of only sixteen pounds a year of sugar, honey, pastries, and ice cream. According to the Rockefeller study, the Cretan diet included only ten pounds a year of sugar and sweets, and the considerable bread consumed was all wholemeal. The reported benefits of the Mediterranean diet, therefore, could be attributed to the fish, olive oil, and vegetables consumed, as it is today, but they could also be due to the minimal quantities of sugar and the absence of white flour.

This lack of concern for any potential health-related difference between vegetables and starches, on the one hand, and refined starches and sugars, on the other, has haunted cancer research as well. Speculation that dietary fat caused breast, colon, and prostate cancer began in the 1970s, with the same international comparisons that led to the heart-disease hypothesis in the 1950s. Cancer epidemiologists simply compared carbohydrate, protein, and fat contents of diets in different countries with the mortality from various cancers. And these investigators, too, concluded that differences in cancer rates could be explained by differences in fat consumption and animal-fat consumption, particularly between Japan and the United States. They did not serve science well by ignoring sugar consumption and the difference between refined and unrefined carbohydrates.

These preliminary studies then prompted hundreds of millions of dollars of studies that failed to confirm the initial hypothesis that fat or animal fat led to cancer. (Even in the past few years, similar studies have attributed rising cancer rates in China to the increased consumption of fat, while again paying no attention to sugar or the refinement of the carbohydrates in the diets.) In 1975, Richard Doll and Bruce Armstrong published a seminal analysis of diet and cancer, in which they noted that, the higher the sugar intake in different nations, the higher both the incidence of and mortality from cancer of the colon, rectum, breast, ovary, uterus, prostate, kidney, nervous system, and testicles.*35 Still, epidemiologists fixated on the fat-cancer hypothesis and made no attempt to measure the refined carbohydrates in the populations they studied. As a result, a joint 1997 report of the World Cancer Research Fund and the American Institute for Cancer Research, entitled Food, Nutrition and the Prevention of Cancer, said this: