Good Calories, Bad Calories

Within two years, Burkitt had extended his hypothesis from appendicitis, diverticulitis, and colon cancer to all chronic diseases of civilization. In the process, Cleave’s refined-carbohydrate hypothesis of saccharine diseases was transformed into Burkitt’s fiber hypothesis of Western diseases. This transformation of the causal agent of disease from the presence of carbohydrates to the absence of fiber may have been influenced by factors other than science—Burkitt’s close association with Harold Himsworth in particular. Himsworth had been secretary of the Medical Research Council when Burkitt was hired, and he had been publicly effusive about Burkitt’s contributions to modern medicine. It was Himsworth’s research that had been responsible for convincing diabetologists that sugar and other carbohydrates were not the cause of diabetes. Indeed, Cleave and Campbell had presented their saccharine-disease theory in the context of diabetes as a refutation of Himsworth’s scholarship as much as Joslin’s. That Burkitt would find Cleave’s general thesis compelling but the details unacceptable in light of Himsworth’s own work and beliefs is quite possible. Burkitt would often tell the story of how Himsworth had convinced him of the importance of paying attention to those factors that were absent in searching for the causative agents of disease. “Denis,” Burkitt recalled Himsworth telling him, “do you remember the story in Sherlock Holmes when Holmes said to Watson: ‘The whole clue, as I see it, to this case lies in the behavior of the dog.’ And Watson said: ‘But, sir, the dog did nothing at all.’ ‘That,’ said Holmes, ‘is the whole point.’ And it often is in medicine…. The clue can lie in what is not there rather than what is there.” In this case, fiber was not there. Burkitt also seemed motivated by the simple expediency of emphasizing the positive benefits of fiber rather than the negative effects of sugar and flour, which seemed like a hopeless cause. “[Sugar] is simply an integral part of the daily diet and emphatically is here to stay,” Burkitt’s collaborator Alec Walker said. Better to say Don’t Forget Fibre in Your Diet, which was the title of Burkitt’s 1979 diet book, than to say, Don’t eat sugar, flour, and white rice, and drink less beer.

The final transformation of Cleave’s refined-carbohydrate hypothesis into Burkitt’s fiber hypothesis came primarily through the efforts of Burkitt’s colleague Hugh Trowell, who had spent thirty years as a missionary physician in Kenya and Uganda, beginning in 1929. This had been a time, as Trowell later explained, when scores of British doctors working for the colonial service and missionary hospitals in the Kenyan highlands had the unprecedented experience of watching the native population of “three million men, women and children…emerge from pre-industrial life and undergo rapid westernization.” After Trowell retired to England in 1959, he published Non-infective Disease in Africa, which was the first rigorous attempt to draw together the entire body of medical literature on the spectrum of diseases afflicting the native population of Africa.^*36 The Western diseases—a list almost identical to Cleave’s—were conspicuous by their absence.

Trowell’s experiences in East Africa had left him with the characteristic awareness of the diseases-of-civilization phenomenon. When he arrived in Kenya in 1929, he said, he had noticed that the Kenyans were all as thin as “ancient Egyptians,” yet when he dined with the native tribes, they always left food at the end of the meal and fed it to their domestic animals, which suggested that their relative emaciation was not caused by food shortages or insufficient calories. During World War II, according to Trowell, a team of British nutritionists was dispatched to East Africa to figure out how to induce the Africans in the British Army to put on weight, since they would not or could not do it. “Hundreds of x-rays,” Trowell recalled, “were taken of African intestines in an effort to solve the mystery that lay in the fact that everyone knew how to fatten a chicken for the pot, but no one knew how to make Africans…put on flesh and fat for battle. It remained a mystery.” Nonetheless, by the 1950s, fat Africans were a common sight, and in 1956 Trowell himself reported the first clinical diagnosis of coronary heart disease in a native East African—a Banting-esque high-court judge (five foot two and 208 pounds) who had lived in England and had been eating a Western diet for twenty years. In 1970, Trowell returned to East Africa and described what he saw as “an amazing spectacle: the towns were full of obese Africans and there was a large diabetic clinic in every city. The twin diseases had been born about the same time and are now growing together.”