Good Calories, Bad Calories

These sugarcane cutters, in whom, as Campbell noted, “diabetes is virtually absent,” turned out to be pivotal, in that later generations of diabetologists would cite them as compelling evidence that diabetes was not caused by eating sugar. Campbell, however, believed it was the refining of the sugar, which allowed for its quick consumption and metabolism, that did the damage; chewing sugarcane resulted in a slow intake of sugar that he believed would be relatively benign. Moreover, cane cutters would cut and move by hand as much as seven tons of sugarcane each day, which required an extraordinary effort that suggested to Campbell—as it had to Frederick Allen a half-century before—that a physically active lifestyle might ward off the danger of excessive sugar consumption, perhaps by burning the sugar as fuel to maintain the necessary “huge output of energy” before it could do its damage. “There are few occupations in the world,” Campbell wrote, “which entail such hard physical exertion as that involved in the cutting, moving, and stacking of sugar cane.”

Campbell also believed that diabetes required time to manifest itself. The cane cutters had been receiving their refined-sugar ration for only a decade at most. From his medical histories of the diabetic Zulus at his clinic, Campbell found what he called a “remarkably constant period in years of exposure to town life” before rural Zulus who had moved permanently into Durban developed diabetes. “The peak ‘incubation period’ in 80 such diabetics,” he wrote, “lay between 18 and 22 years.” Thus, Campbell suggested that diabetes would appear in a population to any extent only after roughly two decades of excessive sugar consumption, just as lung cancer from cigarettes appears on average after two decades of smoking. He also suggested that, if international statistics were any indication, the kind of diabetes epidemic they were experiencing among Natal Indians—or, for that matter, most Westernized nations—required a consumption of sugar greater than seventy pounds per person each year.

Campbell appears to be the first diabetologist to propose seriously an incubation period for diabetes. Joslin’s textbooks suggest he believed that if sugar consumption caused diabetes the damage could be done quickly—in a single night of “acute excess.” In arguing against the sugar theory of diabetes, Joslin said that no one to his knowledge had ever developed the disease after drinking the sugar solution used in a type of diabetes test known as a glucose-tolerance test.^*32 By the same logic, you could imagine that smoking a pack of cigarettes in an evening might cause lung cancer within the next few weeks in the rare unfortunate first-time smoker. That it has not been known to happen does not imply that tobacco is not a potent carcinogen.

In the early 1960s, Campbell began corresponding with a retired physician of the British Royal Navy, Surgeon Captain Thomas Latimore “Peter” Cleave. In 1966, they published Diabetes, Coronary Thrombosis and the Saccharine Disease, a book in which they argued that all the common chronic diseases of Western societies—including heart disease, obesity, diabetes, peptic ulcers, and appendicitis—constituted the manifestations of a single, primary disorder that could be called “refined-carbohydrate disease.” Because sugar was the primary carbohydrate involved, and the starch in white flour and rice is converted into blood sugar in the body, they opted for the name saccharine disease (“saccharine,” in this instance, meant “related to sugar” and rhymes with “wine,” in their usage, not “win,” as the artificial sweetener does).

After the book was published, Campbell returned to working exclusively on diabetes. Cleave tried to convince the medical establishment of the strength of evidence linking chronic diseases to the refining of carbohydrates, with little success. One biostatistician who insisted the idea should be taken seriously was Sir Richard Doll, director of the Statistical Research Unit of Britain’s Medical Research Council, who wrote the introduction to Diabetes, Coronary Thrombosis and the Saccharine Disease. In the early 1950s, Doll had published the seminal studies linking cigarettes to lung cancer. Doll later said of Cleave’s research, “His ideas deserved a lot more attention than they got.”

The primary obstacle to the acceptance of Cleave’s work was that he was an outsider, with no recognizable pedigree. He had spent his entire career with the British Royal Navy, retiring in 1962, after spending the last decade directing medical research at the Institute of Naval Medicine. Much of Cleave’s early career was spent in British naval hospitals in Singapore, Malta, and elsewhere, which gave him firsthand experience of how chronic-disease incidence could differ between nations.