Good Calories, Bad Calories

By the mid-1960s, the population of Tokelau had grown to almost two thousand and the New Zealand government, concerned about the threat of overpopulation, initiated a voluntary migration program during which more than half the Tokelauans moved to the mainland. From 1968 to 1982, a team of New Zealand anthropologists, physicians, and epidemiologists led by Ian Prior took the opportunity to study the health and diet of the emigrants as they resettled, as well as those who remained behind on the islands as their diets were progressively Westernized. This Tokelau Island Migration Study (TIMS) was a remarkably complete survey of the health and diet of all men, women, and children of Tokelauan ancestry. It was also quite likely the most comprehensive migration study ever carried out in the history of nutrition-and-chronic-disease research.

On Tokelau, the primary changes during the course of the study came in the mid-1970s, with the establishment of a cash economy and trading posts on the atolls. The year-round availability of imported foods led to a decrease in coconut consumption to roughly half of all calories. This was offset by a sevenfold increase in sugar consumption^*38 and a nearly sixfold increase in flour consumed—from twelve pounds per person annually to seventy pounds. The islanders also began eating canned meats and frozen foods, which they stored in freezers donated by the United Nations; by 1980, six pounds of mutton per capita, three pounds of chicken backs, and five pounds of tinned corned beef had been consumed. (In comparison, 270 pounds of fish were caught per islander in 1981.) By then, the trading ships were also delivering annually some eighteen pounds per person of crackers, biscuits, and Twisties, a cheese-flavored corn snack. Smoking increased dramatically, as did alcohol consumption.

Through the 1960s, the only noteworthy health problems on the islands had been skin diseases, asthma, and infectious diseases such as chicken pox, measles, and leprosy. (Modern medical services and a trained physician had been available in Tokelau since 1917.) In the decades that followed, diabetes, hypertension, heart disease, gout, and cancer appeared. This coincided with a decrease in cholesterol levels, consistent with the decrease in saturated-fat consumption. Average weights increased by twenty to thirty pounds in men and women. A similar, albeit smaller, trend was seen in Tokelauan children. The only conspicuous departure from these trends was in 1979, when the chartered passenger-and-cargo ship Cenpac Rounder ran aground and the islanders went five months without a food or fuel delivery. “There was no sugar, flour, tobacco and starch foods,” reported the New Zealand Herald, “and the atoll hospitals reported a shortage of business during the enforced isolation. It was reported that the Tokelauans had been very healthy during that time and had returned to the pre-European diet of coconut and fish. Many people lost weight and felt very much better including some of the diabetics.”

As for the migrants to New Zealand, the move brought “immediate and extensive changes” in diet: bread and potatoes replaced breadfruit, meat replaced fish, and coconuts virtually vanished from the diet. Fat and saturated-fat consumption dropped, to be replaced once again by carbohydrates, “the difference being due to the big increase in sucrose consumption.” This coincided with an almost immediate increase in weight and blood pressure, and a decrease in cholesterol levels—all more pronounced than the increases witnessed on Tokelau. Hypertension was twice as common among the migrants as among the Tokelauans who remained on the islands. The migrants also had an “exceptionally high incidence” of “diabetes, gout, and osteoarthritis, as well as hypertension.” Electrocardio-graphic evidence suggested that the “migrants were at higher risk for coronary heart disease than were non-migrants.”