Tokelau is a group of three atolls located in the South Pacific Ocean with approximately 1400 inhabitants. Administratively it belongs to New Zealand.
From a dietary point of view the case of Tokelau is very interesting: we can observe what happens when a population transitions from their traditional diet to a more westernized one, and back.
When Captain Wilkes visited Tokelau with his scientists, they reported that the people living there were very healthy, and to their surprise most of their diet was composed of coconut and fish, and some breadfruit (a starchy melon). There were no signs of plant cultivation.
In the 1920s, their diet was:
- 70% from coconut. So, more than 50% of this diet was fat.
- 90% of this fat, was saturated fat.
- skin diseases
- infectious diseases (chicken pox, measles, leprosy). No chronic diseases were recorded (trained physicians had been available since 1917).
In the 1960s, half of the population moved to New Zealand, and on the island, imported food became widely available.
The changes in their diet (saturated fat was replaced by carbohydrates):
- decrease in coconut consumption
- increase in sugar and flour consumption
- canned meat, frozen foods and biscuits were introduced
- they started to smoke, and alcohol consumption started as well
The new health implications:
- heart disease
In 1979, there was a cargo ship problem, so the delivery of processed foods stopped for 5 months. The inhabitants had no choice but to return to their original diet.
This is what the New Zealand Herald reported:
"There was no sugar, flour, tobacco and starch food 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 their pre-European diet of coconut and fish. Many people lost weight and felt very much better including some of the diabetics."After this period of isolation, processed foods were reintroduced. The results were:
- weight gain and high blood pressure, higher risk of heart disease
We could explain the increase in chronic diseases in different ways if we compare the 2 groups of people: those who remained on the island and those who migrated to New Zealand. For this, we should look at the TIMS (Tokelau Island Migration Study). In this study (overview), a lower incidence of chronic diseases was found among those who remained in Tokelau, than those who settled in New Zealand.
Could smoking explain the difference? As it turns out from the Tokelau Study, those left on the island smoked more on average than those settled in New Zealand. Smoking cannot explain the chronic disease pattern.
Age: actually those who settles in New Zealand were younger. So, age cannot explain either the higher prevalence of disease among the settlers.
Exercise: the settlers were engaged in heavy labor (factory works) compared to those remaining in Tokelau. So more exercise did not help to prevent the development of chronic diseases.
The only notable difference in their lifestyle was the amount of fat versus carbohydrate consumed. Those on Tokelau still consumed a diet higher in saturated fat compared to those in New Zealand. (Another study saturated fat intake.)
"[...] if diabetes, coronary heart disease, obesity, gout and hypertension appear simultaneously in populations, as they did in the Tokelauan experience, and are frequently found together in the same patients, then they are very likely to be manifestations of a single underlying pathology."
- Gary Taubes