Three-Way Street

Abstract

I N T H E E A R L Y 1 9 6 0 S , researchers from the National Institutes of Health (NIH) journeyed to the parched desert lands of the Gila River Indian Community in central Arizona to study the health of the Pima Indians. In the course of routine medical exams, they made a startling discovery: the Pima people proved to be fatter than any other group of people on Earth except for the Pacifi c Nauru islanders. Nearly half of those over the age of 35 had type 2, or adult-onset diabetes, eight times the national average. In order to survive in the desert, it seems that their thrifty genes may have evolved to carefully conserve fat through times of drought and famine. After World War II, when the tribe changed their traditional diet to an American one, their fat intake rose from about 15 percent to a whopping 40 percent of calories—and their genetic evolution backfi red.