In 1940, Arizona had the lowest rate of diabetes in the country, with only 755 cases total, 73 of them among Native Americans, such as the Pima, who lived on reservations. By the 1960s, 50% of Native American adults in Arizona were diabetic: the most shocking spike in diabetes in history. Isolated from the rest of the population for generations, the Pima began to integrate into mainstream American culture during World War II when some members of the tribe were drafted into the military and others began working in factories near Phoenix. Over the next few decades the diabetes rate skyrocketed along with obesity—in 1971 researchers noted that two-thirds of Pima men and over 90% of the women were considered overweight, if not obese.
Taubes argues that because the Pima changed their diet so suddenly from sustenance farming to a sugar-rich Western diet, the population had little time to adapt, quickly becoming insulin-resistant.