Good Calories, Bad Calories (44 page)

There is a tendency among public-health authorities, obesity researchers, and health writers to discuss obesity as though the problem on a societal scale were only twenty or thirty years old, but this confuses the problem of obesity with the current obesity epidemic. Because these last few decades also coincide with the spread of McDonald’s and other global purveyors of high-fat fast foods, obesity can conveniently be blamed on fast food by virtue of this association. (It has also, by this same logic, been popularly blamed on high-fructose corn syrup.) But the research literature of obesity dates back further than the epidemic, and by including all of the relevant observations over the years, we can begin to rule out competing hypotheses. Any hypothesis that purports to explain how obesity is caused, after al , should explain the emergence of obesity in any population and at any time, not just the increasing obesity in the past few decades.

The Pima Indians of southwestern Arizona are now infamous for having the highest rates of obesity and diabetes in the United States. Today the standard explanation for obesity among the Pima is that they have succumbed, as we al have, to prosperity and the toxic environment of American life.

Over the last century, the Pima supposedly experienced a nutrition transition—an exaggerated version of the changing-American-diet story. Farmers and hunters became relatively sedentary wage-earners, while their diet changed from one very low in fat and high in fiber-rich carbohydrates and vegetables to a modern high-fat, high-sugar American diet. “As the typical American diet became more available on the reservation after the [Second World] war,”

according to an NIH report entitled The Pima Indians: Pathfinders for Health, “people became more overweight.” “If the Pima Indians could return to some of their traditions,” explained one NIH authority, “including a high degree of physical activity and a diet with less fat and more starch, we might be able to reduce the rate, and surely the severity, of unhealthy weight in most of the population.”

The problem with this version of the Pima history is that obesity and overweight had been evident a century ago, when the relevant nutrition transition was from relative abundance to extreme poverty. From November 1901 to June 1902, the Harvard anthropologist Frank Russel lived on the Pima reservation south of Phoenix studying the tribe and its culture. Many of the older Pima, Russel noted in a report of the Bureau of American Ethnology,

“exhibit a degree of obesity that is in striking contrast with the ‘tal and sinewy’ Indian conventionalized in popular thought.”

Obesity among the Pima is not a new phenomenon, as demonstrated by this photo of “Fat Louisa” taken in 1901 or 1902 by the Harvard anthropologist Frank Russell.

Russel ’s assessment of the Pima’s relative corpulence was then confirmed by the anthropologist and physician Aleš Hrdli ka, who visited the Pima reservation in 1902 and 1905. “Especial y wel -nourished individuals, females and also males, occur in every tribe and at al ages,” Hrdli ka reported, “but real obesity is found almost exclusively among the Indians on reservations.”

For perhaps two mil ennia, the Pima had lived as both hunter-gatherers and agriculturalists. Game was abundant in the region, as were fish and clams in the Gila River. When the Jesuit missionary Eusebio Kino arrived among the Pima in 1787, the tribe was already raising corn and beans on fields irrigated with Gila River water. In the decades that fol owed, they took to raising cattle, poultry, wheat, melons, and figs. They also ate mesquite beans, the fruit of the saguaro cactus, and a mush of what Russel later cal ed “unidentified worms.” In 1846, when a U.S. Army battalion passed through Pima lands, the battalion’s surgeon John Griffin described the Pima as “sprightly” and in “fine health.” He also noted that the Pima had “the greatest abundance of food, and take care of it wel , as we saw many of their storehouses ful of pumpkins, melons, corn &c.”

Life began to change dramatical y the fol owing year, when a wagon route was opened to California “by way of Tucson and the Pima vil ages.” This became the southernmost overland route for the California gold rush that began in 1849; tens of thousands of travelers passed through the Pima vil ages on the way west over the next decade. They relied on the Pima for food and supplies.

With the arrival of Anglo-American and Mexican settlers in the late 1860s, the prosperity of the Pima came to an end, replaced by what the tribe referred to as “the years of famine.” Over the next quarter-century, these newcomers hunted the local game almost to extinction, and the Gila River water, on which the Pima depended for fishing and irrigating their own fields, was “entirely absorbed by the Anglo settlements upstream.” By the mid-1890s, the Pima were relying on government rations to avoid starvation, and this was stil the situation when Hrdli ka and Russel arrived in the early 1900s.

Both Hrdli ka and Russel struggled with the dilemma of poverty coincident with obesity. Russel knew that the life of these Indians was arduous;

sedentary behavior could not be a cause of obesity in the Pima. Instead, he proposed that a dietary factor was responsible. “Certain articles of their diet appear to be markedly flesh producing,” Russel wrote. Hrdli ka suggested that “the role played by food in the production of obesity among the Indians is apparently indirect.” He suggested that life on the reservation might be relatively sedentary and this could play a role—“the change from their past active life to the present state of not a little indolence”—but he did not appear particularly confident about it. After al , he wrote, obesity was quite rare among the Pueblo, “who have been of sedentary habits since ancient times.” And obesity among the Pima was found “largely but not exclusively” in the women, and the women of the tribe worked considerably harder than the men, spending their days harvesting the crops, grinding corn, wheat, and mesquite beans and carrying whatever burdens were not carried by pack animals.

Hrdli ka also noted that by 1905 the Pima diet already included “everything obtainable that enters into the dietary of the white man,” which raises the possibility that this might have been responsible for the obesity. At the half-dozen trading posts that opened on the Pima reservation after 1850, the Indians took to buying “sugar, coffee and canned goods to replace traditional foodstuffs lost ever since whites had settled in their territories.”

Neither Hrdli ka nor Russel suggested that the U.S. government rations might be the cause of obesity. But if the Pima diet on government rations was anything like that of tribes reduced to similar situations at the time on which data exist—including the Sioux on the Standing Rock Reservation in the Dakotas—then almost 50 percent of their calories came from sugar and flour.

Obesity in association with “widespread poverty” was documented again on the Pima reservation in the early 1950s by Bertram Kraus, a University of Arizona anthropologist working with the Bureau of Indian Affairs. According to Kraus, more than 50 percent of the children on the Pima reservation could legitimately be described as obese by their eleventh birthday. The local Anglos, Kraus wrote, got leaner as they got older (at the time, at least); this was not the case with the Pima. Kraus lamented the absence of dietary data to assess the nutritional state of the tribe, but this situation was remedied a few years later by Frank Hesse, a physician at the Public Health Service Indian Hospital on the Gila River Reservation. Hesse noted that the Pima diet of the mid-1950s was remarkably consistent from family to family and consisted of “mainly beans, tortil as, chili peppers and coffee, while oatmeal and eggs are occasional y eaten for breakfast. Meat and vegetables are eaten only once or twice a week.” Hesse neglected to assess sugar consumption, but he did note that “a large amount of soft drinks of al types is consumed between meals.” Hesse then concluded that 24 percent of the calories consumed by the Pima (the soft drinks not included) were from fat, which is certainly low by modern standards.*69

Over the next twenty years, the prevalence of obesity and diabetes among the Pima continued to rise, now coincident with a change in the foods distributed by government agencies and sold in the reservation trading posts. By the late 1950s, according to the Indian Health Service in Tucson, “large quantities of refined flour, sugar, and canned fruits high in sugar” were being distributed widely on the reservations, courtesy of a surplus commodity food program run by the U.S. Department of Agriculture. When mechanization of the local agriculture industry brought a cash economy to the Pima, the local stores and trading posts “started to carry high caloric pre-packed sweets, such as carbonated beverages (i.e., ‘soda pop’), candy, potato chips, and cakes.” “Soda pop is used in immense amounts,” as one 1962 study described it.