Good Calories, Bad Calories

The changing-American-diet story envisions the turn of the century as an idyllic era free of chronic disease, and then portrays Americans as brought low by the inexorable spread of fat and meat into the American diet. It has been repeated so often that it has taken on the semblance of indisputable truth—but this conclusion is based on remarkably insubstantial and contradictory evidence.

Keys formulated the argument initially based on Department of Agriculture statistics suggesting that Americans at the turn of the century were eating 25 percent more starches and cereals, 25 percent less fats, and 20 percent less meat than they would be in the 1950s and later. Thus, the heart-disease “epidemic” was blamed on the apparently concurrent increase in meat and fat in the American diet and the relative decrease in starches and cereals. In 1977, McGovern’s Dietary Goals for the United States would set out to return starches and cereal grains to their rightful primacy in the American diet.

The USDA statistics, however, were based on guesses, not reliable evidence. These statistics, known as “food disappearance data” and published yearly, estimate how much we consume each year of any particular food, by calculating how much is produced nationwide, adding imports, deducting exports, and adjusting or estimating for waste. The resulting numbers for per-capita consumption are acknowledged to be, at best, rough estimates.

The changing-American-diet story relies on food disappearance statistics dating back to 1909, but the USDA began compiling these data only in the early 1920s. The reports remained sporadic and limited to specific food groups until 1940. Only with World War II looming did USDA researchers estimate what Americans had been eating back to 1909, on the basis of the limited data available. These are the numbers on which the changing-American-diet argument is constructed. In 1942, the USDA actually began publishing regular quarterly and annual estimates of food disappearance. Until then, the data were particularly sketchy for any foods that could be grown in a garden or eaten straight off the farm, such as animals slaughtered for local consumption rather than shipped to regional slaughterhouses. The same is true for eggs, milk, poultry, and fish. “Until World War II, the data are lousy, and you can prove anything you want to prove,” says David Call, a former dean of the Cornell University College of Agriculture and Life Sciences, who made a career studying American food and nutrition programs.

Historians of American dietary habits have inevitably observed that Americans, like the British, were traditionally a nation of meat-eaters, suspicious of vegetables and expecting meat three to four times a day. One French account from 1793, according to the historian Harvey Levenstein, estimated that Americans ate eight times as much meat as bread. By one USDA estimate, the typical American was eating 178 pounds of meat annually in the 1830s, forty to sixty pounds more than was reportedly being eaten a century later. This observation had been documented at the time in Domestic Manners of the Americans, by Fanny Trollope (mother of the novelist Anthony), whose impoverished neighbor during two summers she passed in Cincinnati, she wrote, lived with his wife, four children, and “with plenty of beef-steaks and onions for breakfast, dinner and supper, but with very few other comforts.”

According to the USDA food-disappearance estimates, by the early twentieth century we were living mostly on grains, flour, and potatoes, in an era when corn was still considered primarily food for livestock, pasta was known popularly as macaroni and “considered by the general public as a typical and peculiarly Italian food,” as The Grocer’s Encyclopedia noted in 1911, and rice was still an exotic item mostly imported from the Far East.