For some time now, a significant minority of the American population has considered bread suspect. Atkins and South Beach were down on bread long before the contemporary anti-gluten frenzy came into vogue. These days, everything from pizza to makeup is available gluten free, and no less a scientific authority than Jenny McCarthy has claimed that eliminating gluten from her son’s diet helped “cure” his autism. The problem is that gluten is everywhere, and avoiding it requires intense and sustained scrutiny. Dinner rolls are deeply suspect, of course, and so, for that matter, are dinner parties.

But if the anti-gluten craze is new, fear of bread is not. For the last century and a half of our history we’ve been intermittently spasmed by fears over bread. In the 1920s and ‘30s, a bread panic called amylophobia swept the land, boosted by a leopard-skin-wearing diet guru named Bernarr MacFadden who toured the country and called bread the “staff of death.” Throughout the last century, fierce debates over white versus whole wheat pendulummed the nation’s eating habits back and forth. With the rise of industrial bakeries, white bread was evidence of scientific progress, its very whiteness visual proof that it had been made by machines rather than dirty hands. But within decades, white bread was accused of causing deformities. “The whiter the flour the more rapidly it leads to the grave,” one expert observed. And through it all, just as now, whether or not one ate bread was as much a public as a personal act, declaring one’s social status and indeed, one’s moral rectitude.

Two new books trace the questionable science and vested interests behind bread fears and bread boosterism. As Aaron Bobrow-Strain makes clear in his epically well-researched White Bread, our culture’s tendency to focus what we as individuals put in our mouths often goes along with classism and xenophobia. Just as whole wheat acolytes pity white-trash white-bread eaters, and gluten-free converts showcase their discipline through vegetables and lean proteins, so, too, did turn-of- the-century crusaders attempt to spread the gospel of good food to less enlightened masses.

Between 1890 and 1930, Bobrow-Strain writes, Americans transitioned almost completely from homemade bread to store bought bread—and specifically to bread made in large factories. Hygiene fears were a major reason. The emerging understanding of germ science led pure food crusaders to preach against the dangers of mother’s kitchen, which couldn’t hope to achieve the level of cleanliness of a large bread factory, nor the heat necessary to kill the “yeast germs.” “You and your little oven cannot compete,” one newspaper article informed women after the turn of the century. Scientists and food reformers also warned against mom-and-pop bakeries, whose reputation for substituting cheap substances like chalk and alum was further undermined by the presence of so many swarthy immigrant workers, whose hygiene was considered suspect.

White bread, untouched by human hands and carefully wrapped for hygienic transport, became a symbol of purity. As a doctor named Woods Hutchinson put it in McClure’s Magazine in 1906, with unsubtle racialism, “No race ever yet ate black bread when it could get white; nor even brown, yellow, or other mulatto tint.” And then: “White flour, red meat, and blue blood make the tricolor flag of conquest.”

But during the ‘20s and ‘30s, the nation was gripped by panic over white bread. A wave of experts with questionable pedigrees began warning about white bread’s nutritional content, harkening back to the teachings of 19th-century ascetic Sylvester Graham, who believed that refining wheat undermined God’s intent. (Graham had a number of interesting theories, including that consumption of meat, seasonings and rich foods lead to rampant masturbation.)

Dietician and radio show host Alfred W. McCann claimed that 400,000 children a year were sent to “little graves” because they were raised on white bread. Food pundits said that white bread could cause blindness and disfigurement. A 1912 article in a journal called “Life and Health” made the dubious claim that in countries where there was no white bread, there was no cancer. Bobrow-Strain writes that white bread was implicated in a slew of illnesses including “diabetes, criminal delinquency, tuberculosis … rheumatism, liver disease, kidney failure …” White bread’s fortunes sunk, and bakers, who preferred white flour in part because it was cheaper to mill and could be stored longer, were beside themselves.

As with the contemporary fad for gluten-free living, there was a germ of truth in the backlash against white bread. Few nutritionists would now question the superiority of fiber-rich whole grain breads over pale, spongy Wonder Bread. By the same token, contemporary concerns over gluten arise from a real problem: Celiac disease, a genuinely dangerous condition, afflicts as many as 1 in 133 people. Celiacs who consume gluten can experience diarrhea, vomiting, weight loss, arthritis, and worse. The less serious problem of gluten sensitivity, which is a newer clinical category and harder to diagnose, appears to cause abdominal troubles, fatigue, and headaches.

But less is known about how gluten affects the rest of us, and in pockets of our culture our concerns have crossed the line into ridiculous. “Something you’re eating may be killing you, and you probably don’t even know it!” read a 2010 story on gluten in the Huffington Post. According to an ABC News report, researchers believe that only “5 percent to 6 percent of those who claim they have gluten sensitivity actually have it.” Meanwhile, celebrities and athletes have embraced the gluten-free lifestyle as a means toward thinner bodies and faster times, and as with so many diets before, the message of restrictive eating is plain: That which I don’t eat makes me better than you.

White bread’s fortunes would reverse with as much fickleness (and as little basis in science) as they had fallen. Basically, the food industry got proactive. In a new book Fear of Food, historian Harvey Levenstein details the reversal of one influential white bread skeptic, chemist and vitamin scholar Elmer McCollum, who had once called white flour wholly “deficient” in nutrients. McCollum was gradually co-opted by the enemy, first by agreeing to advise the National Bakers Association, and then by signing on as a spokesman for General Mills. Soon enough he was railing against “food faddists who have sought to make people afraid of white-flour bread.” In 1930, bread producers pressured the USDA to formally endorse the wholesomeness of white bread.

By the ‘40s, bread makers had started enriching their products with vitamins, and, in response to wartime anxiety about the fitness of Americans, ad campaigns suggested that eating enriched bread was not just good nutrition but a patriotic duty. Wonder bread, with its promise to build strong bodies, was mainstream and middle class before it became shorthand for everything bland and processed in the ‘60s and ‘70s, and, eventually, shorthand for poverty and apathy. White Bread informs us that whole wheat bread sales exceeded sales of white bread for the first time in 2009.

Bobrow-Strain, who teaches food politics at Whitman College in Washington state, is deeply concerned with how our good intentions go awry when we let food fears and food fads separate us from one another. He suggests that, again and again through the last century, food crusaders have chosen language and tactics that reinforce social hierarchies instead of dealing with the underlying reasons why rich and poor eat differently—including the availability of inexpensive, healthy food, and wages that make it possible to buy this food.

He also points out how often our choices about what we eat get mixed up with our perceptions of what is moral. “Today,” Bobrow-Strain writes, “showing interest in healthy eating is an essential piece of the performance of eliteness.” That’s why celebrities call their crash diets “cleanses,” and vegetables are confused with virtuousness. Food is shorthand for values. I’m sure I’m not the only person who’s felt self-conscious buying artificially-flavored cake mix, as if the purchase of such a non-nutritious food made me a less wholesome person. Instead of bringing us all together, the dinner table is the means by which we define ourselves against everyone else.