Carbophobia, the most recent in the centurylong series of food fads to wash over the American table, seems to have finally crested, though not before sweeping away entire bakeries and pasta companies in its path, panicking potato breeders into redesigning the spud, crumbling whole doughnut empires and, at least to my way of thinking, ruining an untold number of meals. America's food industry, more than happy to get behind any new diet as long as it doesn't actually involve eating less food, is still gung-ho on Low Carb, it's true, but in the last few weeks, I can report some modest success securing a crust of bread, and even the occasional noodle, at tables from which such staples were banned only a few months ago.

Surveying the wreckage of this latest dietary storm makes you wonder if we won't someday talk about a food fad that demonized bread, of all things, in the same breath we talk about the all-grape diet that Dr. John Harvey Kellogg used to administer to patients at his legendarily nutty sanitarium at Battle Creek, Mich., or the contemporaneous vogue for "Fletcherizing" -- chewing each bite of food as many as 100 times -- introduced by Horace Fletcher (also known as the Great Masticator) at the turn of the last century. That period marked the first golden age of American food faddism, though of course its exponents spoke not in terms of fashion but of "scientific eating," much as we do now. Back then, the best nutritional science maintained that carnivory promoted the growth of toxic bacteria in the colon; to battle these critters, Kellogg vilified meat and mounted a two-fronted assault on his patients' alimentary canals, introducing quantities of Bulgarian yogurt at both ends. It remains to be seen whether the Atkins-school theory of ketosis, the metabolic process by which the body resorts to burning its own fat when starved of carbohydrates, will someday seem as quaintly quackish as Kellogg's theory of colonic autointoxication.

What is striking is just how little it takes to set off one of these applecart-toppling nutritional swings in America; a scientific study, a new government guideline, a lone crackpot with a medical degree can alter this nation's diet overnight. As it happened, it was an article in this magazine two years ago that almost singlehandedly ushered in today's carbophobia, which itself supplanted an era of lipophobia dating back to 1977, when a controversial set of federal nutritional guidelines ("Dietary Goals for the United States," drafted by a Senate committee led by George McGovern) persuaded beef-loving Americans to lay off the red meat. But the basic pattern was fixed decades earlier: new scientific research comes along to challenge the prevailing nutritional orthodoxy; some nutrient that Americans have been happily chomping for years is suddenly found to be lethal; another nutrient is elevated to the status of health food; the industry throws its marketing weight behind it; and the American way of dietary life undergoes yet another revolution.

If this volatility strikes you as unexceptionable, you might be interested to know that there are other cultures that have been eating more or less the same way for generations, and there are peoples who still rely on archaic criteria like, oh, taste and tradition to guide them in their eating decisions. You might also be interested to know that some of the cultures that set their culinary course by the lights of pleasure and habit rather than nutritional science are actually healthier than we are -- that is, suffer a lower incidence of diet-related health troubles. The "French paradox" is the most famous such case, though it's worth keeping in mind the French don't regard the matter as a paradox at all; we Americans resort to that word simply because the French experience -- a population of wine-swilling cheese eaters with lower rates of heart disease and obesity?! -- confounds our orthodoxy about food. Maybe what we should be talking about is an American paradox: that is, a notably unhealthy people obsessed by the idea of eating healthily.