It's not only the collapse of the stock market that has the upper classes biting their fingernails. In the last couple of weeks, the low-fat, high-carb way of life that was central to the self-esteem of the affluent has been all but discredited. If avarice was the principal vice of the bourgeoisie, a commitment to low fat was its one great counter-balancing virtue. You can bet, for example, that those CEOs who cooked the books and ransacked their companies' assets did not start the day with two eggs over easy, bacon, and a side of hash browns. No, those crimes were likely fueled by unbuttered low-fat muffins and delicate slices of melon. Grease was for proles.

But as we learned in a recent cover story of the New York Times Magazine, there never was much to support the dogma that the low-fat approach will make you slim and resistant to heart disease. In fact, the American epidemic of obesity coincides precisely with the arrival of the anti-fat dogma in the 80s, accompanied by a cornucopia of low-fat cookies, cakes, potato chips, and frozen pot roast dinners. Millions of Americans began to pig out on "guilt-free" feasts of ungarnished carbs-with perverse and often debilitating results, especially among those unable to afford health club memberships and long hours on the elliptical trainer.

I have confirmed these findings with my own scientific study, which draws on a sample of exactly two: myself and Jane Brody, the New York Times health columnist and tireless opponent of all foodstuffs other than veggies and starch. It was Brody, more than anyone, who promoted the low-fat way of life to the masses, producing columns, from the 80s on, with headlines like "Our excessive protein intake can hurt liver, kidneys, bone," "Carbohydrates can help you lose weight," and " 'Chemicals in food less harmful than fat."

As she revealed in a 1999 column, Brody was herself raised on a high-carb, low-fat diet of "shredded wheat, oatmeal, challah, Jewish rye, and bagels," the latter presumably un-blemished by the customary smear of cream cheese. I, meanwhile, was raised on a diet that might strain even an Inuit's gall bladder. We ate eggs with bacon or sausage, meat for lunch, and meat again for dinner, invariably accompanied by gravy or at least pan drippings. We buttered everything from broccoli to brownies, and would have buttered butter itself if it were not for the problems of traction presented by the butter-butter interface.

And how did Brody and I exit from our dietarily opposite childhoods? She, by her own admission, was a veritable butterball by her 20s-a size 14 at only 5 feet tall. I, at 5' 7" weighed in at a gaunt and geeky 110.

Fast forwarding to the present: We assume Brody is now admirably trim, if only because of her exercise regimen, since otherwise she wouldn't have dared to promote the low-fat dogma in person. For my part, I no longer butter my brownies, perhaps in part because of Brody's tireless preaching. But the amount of fat she recommends for an entire day-one tablespoon-wouldn't dress a small salad for me or lubricate a single Triscuit. I still regard bread as a vehicle for butter and chicken as an excuse for gravy or, when served cold, mayonnaise. The result? I'm a size six and have a cholesterol level that an envious doctor once denounced as "too low." Case closed.

And if that doesn't convince you, Dr. Barry Sears, inventor of the high-protein "zone" diet, has been arguing for years that there's a solid medical explanation for why the low-fat, high-carb approach is actually fattening. A meal of carbs-especially those derived from sugar and refined flour-is followed by a surge of blood sugar, then, as insulin is released in response, a sudden collapse, leaving you often light-headed, cranky, headachy, and certainly hungrier than before you ate. Fats and protein can make you fat too, of course, if ingested in sufficient quantity, which is to say that gives you the feeling that you've actually eaten something.

We have, in other words, been massively misled for decades, while those who dared raise a voice in favor of protein and fat-like Dr. Atkins of the eponymous diet-were branded as charlatans and enemies of the public health.

But facts don't seem to matter when a major dogma so flattering to the affluent is at stake. In the last couple of decades, the low-fat way of life has become an important indicator of social rank, along with whole grain-as opposed to white-bread and natural fibers versus polyester. If you doubt this, consider the multiple meanings of "grease," as in "greaser" and "greasy spoon." Among the nutritionally "correct" upper middle class people of my acquaintance, a dinner of French bread and pasta has long been considered a suitable offering for guests-followed by a plate of bone-dry Biscotti. And don't bother asking for the butter.

What has made the low-fat dogma especially impervious to critique, though, is the overclass's identification of low-fat with virtue and fat with the underclass's long-suspected tendency to self-indulgence. Low-fat is the flip side of avarice for a reason: Thanks to America's deep streak of Puritanism-perhaps mixed with a dollop of democratic idealism-ours has been a culture where everyone wants to be rich, but no one wants to be known as a "fat cat." We might be hogging the Earth's resources and tormenting the global working class, the affluent seem to be saying, but at least we're not indulging the ancient human craving for fat. So the low-fat diet has been the hair shirt under the fur coat-the daily deprivation that offsets the endless greed.

I wouldn't go so far as to blame the financial shenanigans of the last few years on Jane Brody, but clearly there is a connection. The long-term effects of a low-fat, low-protein diet are easy to guess: a perpetual feeling of insatiety, a relentless gnawing, and a hunger for more. No doubt, for many thousands in the low-fat, high-earnings crowd, money has become a substitute, however unfulfilling, for dietary fat.