Here they go again. Americans (at least some Americans, and they know who we are) are living in a gustatory Sodom--pigging out as if there's no Gomorrah. We are--there's no other word for it--obese.

Well, actually there are other words for it, or at any rate there used to be. Remember "stout" and "portly"? "Pleasingly plump," "buxom," "fleshy," "full-figured," "hefty"? Even "overweight" would suffice.

But, no, the U.S. Centers for Disease Control and Prevention insists on "obese"--probably because it starts with the same letters as "obscene"--to impart a hint of immorality to those of us whose tendency is to a certain, well, heft.

Our numbers are soaring, they tell us: from one in eight Americans in 1991 to one in five last year. The obesity rate--30 percent or more above the "ideal" body weight--for the Southeast United States has, during that same period, increased by two-thirds. For Georgia, it has slightly more than doubled.

We're o.b.-ing ourselves to death.

Could I squeeze in a word for the defense?

There are people who claim they like being fat and want the rest of the world to get off their backs. Let them speak for themselves. I speak for those who would like very much to be slim--or at least slimmer--and can't quite seem to make it happen for very long at a stretch.

For us, studies like that of the CDC (which is included in the latest issue of the Journal of the American Medical Association) aren't much help. The advice they offer insults both our intelligence and our experience. Our problem, experts tell us, is that we take in more calories than we burn, so we've either got to start running marathons, go on a starvation diet or contrive some lovely mix of the two.

Why can't they figure out what their chubby friends have known for years: that the tired old calories-in/calories-burned formulation is a crock. Think of the people you know who really are obese--say 100 pounds overweight. I'll almost bet you two things: that they've been 100 pounds overweight for years and years, and that they routinely overeat.

Aha! you say. Doesn't that prove the point? No, it doesn't. The experts would have you believe it's like putting air into an inner tube that has a small leak (representing calories burned). If you put in more air than leaks out, the inner tube gets fat. You knew that.

But you also know this: If you keep putting in more air than leaks out, the inner tube bursts. How many overweight friends of yours have burst in the past five years? Indeed, how many of them have kept getting fatter? Calories-in/calories-burned is one of those notions that, however true in general, doesn't explain what it sets out to explain.

And what might be a better explanation for our stubborn corpulence?

Two things come to mind, not counting the problem of self-control, which keeps some of us eating more and exercising less than we should.

First is the setpoint theory, which I accept as a fact. The body, perhaps for reasons hidden in human history, decides how much fat it wants to retain and then works at defending that decision. Give it more calories and it burns off the excess; give it fewer and it goes on an efficiency kick. If the scientists want to help, let them figure out how to change the setpoint.

The second thing may be more fundamental. Something is wrong with the food we eat--particularly with refined flour and sugar. Or at any rate something is wrong with the way our bodies handle this stuff. Some people who promote this view (I'm thinking of Dr. Gabe Mirkin, the radio fitness, nutrition and sexuality guru) speak of veritable allergies to "converted" rice and white flour. Forget "whole-grain" breads, they say; there's no such thing. The natural stuff that keeps ground grain from being poisonous to those who are susceptible also makes it go rancid shortly after it's ground; that's why processors remove it. But the Mirkins of this world want you to eat such delicacies as wheat berries, which are impossible to find and take hours to cook.

If CDC and the nutrition establishment want to help, they might encourage research on producing nonpoisonous bread and pastas.

And leptin. If the stuff can slim fat mice, why can't scientists harness it for some socially useful purpose like slimming people?

And if they can't do any of these things, then maybe they could just shut up for a while. All these simplistic exercise-and-diet platitudes are worse than useless. They're enough to drive you to your favorite comfort food.