The door to her daughter's room closed with an exclusionary click, leaving behind three pictures of Charlie's Angels, two bumper stickers and a Magic Marker sign that read: "Do Not Come In. This Means You."

The two girls wanted privacy. They were talking about the subject that had been declared off-limits, verboten.

No, not that one. In this house, sex was an open-door topic. Sex could be spoken about in public. "Fat," however, had recently been forbidden. "Fat" could now only be whispered about.

One last sentence had escaped the room, like air from a can, before it had been sealed. "Do you think I'm fat?" one girl had asked the other. From the kitchen, the mother had shrieked, "Good Gawd . . ." And so now, she was left to stew.

The girls were not, as you might expect, teenagers. By then, all conversations seem to be divided into three parts: weight, hair and boys. But these two were fourth-graders! They were 9 going on 15.

Furthermore, they were not chubbies. They were hummingbirds. THey cartwheeled through life. Like gas guzzlers, they used up calories at a rate of 3,000 an hour. If they didn't idle at the stop signs long enough, they would disappear.

The only excess weight they carried between them was in their book bag. And, of course, in their culture.

The two lived in the land of Dieters, where weight weighed heavily on people's minds, like sin. They were surrounded by advice on how to lose pounds and find happiness. They were told that gaining weight is like giving yourself acne, a kind of do-it-yourself unpopularity. They were informed on all sides that obesity was a lack of willpower . . . a psychiatric problem . . . a moral lapse.

The only thing the adults in their native land watched more than their weight was their television sets - inhabited, of course, by the emaciated.

Her niece had recently told her, in a very matter-of-fact voice: "Elizabeth Taylor let herself go and now she's fat." They virtually all agreed that "fat is bad." They all rated strangers and friends on the scales of their disapproval.

But now, they had taken to checking each other for signs of creeping middle-aged flab. It drove the woman berserk and, in a frenzy, she had driven the subject underground.

But when she wasn't foaming at the mouth, she knew what had happened. Another threshold had been lowered. Today, 14-year-olds were having sex, and 9-year-olds were worring about weight. Obsessions flow downhill.

The adults around them who were not actually dieting were at least considering it. So the children had come to assume that fat was a grownup preoccupation. Dieting had become a rite of passage to adult life. It was the training bra of this generation. The woman wanted to ride through the land screaming, "Anorexia nervosa is coming!" She predicted an epidemic of adolescent half-starvation on the horizon. She was totally convinced that an entire generation of children would hit 13 and, instead of wiring their teeth straight, they would wire them shut.

As she was fantasizing the worst, the door opened and the girls cartwheeled into the kitchen asking for ice cream. The woman beamed. She wanted to pour fudge sauce into their hands. Perhaps they had a few good years left, she thought, scooping huge balls of mocha almond into their bowls.

For one brief ecstatic moment, she thought about joining them for a sundae. Then she remembered. She was on a diet.