IN HIS NEW comedy, "The Nutty Professor," Eddie Murphy plays Sherman Klump, a kindly 400-pound scientist who invents a serum to make himself thin. He gulps down a "DNA restructuring" formula tested only on rats and metamorphoses into Buddy Love, an obnoxious womanizer who is as brash as Sherman is timid. When the potion wears off, Buddy, of course, balloons into Sherman again.
Audiences have reacted with side-splitting laughter, but many Americans probably won't be entertained.
Although Sherman, as Buddy, gets his revenge on a fat-basher at one point and the movie ends with a heartwarming speech by Sherman about the importance of being yourself, it is preceded by one fat joke after another, including repeated scenes of Sherman and his large relatives eating like pigs.
"A lot of the stuff is not even funny," says Carolyn Schmidt, president of the Chicago chapter of the National Association to Advance Fat Acceptance, a 5,000-member advocacy group based in Sacramento. Murphy "clearly doesn't understand how hurtful the world can be to people who are large. Somebody as big as [Sherman] certainly didn't get that way by sitting around and eating all the time. They got that way by being born with a different metabolism.
"When the poor man is trying to get in a chair in the dean's office -- that's every large person's fear -- the audience were all laughing at that. They were also laughing when he was shown at home listening to some music that he liked and moving around. Everybody does that. But they thought it was hilarious, like a buffoon or clown went home and acted like a human being.
"It was good that the thin character didn't play to the stereotype that life is wonderful when you lose weight, but whole parts of it played to the stereotype of what people imagine life is like for someone who is fat. It's ridiculing people, not ridiculing beliefs about fat people.
"I was pretty uncomfortable walking out of the theater, wondering if someone was going to say something to me, given the reactions of the audience."
Esther Rothblum, a professor of psychology at the University of Vermont, who studies the social consequences of discrimination, says that "being fat is the last area where people feel they can be quite biased, quite discriminatory in a way that they can't be with other groups."
Others, more bluntly, call it "the last safe prejudice." Activists say that those who are larger than average face discrimination in employment, education, housing and access to medical care and insurance.
William J. Fabrey, a thin man who writes a quarterly media column for Radiance: The Magazine for Large Women and helped found the National Association to Advance Fat Acceptance in 1969 to do something about the discrimination his fat wife had to face, says that "the media -- particularly Hollywood and the tabloids -- reinforce stereotypes [about fat people].
"The large actor or actress is often used as a sight gag to get a quick or cheap laugh."
But Fabrey says that "a few Hollywood writers are beginning to see that fat people are people like everyone else." He cites the 1994 film "What's Eating Gilbert Grape" as an example of progress. The sensitive story of a small-town teen-ager burdened with responsibility for his younger, retarded brother and single, housebound, obese mother was improved, according to Fabrey, the input of large-size actress Darlene Cates, who battled to keep her character from being portrayed as "a sideshow freak."
"The fact that producers were willing to listen to her says something."
In a society obsessed with looks, especially thinness, fat people face discrimination and cruelty on a daily basis that no other segment of society would tolerate.
It goes beyond dirty looks and smirks. Some people feel free to make rude comments to those who are large, to take items out of their shopping carts, to offer unsolicited advice about losing weight, sometimes anonymously, or even worse, to make ugly noises as they pass on the street.
"There's this myth that if we really wanted to, we could be thin," says Sally E. Smith, the association's executive director. "That the reason we're fat is that we're out of control, we're gluttonous. That if we only exercised a little willpower we could be thin."
These anti-fat attitudes continue even in the face of growing evidence that fat people can't help it. A panel of experts convened in 1992 by the National Institutes of Health to look at success rates of weight-loss programs concluded: "There is increasing physiological, biochemical and genetic evidence that overweight is not a simple disorder of willpower, as is sometimes implied, but is a complex disorder of energy metabolism."