On closer inspection, though, this isn't your typical prom, nor are these your typical promgoers.

Just look at what's happening under the rainbow-balloon trellis, where Theresa Meire, a chubby 29-year-old woman dressed in a tuxedo T-shirt and blue jeans, is selling raffle tickets. For five dollars, people can get a "body wrap," and women happily come up to let her circle their breasts, or waists, in tickets. The catch: the greater the women's girth, the greater their chances of winning one of the evening's prizes, including sex products, a wine sleeve, or the title of Prom King or Queen. One woman, breasts spilling out of a bright red evening gown, buys four wraps and emerges with 10 feet of tickets.

Welcome to My Big Fat Queer Prom, a celebration of body size and sexuality. Here, the words "fat" and "queer" aren't pejoratives, they're statements of purpose. The prom-attendees' ages range from the teens to the fifties and the crowd is composed almost exclusively of women. Everywhere you turn, there is soft flesh—large tummies and rolling cleavage—cheerfully on display. For some of the women, who've spent lifetimes ostracized for their size, or their sexual orientation, or both, tonight is an opportunity to experience the prom they never had. For others, it's just a chance to have fun.

On the dancefloor, Sharonmelissa Robertson, wearing a top made of duct tape, grinds with Miasia, a burlesque dancer. Robertson made her shiny outfit, held together by string, especially for this party. Justin Timberlake blares on a boombox. The crowd jumps and heaves.

My Big Fat Queer Prom is a benefit for NOLOSE, formerly known as the National Organization for Lesbians of Size. For NOLOSE members, fatness is an identity to be redeemed, celebrated, and flaunted. Let the rest of America panic over the obesity epidemic. For this new wave of radical queers, fat activism just makes sense. "Previous to the last 10 years there were other struggles," says Chelsey Lichtman, a member of the Fat Femme Mafia performance group. "Now, fat is another identity that queer is making OK."

It's common knowledge that Americans are getting fatter. We're reminded of this by an endless parade of media reports and medical statistics. According to the most recent survey by the Centers for Disease Control, two-thirds of Americans are overweight. Of those, one-third are fat enough to be fully obese.

Even as official concern about obesity grows, the so-called "size acceptance" community has organized its own countermovement. Since the '60s, groups like the National Association to Advance Fat Acceptance have been fighting "fat-phobia" and advocating for fat people's rights. In 2001, San Francisco passed legislation making it illegal to discriminate based on body size, and in academic settings, fat studies—a close relative of queer studies—are gaining popularity. In 2006, the first Fat and the Academy Conference at Smith College attracted nearly 150 participants.

Lesbians, in particular, have good reason to concern themselves with fatness. In a study published in the June issue of the American Journal of Public Health, researchers from Boston University and the University of Western Ontario claimed that lesbians are more than twice as likely as straight women to be overweight.

"We don't have the data to find out why that is," says Ulrike Boehmer, an assistant professor of social and behavioral sciences at Boston University and an author of the study. Lesbians seem to be at higher risk for a wide range of health problems, ranging from depression to polycystic ovarian syndrome and some forms of cancer. But Boehmer says it's hard to get funding for research into what's causing the diseases or their effect on lesbian health.

Surely some, if not most, of the obesity among lesbians is the direct result of eating too much and exercising too little. And what of it, say the fat activists. As an outgrowth of the feminist movement, lesbian activism has often questioned conventional body politics, embracing butchness and fatness more openly than straight culture. "The fat movement is an extension of the queer movement," says Lichtman. "It's about fighting for the rights of people who live outside the bubble of normal."

But while many fat, hirsute gay men have found acceptance in bear culture, queer women are now only beginning to organize a female equivalent. The bear community, which rejects the conventional gay male aesthetic of buff, hairless bodies, has traditionally favored a scruffier, heavy look. Bears have a thriving bar scene—with bear bars like the Dugout in the West Village and Big Lug on Avenue A—but the subculture operates primarily as a social group.

"Gay male communities that center around fatness tend to be apolitical," says Kathleen LeBesco, Marymount Manhattan College professor and author of Revolting Bodies? The Struggle to Redefine Fat Identity. "Whereas lesbian groups tend to be highly politicized."