Jacqueline Johnson knows what it's like to be shunned because of her weight. In the early 2000s fat activism was edging into existence, and Johnson, a weight studies scholar, was deemed too skinny to take part.

"I tried to join a fat activist group, and I was rejected because I was not of size," she remembers. The movement was gaining momentum as a response to America's growing weight paranoia, and its members, most of them frustrated, plus-size women, were skittish about admitting slender outsiders. "At the time I did understand they were apprehensive that I could be the enemy, trying to filter in and see what they were doing," she says.

Today it's a different story. Johnson, who teaches a course on weight and society at George Washington University, is currently a professor with 25 students of all heights and widths. Her Fat Studies class is one of a handful popping up on campuses across the country, teaching students to think about body size critically, politically, and regularly. But despite such courses' popularity among students, critics worry that such classes emphasize bleeding-heart politics over intellectual rigor.

Most of Johnson's students are female. A few are recovering from eating disorders; their cheeks are hollow and their scrawny arms droop like slack rubber bands. About a quarter of the class is slightly overweight.

All of them have worried about weight at some point in their lives. Some have shown her photos of their former selves: pictures of nearly unrecognizable obese teens. Others merely packed on the freshman 15. Two months into the semester, her few male students have begun to feel comfortable talking about their weight, recounting taunts from childhood and revealing their fears about size. The girls still hesitate to speak up—it always takes them longer to feel secure, Johnson says.

This is the first time that GWU has offered a class devoted specifically to Fat Studies, and its diverse enrollment is an important victory for the subject. Fat Studies scholars say their mission is to promote weight awareness and acceptance among populations of all types. The sociological study of obesity has been creeping into academia for over a decade, often as a subtopic of Women's Studies or Health Sciences. But only recently has weight become a subject of study in its own right. "There would be no Fat Studies if there were no obesity epidemic," says Esther Rothblum, a lesbian studies professor at the University of California, San Diego, and one of the earliest to research the psychology of weight bias.

The Fat Studies Reader, a compendium edited by Rothblum and her colleague, Sondra Solovay, and published to much fanfare in late 2009, is fast becoming a cornerstone of Fat Studies curricula. Its 53 contributors ask the same questions that professors now pose to their students: How is weight perceived in different countries? What do media depictions of larger sizes say about our social priorities? What if there were a "fat gene," and what if we could test for it prenatally?

Spurred by growing national concerns about obesity, many schools now offer undergraduates a place to discuss these questions. Courses that deal with Fat Studies and body image have been taught at schools, including Oregon State University and Rutgers University. Newer still, however, is the growing interest among students and scholars who aren't fat themselves.

"The Fat Studies movement is really important and valuable for smaller people to participate in," says Linda Bacon, a professor at City College of San Francisco and the author of Health at Every Size: The Surprising Truth About Your Weight. "The imperative of thinness in our culture is not based on science, and it causes a lot of pain." From the activist's perspective, thinner students might be the ideal targets of a Fat Studies course, because they're both the victims and the perpetrators of weight stigma.

Bacon, who is slim, says she's been floored by the amount of professional attention her work has received in recent years, particularly from college groups inviting her to speak about size acceptance. "People are recognizing that we need to start talking about these issues, and making it safe for everyone to attend school and feel good in their bodies," she says.

But the presence of feel-good politics in college classrooms concerns some scholars, who worry about promoting acceptance and tolerance at the expense of hard academics. Anna Kirkland, an associate professor of Women's Studies and Political Science at the University of Michigan, is a supporter of Fat Studies, but fears it may lead to social proselytizing rather than serious study. "I'm not interested in areas of study whose main justification is that they're going to advance the situation of some social group," she says. "I mean, that's fine if that's part of the reason. But the main reason should be intellectual interest and energy cohering around a single topic area."

In an article published last year on CampusReform.org, Abigail Alger, a manager at the Leadership Institute in Washington D.C., wrote that the subject is "part of a dangerous dumbing down of liberal education in which the pursuit of knowledge is replaced by frantic social programming and promotion of state programs." The discipline, Alger argued, doesn't encourage open debate, but instead "begins with the end in mind," and brands as a bigot anyone who disagrees.

Members of fat academia have noticed the scarcity of plus-size silhouettes on campus—particularly in exclusive private schools, where Fat Studies is most likely to be taught.

At this point, at least, students seem to be just as much on the fence about the practical value of Fat Studies as the academic community. One senior in Johnson's class who asked not to be named said she thought that Fat Studies was extremely interesting and important, but that it didn't make a big difference in her everyday life. "I personally don't know anyone that's really obese," she said.

Nor, in fact, do many college students. As it stands, most fat activists still don't consider college to be a "weight-safe" environment. Fat undergraduates often experience subtle forms of prejudice that most people tend not to notice, from tiny wooden desks that won't fit their bodies to sidelong stares whenever they visit the student fitness center. Some—like Margitte Kristjansson, a Fat Studies graduate student and alumna of the University of Washington—will voice their concerns to administrators, but many fat students would rather suffer in silence than spotlight themselves by speaking up. "It's definitely harder to be a fat student on campus, when you don't yet know that you deserve respect in the same way that any other student would," Ms. Kristjansson says.

This may explain, at least in part, why there seem to be so few overweight and obese undergraduates enrolled in universities today. Recent studies have shown that body-consciousness can not only hurt academic performance in high school, but can also deter fat students from applying to college, and from receiving adequate help and attention from teachers and college advisers. The exact amount of attrition is impossible to pinpoint, but members of fat academia have noticed the scarcity of plus-size silhouettes on campus—particularly in exclusive private schools, where Fat Studies is most likely to be funded and taught. "The more elite a campus is, the fewer people you will see who are anything but ideal weight," says Rothblum, explaining that in addition to being daunting to fat students, top-tier schools tend to attract applicants from stronger socioeconomic backgrounds, who are much less likely to be overweight.

If marshaling the troops is the goal, then Fat Studies still has a long way to go. Linda Gokee-Rindal, a senior and fat activist at the University of Minnesota Duluth, knows that firsthand: she gave a presentation last month on campus about the politics of body acceptance, and could feel some members of her audience bristle. "I presented it from a fat activist perspective, because that's what I know—and a few people weren't comfortable with that," she says.

That resistance may eventually fade if Fat Studies takes root on campus. But if that's going to happen, slender students may need to turn up the volume of their support for the subject. "For members of any oppressed group, the ones who are allowed a foot in the door are the ones who look as mainstream as possible," says Rothblum. If that's the case, then the fat-exclusive movement that Johnson once faced could be a thing of the past. What fat activism needs now, it seems, are a few small waistlines.

Eve Binder is a senior at Yale University. She currently serves as managing editor for the college blog IvyGate, and has written for Time Out New York and The Deal.