Like The Root on Facebook. Follow us on Twitter.

Subsequent reports have produced even more stereotype-shattering results. A 2009 study (pdf) showed that not only were African-American girls 50 percent more likely than white girls to be bulimic, but girls (black or white) from the lowest income bracket were also significantly more likely -- 153 percent more -- to experience bulimia than their peers in the wealthiest group.

"We had also held the popular conception that bulimia was more common among girls from white, middle- to high-income families, so the results surprised us," Michelle Goeree, a lead researcher in the study, told The Root. It made more sense after the researchers realized that many insurance policies don't cover the doctor's visit where eating disorders are diagnosed, thus throwing off the documented numbers. "If two girls suffer from bulimia nervosa, but one is from a low-income family and the other from a high-income family, which girl is most likely to be diagnosed if it often requires a visit to the expensive psychiatrist?"

A 2011 study published in the Journal of Adolescent Health also confirms that bulimic behavior is more common among African-American youths. In fact, young people from various racial backgrounds, including Asian Americans and Latinos, were found to practice extreme food-related behaviors, such as vomiting and laxative abuse, two to 10 times more often than their white counterparts. 

Causes and Effects

The field of research further challenges conventional wisdom that says black women always love their curves, celebrating thickness on the strength of a community that is more accepting of different body types. Gayle Brooks, an African-American psychologist and clinical director of the Renfrew Center -- an eating disorders treatment center in Coconut Creek, Fla. -- says that black women feel increasingly pushed to change.

"In our society, the more you achieve and make in the world, the more you're pressured to acculturate," she told The Root. "Oftentimes, young African-American women want to fit in, and feel they have to let go of some of the cultural norms that might have protected them in the past." Yet Brooks went on to say that it's usually not a drive for thinness at the heart of eating disorders among black women. It typically involves exposure to some type of trauma, from physical abuse to poverty, racism or a struggle with ethnic identity.

"The biggest misconception is that this is only about being thin," says Armstrong, noting that most people with bulimia are either a normal weight or slightly overweight. "I don't believe that's the first reason. It comes from some kind of trauma and a need for control -- you don't just wake up one day and decide to throw up."

In Armstrong's case, the trigger was being raped by an uncle when she was 12. Having grown up in a fatherless Brooklyn, N.Y., household, she says that being assaulted by her single male role model left her feeling worthless. "I had no other men in my life who loved me to help me see, 'This person is messed up.' For me it became, 'I'm messed up.' " Studies show that roughly 60 percent of people with bulimia have suffered sexual abuse.