Yesterday, a controversial tweet joking about eating disorders from Lady Gaga -- the most popular celebrity on Twitter, with over 22 million followers -- gave rise to a slew of angry responses. Gaga wrote:

Just killed back to back spin classes. Eating a salad dreaming of a cheeseburger #PopSingersDontEat #IWasBornThisWay — Lady Gaga (@ladygaga) April 10, 2012

It was a surprising statement from Gaga, who has publicly opened up about her struggle with bulimia and urged young women to cultivate healthy body image. During an appearance at a young women's conference in Los Angeles in February, the singer admitted that she was bulimic in high school, and said that she was obsessed with being a "skinny little ballerina."

In response to the tweet, the National Eating Disorder Association staff Twitter account wrote: "Huh? This is the same person who recently implored girls to stop dieting?"

Some of Gaga's fans defended the tweet, saying that it was just a joke and was intended to be ironic. However, the responses were largely negative. For example, one of Gaga's followers tweeted:

@ladygaga why would you even promote a message like that? Disgusting that you'd joke about such a serious illness.. — A. (@AyshaFalco) April 10, 2012

Whether or not the tweet was meant to be funny, eating disorders are not a joke -- in fact, they have the highest death rate of any mental illness. Another pop singer, Demi Lovato, took to Twitter in December to highlight the seriousness of the issue. After an eating disorder joke was made on the Disney Channel show "Shake It Up," Demi tweeted: "Dear Disney Channel, EATING DISORDERS ARE NOT SOMETHING TO JOKE ABOUT." Subsequently, the network apologized and the two episodes in question were pulled from the air.

Miley Cyrus has also taken to Twitter recently to address eating disorders -- but in this case, she was refuting rumors that she might have a problem. She wrote, "For everyone calling me anorexic I have a gluten and lactose allergy. It's not about weight it's about health." In another tweet, she encouraged her fans to go gluten-free for a week. And although many people enjoy good health on a gluten-free diet, it isn't right for everyone -- and critics have questioned Cyrus's decision to dispense health advice to her fans.

What do you think -- is Gaga's tweet offensive, or is it okay if it's just a joke? Tell us what you think in the comments below.

CLARIFICATION: An earlier version of this story indicated that the tweet specifically referenced eating disorders. In fact, it addresses not eating.