When Tess Holliday, a plus-size model and Instagram influencer, told her audience about her anorexia diagnosis, many of them didn't believe her.

"You are not anorexic! Stop lying to your followers. What's wrong with you, woman? Seriously! This is just wrong," one woman commented.

Even though Holliday is no stranger to criticism—she's often criticized in the media about her weight—these comments still affected her.

"The hate has been overwhelming, but the messages from those of you that felt seen, validated and loved far outweigh the critics," she wrote.

Anorexia that's atypical

Though the vitriol of Holliday's commenters is unwarranted, their confusion may be due to an ignorance of the subject. The terminology for anorexia can be complicated, according to Lillian Rishty, L.C.S.W., a psychotherapist providing mental health services in