The curvy singer/actress spent years auditioning for jobs but was regularly turned down by casting agents, who told her she needed to lose weight if she wanted to work in Hollywood.
In a taped segment for U.S. series This Is How I Made It, an emotional Riley teared up as she told how the pressure to be thin took its toll on her, and she even considered giving up her dream.
She says, "Hollywood is a very hard place to be in. It really is. Being the person I am, you know, the size I am, being a woman, being a black woman, there's not a lot of roles for us.
"After I did (2002 Tv movie) St. Sass, I kept on auditioning. I was being offered the girl who sits in the corner and eats all day, the girl who committed suicide because she was fat. I never wanted to play a character that hated herself. I wanted people to know that those aren't the only roles for people like me, normal girls.
"Going to the auditions and having the casting director say you need to lose a little weight, I didn't understand why people couldn't accept me for who I was. And the rejection started wearing on my self-esteem."
The 26 year old made a name for herself after landing the role of Glee's Mercedes Jones in 2009, and she now feels proud of her figure.
She adds, "I'm not going to conform, and hurt myself, and do something crazy to be a size two... I'm a healthy person. I have great friends around me that are positive. That's the key to life, (sic) is make your own path, set your own rules. There is no set rule, no set look, no set anything."