The actress referred to her journals to create her hit New York stage show "Yeardley Smith: More," the World Entertainment News Network reported Monday.
"The cliche is you can change the outside as much as you like, but the inside more or less remains the same, and you are no more or less a better person for that," she explained.
In the show, the actress confesses she began dieting when she was age 9 and battled bulimia at 14.
Smith said the problem worsened when she moved to Los Angeles and tried to make her body fit the leading lady mold, thinking that would lead to more work.
Unable to get her body to look the way she wanted, she underwent liposuction surgery.
"Ultimately, I don't regret having the plastic surgery," she said. "I do regret feeling as though if I didn't have it, I couldn't go on for another day."