So she did have an eating disorder after all
http://www.etonline.com/news/175721_alexa_vega_opens_up_about_emotional_elimination_on_dancing_with_the_stars_and_eating_disorder/
I know it was speculated on here a lot around 2007 that she might have an eating disorder...she did lose a lot of weight during that time and ended up being a bit too skinny for a while. However it's only now that she's admitted to battling bulimia for six years.
Then again, by the time she lost a lot of weight and people were wondering about eating disorders she had already been bulimic for at least three years and was still bulimic for another two or three years after she gained the weight back.
So either her eating disorder was very bad at around that time or her weight loss was unconnected to her eating disorder.
Either way, I wish her the best.