OH god don't, ragged, she may be reading this.
Actually, she is quite typical of adult anorexics, who often incorporate and manage anorexia within a quasi-functioning life for years on end. Which you can't do if you're like teenagers, ricocheting down to 4-5 stone at the rate of knots. I was anorexic for many, many years, and never stopped eating and never got down to a visibly dramatic level. No, I kept to 1000 calories a day for several years, which kept me at a weight of just over 6 stone (I'm 5'9"). I was just about able to keep working, and just about able to keep out of hospital.
The very fact that I didn't get dramatically thin meant that I could go on for years (some people stay this way for life). It put my organs under incredible strain. Also, the longer anorexia goes on the harder it is to cure. A teenager who spends several months at a shockingly low weight has far better prospects than an adult who has been anorexic for years.