I think you probably hit the nail on the head. I imagine your doc just wanted to let you know that if you start to struggle with weight in the future, that rather than choosing unhealthy behaviors, that Wellbutrin could be an option. However, I know that some anti-depressants also help to combat the thoughts/biochemistry behind anorexia. I'm not sure whether or not Wellbutrin is one of the meds that can do that. Probably that question would be best directed to a pharmacist or your doctor.
I thought it was odd too but her main issue was that this may be a healthier way to loose weight. We did not discuss seizure risks and I wonder what the link is between eating disorders, Wellbutrin and seizures.
So far I haven't lost any weight, it has been about a month now since I started the meds. The only thing I really notice is that I am shaky and have a tendency to tap my toe or pen when I am sitting just to keep something moving. The Dr. wrote this off as being more aware of anxiety due my mood stabilization.