Yes, Kat is thin, exceptionally thin, but it's a little strong to say anorexic. Anorexia is I believe a disorder and those who have it don't usually like to expose their bodies, and aren't proud of or even aware of how thin they actually are. Kat appears to not have any of those traits. There are those like Kat who are naturally this thin. I found her stats here. The video is just OK but she is speaking. Check it out.
http://www.laythekat.biz/?page_id=24 Since her stats are metric I converted them. She's 5'6", 105 1/2 lbs, 30A-20 1/2-31 1/2. Considering her very slight frame, 105 lbs if that's correct is fine for her height.