Used to be obese,now she is mad skinny?

I had this friend tht had a huge butt and really fat legs most likely thunder legs or thighs whatever you call them. She left school 2 years or maybe 1 year and a half but now she has really skinny legs. Her legs are now like chopsticks :P yeah they're mad skinny. What happened to her? Like what are the possibilities she had a liposuction? I just wanna know if I could get skinny legs aswell :P I can't ask her becz she doesn't have social networking at all