my sister may be going anorexic

Okay, so my little sister who is 11 has always been a good weight, not too thin not overweight, and I've always been thin. Last month we went to the pediatrician and I weighed 11 pounds more than her and I'm 7 or so inches taller than her. The doctor said she was perfectly healthy at 4'9 and 86lbs but she compares herself to me and thinks she is fat. Recently, she hasn't been eating anything sweet like she usually does, has been wanting to go running a mile of hills with me which she used to think was insane. She hasn't been eating a lot, today I asked her everything she ate and it wasn't even 1200 calories. Some may say im hypocritical but i have been eating almost 2000 calories a day for a while to be healthy. Also, today she was in her bikini and I could see her ribs pretty well. Usually I can't see them with her. Im very concerned that she could become anorexic because she thinks she's so fat. Something's wrong.... Does anyone have any advice to change her mind and get her eating right?

Talk to your sister. Let her know that eating too little and being underweight is just as bad and dangerous as being overweight. Tell her that she is beautiful just the way she is and that she doesn't need to lose weight at all. Kind words and communication will go a long way.

^this

Talk to your mom... There is little you can do .. Voice your concern that could make your mom take action.. Eat with your sister make it so you see what she eats and she sees you eating