Could this possibly be Anorexia Nervosa?

One of my friends, she's a healthy girl. She used to eat normally, but I've noticed since she's in my cl during the lunch period, all she ever eats is salad, gs, or strawberries. I know this isn't Anorexia yet, but I feel like she watches what she eats way too much. I always see her reading the amount of calories in everything she eats. I also found a journal in her room the other day where she writes down exactly what she eats and how many calories it has. Sometimes all she does is drink water or gatorade throughout the entire day or she'll have really small meals or just not eat during the day. She lost a lot of weight due to her Anorexia back in our freshman year (about 30 pounds) of high school. She's gained some of that weight back now and I think that she thinks that she needs to lose that weight again. Could these be signs of Anorexia again? She's always been small and skinny, but she's got a lot of muscle on her because of the sports she plays. (track, tae kwon do, etc) I just don't know if she could possibly be going through Anorexia again or if this is completely normal and she's just trying to lose some weight. I just want to help her get through it because she's fine the way she is and I don't think she needs to watch what she eats like the way she does.