can someone tell me the first signs of anorexia?

i'm worried about my sister; she's lost some weight, not that much where she looks unwell but it's noticable. she's very fussy at meal times.
i'm probably just over reacting but her behaviour is enough for me to be concerened. what are the key signs to look out for?
thanks in advance for your time and comments.

Aside from being fussy at meal times, what else is causing you to be concerned?

The difference between a diet and an ED is quite drastic. A diet is something a person does with their health in mind. This might be losing a few pounds, or changing eating habits so that it better fuels their body. The key thing to keep in mind here is that it's done with the goal of becoming a healthier person.

With an ED, losing weight comes from an unhealthy place. There's little to no concern over the damage being done to the body & mind. It's a way to gain control over life by using food. The person is often seeking acceptance and inner-peace by any means necessary, even if it's negative behaviours driving it.

Listen to what your sister is saying - and what she's not saying - to get a picture of what she's hoping to accomplish with the weight loss. That's your best indicator. There are other signs you can watch out for, like overexercising, disappearing into the bathroom immediately after meals, avoiding situations where there will be food, isolating herself, etc. Those are symptoms of disorder though. If she's truly unhappy and heading toward an ED, she'll need someone to listen to her and hopefully understand why she's doing this.

Good luck, and I hope your sister is fine.