In reply to henwardian:
Physical signs:
Significant weight fluctuations
Stomach complaints or pain
Changes in bowel habits
Changes in menstrual regularity, stopping menstruating or missing periods
Feeling dizzy, weak, or tired. Fainting.
Changes in skin and hair
Emotional signs:
Preoccupation with weight and/or calorie counting to the extent that it disrupts other activities
Being preoccupied with body image/size/shape (may focus only on a particular part of the body)
Limiting the repertoire of food eaten, including restricting whole categories of food, having lists of safe and unsafe food
Performing rituals around eating food
Not eating in social situations or being very private about eating
(From a short course about recognising disordered eating I did when I was coaching gymnastics)