Children can definitely have eating disorders. It can be seen on children who refuse to eat and on those who console themselves by eating and become fat. It is unusual for them to vomit in order to keep thin.
Babies increase their weight threefold during their first year. In infancy they only increase their weight by a few kilos a year and their appetite is no longer so ravenous. Some parents get nervous when a child eats so little and there is a risk that they will try to persuade it to eat more. When a child notices that it can influence the parent's mood by eating or not eating, it has obtained an effective instrument of power. There is then a risk that eating will be drawn into a power struggle and the child will not eat primarily in order to satisfy its hunger or stop eating because it is satisfied. Comfort eating of junk food has become more usual and this can cause fatness and ill health. Tired parents feel unable to resist a child's nagging about it. Even if the parents have prepared a wholesome dinner in the evening the children may be so satisfied by junk food that they can't eat proper food and anyway, according to the children, junk food is more fun and tastes better. However, they haven't the knowledge about nutrition which is needed to guide them. Many teenagers despise school food and buy junk food instead.