Why is it often difficult to tell if a person has an eating disorder?

Because they'll try to hide it.

That's because part of them knows that what they're doing is unhealthy and so they don't want people to know.

Because if they aren’t anorexic yet they would hide it because say they were eating food at school with friends they could say they are going toilet and throw it up in toilet but try and not make a sound and they could also say to there parents that they ate there food or the parents could see that they bought food and the parents wouldn’t know that they threw it in the bin also in pe they might cover theirselves or go into a toilet to get changed and they maybe wore a jumper and leggings or trackie bottoms to cover legs and arms and if they are anorexic just not show their body to anyone