The reason most likely to trigger eating disorder in teens is their self-consciousness of their body shape.
Although the issue of discrimination on body shape is less severe nowadays, the trend of being slim or thin is still promoted by the media,for example,in the Kpop industry,almost every pop star has to be very thin.
Some then become hyperaware with their body and weight, either wanting to look better or is afraid of being discriminated of looking fat or chubby.
Some would then use unhealthy diet or fasting to cut the weight, eventually causing eating disorder such as anorexia nervosa(constantly not eating enough) or bulimia (force themselves to throw up what have been eaten).