Okay, so (I don’t know how else to put this) I’ve struggled with anorexia since I was eight years old.
I don’t want to write about it for my CA essay because I don’t want to use an excuse to be let in, but I’ve realized that this has impacted me in everything that I do. I really don’t think I can write an essay without even explaining why, for example, I don’t have a lot of ecs or I’ve been medically withdrawn from school.
What would you all recommend?
I wrote one of my essays about a hardship which was a syndrome I was born with. I chose it because it was one of the most definitive things about me and affected pretty much every aspect of my life. I used the essay as a way to show how I persevered through that medical condition and how it came to be one of the most treasured parts of myself because it taught me determination and compassion even though it kept me from participating in extracurriculars among other things.
Essays about a struggle can shine a lot of light on who you are, but I think that (if you choose to write about one) you should write about the positives and keep anything that could be perceived as a sob story to a bare minimum. My “positive hardship” essay didn’t seem to hurt me as I got into all of the schools I applied to.
I would do some research into the particular subject matter you might write about. I’ve seen a lot of people say that eating disorders and mental illnesses can sometimes raise red flags with schools. This isn’t something I agree with, but I’d look into it. Good luck. 
This is a really bad topic. Writing about mental illness, including eating disorders can get you rejected. With all the backlash schools get about suicide rates, they don’t want to admit people who they think might be unstable. It doesn’t matter if you’ve recovered; to them, you have a risk of relapsing with the pressure of college.
I’m not saying that is how you actually are, but that is how colleges perceive essays like this. Choose a different topic.
And to the above poster, there is nothing inherently wrong with a positive hardship essay dealing with something you are born with. However, eating disorders, depression, and mental illness are not appropriate topics.
Unfortunately, I would avoid writing about this. This will make colleges really weary about accepting you. In fact, writing about an eating disorder can actually hurt your chances at getting into colleges. Most colleges are afraid of accepting a student with a mental illness or eating disorder because of the possibilities of something happening to that student and/or other students on campus. Writing about the negative effects that the eating disorder had on your grades, GPA, ECs, etc. will make colleges even more worried (because they will be afraid of how you’d perform at college). If I were you, I would write about a different topic. Do you have any other ideas for your essay?