I just found out my sister has an eating disorder. Could I have one too????

Apparently its called 'binge-ing' where she eats late at night shes been noticeably underweight the past couple of years. Is there a chance I have one too? I have a really limited taste in foods and I tend to eat a lot when Im really hungry, in fact I could almost eat a whole pizza (8 slices) if im really starving, and sometimes I eat one or two huge meals a day without snacks. Im not obese nor skinny- Im about 6'0'' 185-190. Thanks!!!!!!

Usually when people 'binge eat', they go to the bathroom and vomit the food so that they do not gain weight. It is not a nice thing. Perhaps that's why she is 'noticeably underweight' as you say.

You do not appear to be the same since you simply seem to have a healthy appetite or you love to eat, and plenty, too. But your weight is normal for your height, and you don't mention any ailments or abnormalities.

You did not say if she had just one meal per day, only that she ate late at night, so it is a little difficult to determine anything further.

She does need help. though, and support.

It's not a disorder, it's a weakness.
No, eating disorders are not hereditary. I think you are ok...but be cautious of other addictive behaviors (drinking, smoking, shopping, gambling..)
What you have does not even remotely sound like an eating disorder. It sounds like you have "skinny genes". If you were purging (making yourself throw up after eating) or starving yourself or grossly over eating and overweight then yes.