This is an issue that is almost impossible to get information about until you are competing for the program. Every coach in the country will say that if a runner has an eating disorder they won't race, there is no way to tell if they follow through with that until you get there.
Most coaches promote and atmosphere of general health, in that they won't poke or prod anyone toward developing an eating disorder, but I would say the majority of the programs in this country are ill-equipped to deal with an ED if it should occur.
There is simply no way to know upfront what the atmosphere of the team is when it comes to healthy eating. That likely won't become apparent in one visit either, you just need to pick the school you think is right for you.