not sure what "inffu" means ... maybe a typo or cell phone autocorrect?

with me all my alters were different than me some had problems I had and some had problems I did not have. but because it was one whole body that everyone lived with in, the best way to handle health problems and mental health problems was to treat me the body person. this way treatments would not counteract each other leading to a dangerous possibly life threatening situation.

in other words to address the eating disorder of me and those alters with eating disorders I the body person (or in your words the host) entered an eating disorder treatment program, this taught me and those that took control because of eating issues what was healthy for us, and how to follow treatment provider approved diet plans rather than starving/ purging and other eating disorder ways.

one thing about my system... it was dissociative related meaning I was diagnosed with DID because my alters would take control when ever I the body person had my dissociative symptoms due to triggers (Triggers can be good or bad, they are anything that caused me to feel any strong emotions, even things like feeling frustrated because I did not know how to do something so an alter took control to do that for me)

anytime I felt my dissociation symptoms an alter took control to handle that. one time I asked my therapist how did the alters know when to take control and who to take control. she said that with me there was a sort of filter which was my dissociation symptoms and the alters sense of agency (their job, purpose, reason for being created, how much control they had and more)

based on this filtering system what worked for me would "filter down" to the right alters. so my treatments also helped the alters with the same problems that I was having with eating disorders.

maybe you can talk with your treatment providers, they can help you to find treatments that will help both you and the alters that have eating disorders like mine did.