Purely anecdotal but I suffer from Crohn's Disease and the only thing that really helped was Soylent. I can't eat solid food and since starting Soylent I have experienced much lower occurrences of symptoms.
For example, have you tried Ensure?
Also, how long has it continued to help? I ask because it is fairly easy to find interventions that help a chronic illness, but then stop working or accumulate prohibitive adverse effects after a few months.