I have difficulty gaining weight but never an issue eating and especially staying hydrated. I just got over my first bout of pouchitis and lost a couple of pounds, but gained it right back once the symptoms disappeared. The best thing would be to get yourself back on track with food and fluids. I had to be treated when I was hospitalized during a flare for dehydration and malnutrition and am doing everything I can to not deal with that again. You may want to consider a nutritionist/dietitian if you haven’t already. Good luck!