Katie,
A diet of desserts and sugar is not going to do you any favors in battling pouchitis. Bacterial overgrowth is exacerbated by such a diet as it creates more bad bacteria.
I recommend you look at the thread liz started on low Fodmap diet, here:
http://j-pouch.org/eve/forums/...1071921/m/6467017176
And talk to a registered dietician as well.