You might ask your doctor about Life's Abundance Weight Control Formula, which is a holistic food. If you decide to purchase, message me through here, and I can send you the link, but please ask your vet first before purchasing.
Since she's already on a prescription diet for weight control (w/d formula), ask your vet about changing the prescription to the I/D forumula. That one is specific for pancreatitis and other GI problems. You might want to post on the Ask a Vet Forum here at Med Help. Dr. Cheng volunteers her time, so it's free, and she's great with both western veterinary medicine as well as holistic Chinese medicine. I'm sure she'll have some good suggestions for you. :-)