Hey, I have been a type 1 for 21 years and I was diagnosed with gastroparesis about 2 years ago. I know how painful and uncomfortable it can be. The best thing to do is keep a food diary and also document when you get pain so that you can start to see what bothers you. I know that with me it is things like whole grains, barley and pulses, brown wheat products and some white flour products. One of the things that drives me crazy is that white bread from one place might be fine but not from another and you don't know till you've eaten it.
I would recommend doing some research about it. You might want to see a dietician as they can advise on what to do because a lot of the lovely low GI foods that us diabetics are supposed to eat can cause you problems. Also perhaps talk to your diabetic nurse they may have some advise.
Hope this helps.
Amy