Posted 1/25/2016 1:06 AM (GMT 0)
Like @gumby said, it's a little different for each of us. And what we can eat in a flare as opposed to in remission is very different. For me, gluten and lactose are fine, but super high-fibrous foods are a bit painful, like popcorn or spinach. But I can eat apples, grapes, and broccoli (sparingly). I just try not to overdo it with the fiber (like all fruits all day or something). You can even get constipated in remission from not having enough fiber.
However, when I am flaring (and most people who are flaring, so active diarrhea, pain, etc.) you want to go to bland, mild diet. Google the BRAT diet, for example. Some people will even need just a straight liquid diet (although that's for extremes).
Some things will trigger some minor symptoms, but not actually cause a flare. Chocolate is a big one - it'll make me gassy and more than a handful or two of M&Ms in a sitting might even cause a bowel movement and some cramping, but it goes away and doesn't lead to a flare.
I would suggest as the prednisone tapers down, to keep a food journal for several months. Keep track of what he eats and what symptoms/bowel movements he has (I know that's so hard to talk about). That could help you see a pattern of what is upsetting his stomach specifically. If it's hard to tell, you could try an elimination diet, where you take out all but very basic foods, and slowly add types of foods in every few days (similar to starting on baby food as infant to make sure there aren't any allergies).