I switched to whole grains and that seems to have helped a lot; and I also must watch the amounts I eat of them and dairy products too, as it seems to be a combo thing going on. Cooked veggies are not a problem as they dissolve pretty well becuz they are soft from the cooking process.
Since I made these other changes, I can now eat veggies and salads with no problem. I really think the amount is more important -- I measure everything now ie 1 cup coleslaw OR 1-2 cups romaine mixed salad with lite dressing of choice (which is Ranch for me). It may take some time before you can eat raw veggies again though.
We eat pasta (1 cup cooked) as before, but now have more whole grain pastas, which we like just as well; just cook it a few minutes longer. (I am trying to use up all of the regular pasta we have by alternating each time with whole grain or other fiber-rich pastas; and all we buy now are those two types).
We also eat brown rice mixed equally with whole grain white; sometimes adding in some wild rice for a change. We also eat beans, and small, new potatoes with their skins on, varying our menu each day.
I can have a treat of ice cream as long as I only have about 1/2 cup on occasion. I eat lower sugar fruit and sometimes bake apples or a lite fruit crisp. I buy Source Yogurt in those small containers too. I rarely have a problem now, but find that I have to watch fatty, greasy foods now as my body isn't used to eating them anymore.
I also have some days with the opposite problem now; so have to make sure that I drink enuff water and have at least 1-2 tbl of good oil/fats each day to keep my system moving well.
I find that having the snacks helps my stomach move the food thru my system better which is a problem we have inherited, as our food doen't leave our stomachs fast enuff; it only moves on when we eat our next snack or meal ...
My sister tried meds for that, but after awhile the meds don't work anymore, so it seems that eating small amounts, more often, is a healthier solution.
Don't forget that STRESS can ascerbate the problem even more; which means, it can make IBS even worse, so you need to try to find ways to destress your life as much as possible too.
Hope this helps you in some way.