Michael, when I was diagosed soooo many years ago, my GI only said "if it bothers you then don't eat it" unless he ordered me to a special diet, like a low fat/low residue one. Sounds so unhelpful to others, but I have never excluded anything. I find that it might bother me one time I eat it, and the next it might not. Eggs depend on how they are cooked, etc. Now as far as lettuce, iceburg is awful for me, but darker greens suit my body better, even raw spinach on a subway sandwich instead of lettuce.
That being said, if I am having a bad gut day, I will tend towards things like mashed potatoes and gravy, or a baked potato (no skin)