Moderator duty first: You appear to have posted essentially the same post in 2 different sections, which clogs up the board. I've deleted one and had the one with a tiny bit of extra info that the other one didn't have reside in the p2 area, which is the appropriate place. I left a "shadow" in the p1 area that redirects you to the p2 area when reading this topic.
As an advice-giver, I'm a little confused. 2/8ths is the same as 1/4. 1/4 sounds like too large of a portion, unless it's a pretty small pizza. 1/8 is probably an appropriate size.
I wouldn't say it's normal to experience cramping when first incorporating a grain/starch or fruit (not "carbs," since there are carbs in a bunch of p1 foods, too). It could be that you've uncovered a gluten sensitivity by removing those foods for a period of time, or sometimes grain products can have weird fibers added to pump up the fiber count that can cause cramping. Inulin comes to mind, as do the gums and things like cellulose fiber. I had one tortilla brand do that to me.
-- food lists, portion guidelines, etc.
SB since Nov '03
Goal: major weight loss (50+ lbs) & good health
Reached Jan '05!