In my experiences w/the PB cups, I can get away w/eating one serving (5 cups, I believe) w/out having any nasty reactions- granted this serving would be the only thing for the day w/sugar alcohols in it. I made the mistake of eating a whole bag of these suckers once (thanks, TOM ) and I was doing the bathroom dash all night.

Your roomie may want to start out by testing to see how 3-5 cups affect him since they're a YMMV kinda thing. These don't bother me when eaten in moderation, but Russell Stover candies are a BIG no-no for me no matter how many I eat.

HTH-
Nikki