dont know if this will help but...
i cant have sugar. fruit is ok tho.
honey i cant do and maple syrup blows my knees up quick and big time!
yes some things that test ok can be a prob due to other aspects i.e asparagus. has inulin that some cant handle.
i also have trouble with artificial sweeteners and food dyes.
i would say stop the metamucil? sounds like the culprit. if u eat other things with sugar and dont have a prob then maybe amount of sugar matters OR other things in the product.