Are you using the carbcounting rule when choosing foods?
Sadly granola bars are often right up there in the same carblevel of bread and icingless cakes. Stuff above 30g carb per hundred grams I try to be careful of.
Have had good results from identifying myself a bit stronger in the fruits and veg aisle ;-)
Personally..? I think the parasites are simply to be expected, and cleaned out with the seasons. I took a lesson from scripture, hyssop is one of those herbs know for being powerfully antiparasitic- and the command to 'eat lamb with bitter (key, bitters are fantastic medicine) herbs' tells a good insight too. :D