The true culprit: Triticum aestivum, or modern wheat.
Note that I said "modern" wheat, because I would argue that what we are being sold today in the form of whole grain bread, raisin bagels, blueberry muffins, pizza, ciabatta, bruschetta, and so on is not the same grain our grandparents grew up on. It's not even close.
Modern wheat is the altered offspring of thousands of genetic manipulations, crude and sometimes bizarre techniques that pre-date the age of genetic modification. The result: a high-yield, 2-foot-tall "semi-dwarf" plant that no more resembles the wheat consumed by our ancestors than a chimpanzee (which shares 99% of the same genes that we do) resembles a human. I trust that you can tell the difference that 1% makes.
When preparing to go on the road, you can follow Mark's Daily Apple and others like this and eliminate wheat from your diet. Mark recommends eliminating all grains, which is tough in a rice fueled world. http://iperpetualtraveler.com