Be careful of fructose

This is just a hypothesis, but a pretty good one, I have to say.

Now let's connect the dots. Excessive fructose, certain types of fiber, and wheat cause bacterial overgrowth and H2 production (if you believe the fructose-H2 connection). Elevated H2 causes overgrowth of H. pylori and possibly other pathogenic bacteria in the body. H. pylori lowers stomach acid, causing further overgrowth of bacteria in the small intestine. This causes inflammation and increases the risk for digestive cancers.