1. Plants defend themselves from predators (i.e. animals, humans, insects) via chemical warfare. These chemicals can and do disrupt the gut of the predator to dissuade them from consuming the plant. At least in humans, 70-80% of immune cells are contained in the gut. Many genetically modified plants are engineered to produce more of these gut disrupting chemical defense compounds to be more resistant to predators.

2. A study by the CDC estimates that 80% of Americans have glyphosate in their urine. Glyphosate is an antibiotic proven to be disrupting to gut bacteria. Crops are being genetically engineered to allow for more and more glyphosate exposure because the weeds are growing increasingly resistant to it, requiring even more glyphosate - which in turn runs off into our water supply. It's a positive feedback loop as nature abhors monoculture. Monocrop agriculture is fundamentally unsustainable