Most of it goes to feed and fatten livestock. A lot of it also goes into food ingredients for humans and pets. They can extract hundreds of things from corn. The scientists get giddy talking about it.
https://www.ers.usda.gov/topics/crops/corn-and-other-feedgrains/feedgrains-sector-at-a-glance/
40% of US corn crop goes into making ethanol. Not a small amount at all.