It drives up prices that they can't afford. There are rumblings in this country about food prices, but not life or death, yet. For the mayority that is. I am sure some are really going to hurt though.
Part of our rising food prices are because of fuel costs making transport and storage higher and higher.
I remember the US having food surpluses back in the day, giving away cheese, etc. And this was happening while third world nations were experiencing hunger (due to many reasons ranging from drought to greedy, evil warlords).
We may just have to do a food for fuel deal for those countries that can trade it. That would theoretically allow us to then re-route our usage and help those less fortunate world-wide from ever-increasing food prices.