Do you remember the food riots from 2008 when food prices soared around the world? You may. Chances are if you're reading this they didn't affect you.
There's an excellent article on the recent riots in Mozambique over cost of living increases, not just food, that should make people start to pay attention. In most developed countries we spend a shockingly small amount of our income on food (for all sorts of reasons) but if you are poor, you are more likely to spend a disproportionate amount of your income on food. And if prices go up dramatically - what do you do?