Americans may fret that Wheat Thins cost 15 percent more than a year ago but in poor nations, such price hikes aren't taken lightly.

In Haiti, four people were killed in protests last week over a 50 percent rise in the cost of food staples in the past year. From Egypt to Vietnam, price rises of 40 percent or more for rice, wheat, and corn are stirring unrest

The food price hikes may not be temporary, according to the UN World Food Program, which sees long-lasting causes, such as spreading deserts and more demand for grain-fed meat.