The Economist has tracked the price of food since 1854. The magazine's food index has reached its highest levels, ever. Normally, higher prices come when bad harvests limit supply. Not so this time. Grain production is at record levels.Economic growth is pushing food prices higher, as richer people eat more meat. Instead of grain being used for tortillas or biscuits, it is being fed to animals being fattened for slaughter. And, The Economist says, grain is going to produce biofuels. Ethanol is soaking up 1/3 of America's corn harvest.Higher crop prices will help rural areas. Three billion people live in rural areas worldwide, which includes 3/4 of all poor people. Some 2.5 billion are involved in farming. Higher prices are going to help these regions .