Quoted from Science on a Sphere:
Not all cropland is used for producing food directly for people. A lot of the food crops grown are actually used as feed for animals. This map shows which regions produce crops that are mostly consumed directly by humans (in green), which regions produce about the same amount of human food and animal feed (in orange), and where most of the crops are used as animal feed (in red).
As discussed in 2 Billion More Coming to Dinner, the conversion of crops to meat is not particularly efficient (in the case of cattle, for example, about 30 pounds of feed are needed to grow a single pound of beef), so as global demand for meat rises, cropland devoted to growing animal feed will have to increase proportionately. What effect will this have on the cost of meat, crops, and our diets?