GM (genetically modified) food is food which has been produced using genetic engineering to modify some genetic characteristic of the food. In most cases foods are modified to promote higher yield, faster growth, disease resistance or for some other economic purpose. Some genetic modification is purely for production purposes. GM food is very controversial, with some experts claiming that the genetic modifications make the food difficult or impossible to metabolize fully, unlike natural foods. The production of GM food is considered by some as a potential means of meeting demand for food from a much larger global population in the future.