Fast food is one of the world's fastest growing food types. It now accounts for roughly half of all restaurant revenues in the developed countries and continues to expand there and in many other industrial countries in the coming years. But some of the most rapid growth is occurring in the developing world, where it's radically changing the way people eat. People buy fast food because it's cheap, easy to prepare, and heavily promoted. This paper aims at providing information about fast food industry, its trend, reason for its emergence and several other factors that are responsible for its growth.