In developing countries, the past decades have seen a marked demographic shift from rural to urban. By the year 2000, 40% of the population of the Third World will live in urban areas. We have limited specific knowledge of the similarities and differences in diet, nutrition status, and health effects of diet and lifestyle between the traditional rural populations and the emerging urban poor. Such information will be useful for basic descriptive information as well as for assistance in the design and execution of health and nutrition projects for the urban poor.