The connection between overweight and health risks has been known since the beginning of the 19th century. In order to define overweight, the "body mass index" (BMI) in kg/m (2) was introduced.The present study evaluates the quantity and quality of the published literature available, and its changes over the years. Basic bibliographic methods and recent visualizing techniques were used in order to analyse and categorise research in the field of the BMI. The data were extracted from "ISI Web of Science" by Thomson Reuters beginning from 1900 to 2008 by defined search terms.There are 63,845 articles on the subject available. It shows, that the number of annual publications is increasing continuously, starting in 1972. The bibliometric methods and the application of density equalising maps reveal global research productivity and citation activity with emphasis on the USA.The present study supplies a first bibliometric approach to visualise research activity in the field of BMI. Furthermore, it provides data that can be used for the identification of research clusters and to locate regions where more research needs to be done. Despite the controversial discussion, the analysed data suggest that the BMI is still an important, simple, and inexpensive measure for the assessment of the nutritional status that comes to a worldwide use.