This paper follows a previous work that identifies a consistent pattern of increasing materials consumption associated with economic growth, until a certain income threshold is reached [Canas A, Ferrão P, Conceição P. A new environmental Kuznets curve? Relationship between direct material input and income per capita: evidence from industrialized countries. Ecol Econ 2003:46;217–29]. Emphasis is given to the analysis of the economy's metabolism along the period of increasing material consumption, which is associated with transitional economies. Here, an empirical analysis is provided, based on the study of the development of the Portuguese economy, which during the last two decades of the 20th century has crossed this development stage. The mechanisms that induced this transition in material consumption for the Portuguese economy are discussed and the analysis is completed by closing the material balance for the year 2000 in order to understand how material flows have crossed the economy and were transformed in products, stocks, or environmental burdens. It is demonstrated that the development model for this transitional economy corresponds to an increase in materials consumption related to strengthening the infrastructures that are required to improve physical infrastructures. Understanding the metabolism of transitional economies is assumed to be particularly relevant to a global sustainable development, as large emerging economies may be entering in this process.