The purpose of this paper is to explore the role of changes in the sectoral structure of world demand for the welfare implications of trade and international specialization. A two-countries two-goods model with external economies of scale is presented. Demand develops according to non-linear Engel-curves with phases of expansion and saturation. The economies of scale are exploited by international labor division where the two countries specialize on different sectors. A country which specializes on the production of the income-inelastic good may suffer losses from international labor division and trade.