Using an extended model to calculate the level of growth consistent with the behavior of the balance of payments and the simple structure equation proposed by Thirlwall, a growth rate larger than the observed rate was estimated. This is explained by the accumulated surplus in the commercial account and the balance of payments, and because prices do not adjust demand in international trade. It was found that the income elasticities of demand are variable and are found to be affected by industrial and trade policy. It is concluded that the supply (Krugman) and demand (Thirlwall) approaches are complementary.