Rats appear to have two different carbohydrate tastes, a sweet taste for sugars, and a "polysaccharide" taste for starch and starch-derived polysaccharides. The present study explored the possible functional significance of this dual taste system by comparing the effects of food deprivation and insulin treatment on the appetite for sucrose and Polycose. Food deprivation (24 h) produced comparable increases in the 5-min and 30-min intakes of Polycose and sucrose (1-8%) solutions in adult female rats. Polycose and sucrose intakes were also increased to a similar degree by insulin injections (1 unit/kg) during brief (3-min) one-bottle tests. In brief two-bottle tests, however, insulin treatment tended to shift the rat's preference from sucrose to Polycose. Chronic treatment with insulin increased the long-term intake of 30% Polycose and sucrose solutions, with the effect being more pronounced with Polycose. These findings demonstrate that energy deficit states enhance the appetite for Polycose as much as or more than the appetite for sucrose.