Deprivation alters rats' flavor preferences for carbohydrates and fats.

The effects of food deprivation on rats' preferences for the flavors of different macronutrients were investigated. To minimize postingestive influences on flavor preferences, brief test sessions (30 min) and calorically dilute (0.08 kcal/g) solutions or suspensions were used. The findings revealed that whereas nondeprived rats preferred sucrose (2%) to hyrolyzed starch (2% Polycose), food-deprived rats strongly preferred Polycose to sucrose. Deprived rats also acquired a preference for a cue flavor paired with Polycose, while nondeprived rats preferred a sucrose-paired cue flavor. Food deprivation also caused rats to switch their preferences from sucrose to corn starch, and from sucrose to corn oil. Food deprivation did not, however, alter the rats' preference for Polycose over corn starch, and it blocked, but did not reverse, their preference for Polycose over corn oil. Taken together, the findings indicate that food deprivation enhances the preference for palatable nonsweet nutrients (Polycose, corn starch, corn oil) over a sweet nutrient (sucrose). This effect was specific to food deprivation; water deprivation did not reverse the rats' preference for sucrose to Polycose.