DIFFERENTIAL-EFFECTS OF BASE-LINE MACRONUTRIENT PREFERENCES ON MACRONUTRIENT SELECTION AFTER GALANIN, NPY, AND AN OVERNIGHT FAST

Rats display individual patterns of fat and carbohydrate intakes when allowed to self-select among individual macronutrient diets. We invest igated whether these individual preferences in macronutrient selection could be modified by an overnight fast or by two orexigenic peptides, galanin and neuropeptide Y (NPY), which may selectively stimulate fat and carbohydrate intake. Rats were grouped by preference based on the ratio of average baseline fat:carbohydrate intake. fn counterbalanced tests conducted on separate days, saline, galanin, or NPY was infused into the paraventricular nucleus of the hypothalamus and 60-min food intake was measured. When the macronutrient intakes were expressed as percent of total caloric intake, galanin administered into the PVN did not increase fat consumption compared to saline injection in either p reference group. NPY slightly enhanced the proportion of carbohydrate intake, but only in carbohydrate-preferring rats. When all three feedi ng stimuli were compared to baseline preferences, the only condition t hat significantly altered macronutrient selection was an overnight fas t, which augmented fat intake. These data demonstrate that baseline pr eferences for fat or carbohydrate are not significantly modified by ga lanin or NPY but that an overnight fast increases fat preference. (C) 1997 Elsevier Science Inc.