To determine the effects of calories and sweetness perception on intake, fasted normal weight subjects drank a preload sweetened with sucrose (1.1 g/kg) or L-asparthyl-L-phenylalanyl-methyl ester (Aspartame, 0.011 g/kg), or with no added sweetener. Sweetness perception of the load was reduced in half of the subjects by oral application of Gymnema sylvestre extracts. One hour after the preload, a meal of snack foods was presented and amounts of nutrients eaten were calculated. Subjects whose perception of sweetness had been decreased for the preload ate less total and sweet calories than did those with normal perception. Calories did not affect intake. The effect of calories and perception of the load was also assessed on variables presumed to correlate with satiety. Sucrose pleasantness ratings were not related to calories, perception or intake. Subjects' estimates of the amount of milkshake that they would drink if given the opportunity to do so and hunger ratings were related to overall intake and carbohydrate intake, respectively. The findings indicate that hedonistic aspects of taste are of greater importance than calories in determining short term intake.