Effects of fructose and glucose preloads on subsequent food intake.

To determine how the nutrient content of one eating event might affect amount consumed at the next, we evaluated whether equicaloric fructose and glucose preloads differentially influence subsequent food intake. Subjects consumed 50 g of glucose or fructose in 500 ml of water or water alone and were given a "buffet" containing a variety of foods two and a quarter hours later. Subjects in glucose conditions ate, on the average, 252 X 7 calories more than subjects in the water condition, who in turn ate, on the average, 225 X 9 calories more than subjects in the fructose condition. The fructose and glucose preloads did not differentially affect the amount eaten of different types of nutrients (carbohydrate, fat and protein). This study, employing several sensory and cognitive controls, suggests that type of nutrient ingested, in and of itself, plays a role in determining subsequent intake for humans. The data are discussed in terms of possible physiological mechanisms that might account for these effects.