Meal-dependent fluctuations of blood glucose and corresponding endocrine signals such as insulin are thought to provide important regulatory input for central nervous processing of hunger and satiety. Since food intake also triggers the release of numerous gastrointestinal signals, the specific contribution of changes in blood glucose to appetite regulation in humans has remained unclear. Here we tested the hypothesis that inducing glycemic fluctuations by intravenous glucose infusion is associated with concurrent changes in hunger, appetite, and satiety. In a single blind, counter-balanced crossover study 15 healthy young men participated in two experimental conditions on two separate days. 500ml of a solution containing 50g glucose or 0.9% saline, respectively, was intravenously infused over a 1-h period followed by a 1-h observation period. One hour before start of the respective infusion subject had a light breakfast (284kcal). Blood glucose and serum insulin concentrations as well as self-rated feelings of hunger, appetite, satiety, and fullness were assessed during the entire experiment. Glucose as compared to saline infusion markedly increased glucose and insulin concentrations (peak glucose level: 9.7±0.8 vs. 5.3±0.3mmol/l; t(14)=-5.159, p
