Samenvatting

Ghrelin, a peptide predominantly produced by the stomach [1], appears to play an important role in the regulation of food intake. Intravenous infusion of ghrelin stimulates food intake and enhances appetite in humans [2]. In addition, plasma ghrelin concentrations rise gradually before a meal and decrease immediately after eating [3] and [4], suggesting a role for ghrelin in meal initiation. Ghrelin concentrations appear to be correlated with subjective appetite [5], [6] and [7]. Further evidence for a role of ghrelin in meal initiation is provided by the observation that the postprandial decrease in ghrelin concentrations is dependent on energy intake, and is not affected by intake of water [5]. However, in almost all studies investigating pre- and postprandial ghrelin responses, meals were not voluntarily consumed, but on a scheduled basis disregarding the subjects appetite. Such design allows for the possibility that preprandial increases in ghrelin concentrations were part of a cognitive, anticipatory response to upcoming meals.