Internal and external determinants of eating initiation in humans

The influence of two internal variables (gender and nutritional state as measured by subjective hunger) and one external variable (either visual pre-exposure to a food stimulus or variation of the visual quality of the stimulus) on appetite for pizza in general or for a specific pizza, was studied in an experiment with 129 male and 225 female adult subjects, which were distributed in almost equal ratios over four sessions per day. They rated their hunger, their appetite for pizza (before and after visual presentation of the product) and their desire to eat a slice of any of four pizza varieties varying on visual characteristics. It was shown that appetite for the item pizza increased with hunger and with pre-exposure to the food, but that these two factors did not interact. Appetite for a specific pizza was influenced by its visual quality and by hunger, both factors acting independently. Compared to hunger, gender, the second internal factor, exerted a lesser influence. Furthermore, the reported appetite for a certain food item proved to be a good predictor of actual eating behaviour.