Starch content of ordinary foods associatively conditions human appetite and satiation, indexed by intake and eating pleasantness of starch paired flavours

After one experience with the effects of a disguised augmentation of the starch content of a food eaten early in a meal, there was a decrease in the amount of that food eaten subsequently at meals on a menu that included the same flavours. Starch eaten late in the meal did not establish this suppression of intake of the item having a flavour paired with the extra starch, but did strengthen its subjective satiating effects, i.e., increased the reduction in rated pleasantness that occurs on eating most foods. When taken as snacks, the same starch-augmented foods had a direct satiating effect, similar in size to the satiating effect of believing the food to be high in calories: 20 min after ingesting the starch, both the amounts the consumer wished to eat and the ratings for pleasantness of foods on a separate menu were reliably lower than after the control snack. Associative conditioning of the pleasantness of eating the flavours of snacks augmented with starch also occurred, resulting in a pattern of acquired responses that accounted for the previously observed differentiation of meal sizes: that is, a conditioned decrease in the pleasantness of a starch-associated flavour was observed when that flavour was eaten and tested in relatively replete states, and a conditioned increase in its pleasantness was observed when training and testing were carried out during normal hunger. Thus, at least parts of both the appetite for a food and the satisfaction from it can be learned from experience of the after-effects of the food’s starch contents.