Manipulating perceived amount eaten does not impact sensory specific satiety

The aim of this study was to explore whether sensory specific satiety (SSS) is affected by perceptions around the amount of food that is consumed. To dissociate the effects of the perceived amount and the actual amount consumed, a 2 × 2 design was employed. This produced 2 congruent conditions, in which the same amount was seen at the outset and then subsequently consumed (300 ml or 500 ml), and 2 incongruent conditions, in which 300 ml was seen but 500 ml was eaten or vice versa (20 participants in each condition). In incongruent conditions, food was covertly added or removed from a bowl using a hidden peristaltic pump. Half of the participants received tomato soup as the ‘eaten’ food and custard as the ‘uneaten’ food and half received the converse. Measures of pleasantness and desire to eat were recorded at baseline and 0, 20, 40, and 60 min after meal termination. As in previous studies, the eaten food decreased in pleasantness and desire to eat significantly more than the uneaten food (evidence for SSS). There was also evidence that actual amount influenced the degree of SSS. By contrast, SSS was unrelated to the perceived amount consumed. This is the first study to dissociate cognitive and oro-sensory influences on SSS in a healthy population. This result is consistent with previous research showing SSS is intact in amnesic patients and supports the notion that SSS is a relatively low-level phenomenon based on habituation.