Alliesthesia describes the phenomenon that for the same stimulus, the cued sensory pleasure can be modified according to the internal state. Food sensory alliesthesia (SA) is thus expressed as a difference between pleasures cued by the same food from hunger to satiety states, an experience observed in daily life. Since sensory cued pleasure was intimately linked to food intake, the aim here is to explore what role may be played by the SA in food intake.
In a 5-day experimental protocol, 20 men (20-35 y.o.) were recruited. Olfactory/visual alliesthesia to food stimuli was measured for 14 consecutive meals (4 breakfast, 5 lunches, and 5 dinners). Each alliesthesia measurement consisted of olfactory and visual tests, 15 min before and 20 min after a meal. The olfactory test consisted of 4 olfactory stimuli representing sweet and salty foods for breakfast, or 10 stimuli representing different food types (sweet vs. salty; starter/main course/dessert) for lunch/dinner. Olfactory stimuli were presented in a bottle labeled with a 3-digital letter code. Visual stimuli were corresponding images of olfactory stimuli, presented on screen in front of the subjects. For each stimulus, participants rated sensory pleasure, wanting to eat, familiarity, and disgust using a line scale displayed on the screen. Our results show that participants had relatively stable alliesthesia from meal to meal during their 5-day stay. Moreover, independent of the level of hunger or satiety, the amplitude of alliesthesia is rather a characteristic of an individual's sensory function. The results of this first study on consecutive measures of SA suggested that, unlike the previous view that the SA may be involved in instantaneous food intake control, the SA in this following study manifests rather as an individual's sensory response profile, which might determine a habitual food intake pattern characterizing an individual food intake behavior.
Funding: Centre national de la recherche scientifique (CNRS)