Exploring the mechanism of within-meal variety and sensory-specific satiation

Food variety has been shown to enhance consumption, and it has repeatedly been proposed that this variety effect might operate by delaying the development of sensory-specific satiation (SSS; a relative decrease in pleasantness of a specific food as it is consumed). This study aimed to advance our understanding of the presumed relationship between SSS and food variety. Participants (N = 30) received two meals on two separate days, one consisting of only two food items (A and B; low variety), and the other comprising six foods (A, B, C, D, E, and F; high variety). Each meal comprised signalled exposure (look-smell-taste-swallow) to a total of 10 bitesize portions: 5 portions of foods A and B in the low variety condition, and 5 portions of A and a single portion of foods B, C, D, E, and F in the high variety condition. Participants tasted 8 food items before and after each meal (i.e., the 6 foods included in the meals plus 2 more unconsumed foods G and H). It was hypothesized that SSS for food A would develop irrespective of overall meal variety, but that SSS for food B would be smaller in the high variety session. The results of this study were in accordance with this hypothesis: strong SSS was present for food A in both meal varieties. For food B, it was present in the low variety meal, but absent in the high variety meal. This indicates that meal variety does not necessarily affect SSS. SSS is strictly determined by degree and timing of sensory exposure to a food. Exposure time should therefore be targeted when developing strategies to influence the development of sensory-specific satiation, which in its turn can affect food intake.