Beyond expectations: the physiological basis of sensory enhancement of satiety

Consumption of high-energy beverages has been implicated as a risk factor for weight gain, yet why nutrients ingested as beverages fail to generate adequate satiety remains unclear. In general, consumers do not expect drinks to be satiating, but drinks generate greater satiety when their sensory characteristics imply they may be filling. These findings challenge traditional bottom-up models of how gut-based satiety signals modify behaviour to suggest that beliefs at the point of ingestion modify gut-based satiety signalling.

Healthy volunteers (n=23) consumed four different beverages, combining an overt sensory manipulation (thin, low sensory (LS) or thicker and more creamy, enhanced sensory (ES)) and covert nutrient manipulation (low energy (LE), 78 kcal; high energy (HE), 267 kcal) on different days. Effects on satiety were assessed through rated appetite and levels of glucose, insulin, pancreatic polypeptide (PP) and cholesystokinin (CCK) recorded periodically over 90 min, and through intake at an ad libitum test lunch.

Intake at the test lunch and rated appetite were both altered by both the sensory and nutrient manipulations, with lowest intake and greatest suppression of hunger post-drink in the ESHE condition. Insulin increased more after HE than LE drinks, and after ES than LS drinks, whereas PP levels were higher after ES than LS versions. CCK levels only increased after the ESHE drink.

These data confirm acute sensitivity of satiety after consuming a drink both to the sensory characteristics and nutrient content of the drink, and suggest that this may be, at least in part, due to top-down modulation of release of satiety-related gut hormones.