Conditioned sweet-paired stimuli elicits potentiated feeding in humans

Eating is not only controlled by endogenous metabolic signals but also by the presence of learned food-cues in the environment that potentiate consumption even in the absence of immediate nutrient needs. While ‘cue-potentiated’ feeding is well characterised in non-human animal (e.g., rat) models, detailed experimental analysis in humans is lacking. As a preliminary test of whether learned food-related associations could initiate and maintain overconsumption, 45 participants, identified during pre-tests as sweet-likers, completed a disguised training procedure where novel visual cues were paired with either a sweet taste or a neutral (artificial saliva) taste, with additional distracter cues and tastes used to disguise these associations. Participants were then placed in a free-consumption situation during which either the sweet-paired or the neutral-paired cues were presented (tested between-groups). Participants presented with food and drink stimuli that were labelled with a sweet-paired cue ingested significantly more than those given the same products labelled with the neutral-paired cue. This increased consumption of both sweet and savoury foods suggests that cues potentiated feeding by activating a more a general motivational state rather than a sensory-specific expectation. There was no evidence that participants’ level of explicit knowledge of the cue-taste associations affected consumption. Taken together, these data provide the first evidence that visual stimuli associated with a palatable sweet taste lead to a generalised increase in intake, suggesting that learned associations between environmental cues and food availability could be an important feature of the obesogenic environment.