Cortical Response to Fat Taste

Abstract

We sense fat by its texture and smell, but it is still unknown whether we also taste fat despite evidence of both candidate receptors and distinct fat taste sensations. One major reason fat is still not recognized as a basic taste quality is that we first need to demonstrate its underlying neural activity. To investigate such neural fat taste activation, we recorded evoked responses to commercial cow milk products with 0.1%, 4%, and 38 % fat via high-density electroencephalography (EEG) from 24 human participants. The experimental design ensured that the products would only be discriminable via their potential fat taste; all stimuli were carefully controlled for differences in viscosity, lubrication, odor, temperature, and confounding tastes (sweetness, acidity, and "off-taste") and were delivered directly onto the tongue using a set of computer-controlled syringe pumps. Advanced topographical pattern analysis revealed different neural activation to the milk products 85-134 ms after stimulus onset, which, as expected, best discriminated the two milk fat extremes (0.1% and 38% fat). Notably, this time period has previously been shown to also encode basic taste qualities, such as sweet or salty. By adding to the evidence of cortical fat taste processing in response to staple food, our finding not only substantiates that we taste fat but also highlights its potential relevance during our everyday lives with possible large-scale impacts on motivational eating behavior to explain overconsumption of energy-dense foods.

Keywords: electroencephalography; fat taste; gustatory evoked potential; oleogustus.