Creamy…smooth…decadent. We all know how fat feels on the tongue. But is it time to elevate fat from a rich texture to a taste? NPR reports that a group of scientists are pushing for fat to be classified as the sixth primary taste.
A new paper by a group of sensory scientists in Australia makes the case for fat as a primary taste. Russell Keast, the lead author, tells NPR that “taste is a chemical function.” His team cited five criteria that make a taste different from a feeling, including the existence of a chemical stimulus, the existence of pathways that let our brains translate those stimuli and “physiological effects” once our taste buds have been activated.
Fat meets most of those criteria, including the stimulus (fatty acids) and the pathways (via known taste receptors). So why hasn’t fat already taken its place among bitter, sweet, umami, sour and salt tastes? It turns out that humans are pretty bad at perceiving what fat tastes like when it’s not rancid. That leads some scientists to theorize that it’s not a taste at all, but more of a sensation.
But Keast’s team thinks otherwise. They note that fatty acids can activate taste bud receptors, causing people to sense the presence of fat even when they can’t identify its taste. And, given that rodents and people who are less sensitive to fat taste are also predisposed to obesity, they think that fat’s time as a taste is on the horizon.
If fat were to take its place among the primary tastes, it would be the first addition since umami, the savory flavor associated with foodss like seaweed and amino acid-rich soy sauce and cheese. But though Keast’s team predicts it will be only five to ten years before fat is classified as one of the primary tastes, other scientists aren’t so sure. Nutrition scientist Richard Mattes tells NPR that since fat isn’t easily perceived as a flavor, it’s different from the other primary tastes:
If we confirm that fat is a basic taste quality, it's the equivalent of saying chartreuse is a primary color. It changes our basic understanding of what taste is.