When a confectioner leaves a gooey chocolate masterpiece out to dry and harden, its flavor is left unchanged. But chomping down on the hardened sweet manifests in a different experience than chewing the softer variety. And as scientists come to better understand the underlying causes of these distinctive experiences, they're discovering that the differences can fool our minds into underestimating our calorie intake.
There's more to our mouths than just taste buds. Our tongues and palates are moist hotspots for oro-sensory stimulation—feelings known as oral haptics, or mouthfeel, that can profoundly shape the eating experience. (The sight of food can also affect this experience, as can the feel of it in our hands—though in the West, we tend to shovel straight into our mouths using cutlery.)
Scientists recently set out to determine how mouthfeel can affect the perceived number of calories in a sweet. In a paper published last month in Journal of Consumer Research, they say they were driven to investigate this phenomenon because of "the role of mindless eating in contributing to the obesity epidemic" and misguided "calorie estimations and perceived healthfulness" of certain snacks.
There's more to our mouths than just taste buds. Our tongues and palates are moist hotspots for oro-sensory stimulation—feelings known as oral haptics, or mouthfeel, that can profoundly shape the eating experience.
The researchers fed a bunch of undergraduates candy to test how the hardness, smoothness, and chewiness of chocolates affected perceptions of caloric content.
When the students sampled chocolates that were produced by the same manufacturer and differed only in hardness, they wrongly concluded that the softer sweets contained more calories. When they were told to focus on the chewing process for the sweet, the perceptions of higher caloric content of soft chocolates were amplified. And after trying otherwise identical chocolates with smooth and rough textures, the students concluded that rougher textured alternatives were more healthful.
The findings aren't just applicable to esoteric tongue science. These misperceptions can actually make us fatter.
For the researchers' final experiment, students were told they were taking part in trials for a marketing company—a firm that had gratefully provided them with unlimited brownie bits to eat while they watched advertisements. Students were given Styrofoam cups full of brownie bits, some of which were soft and gooey while others had been hardened by drying. Some students were told to estimate the caloric content of the brownies; others received no such direction.
The researchers found that the students tended to eat more of the soft brownies. Unless, that is, they were asked to estimate the number of calories in the snacks, in which case they were more likely to eat the harder ones.
(Chart: Journal of Consumer Research)
Dipayan Biswas, a University of South Florida marketing professor and a study author, said food companies appear to understand this phenomena, "which is why we see so many food products in the marketplace that vary on haptic dimensions"—such as smooth and crinkle-cut fries.
The real danger foods? The scientists warn that granola bars, trail mixes, and cereals can all seem in our mouths to be more healthful than they really are.