The creaminess of fat-rich foods such as ice-cream and salad dressing appeal to many, but new evidence indicates that some people can actually "taste" the fat lurking in rich foods and that those who can't may end up eating more of those foods.
In a series of studies presented at the 2011 Institute of Food Technologists annual meeting, scientists said research increasingly supports the notion that fat and fatty acids can be tasted, though they're primarily detected through smell and texture. Those who can't taste the fat have a genetic variant in the way they process food, researchers said, possibly leading them to crave fat subconsciously.
"Those more sensitive to the fat content were better at controlling their weight," said Kathleen L. Keller, a research associate at New York Obesity Research Center at St. Luke's Roosevelt Hospital. "We think these people were protected from obesity because of their ability to detect small changes [in fat content]."
Keller and her colleagues studied 317 healthy black adults, identifying a common variant in the CD36 gene that was linked to self-reported preferences for added fats such as butters, oils and spreads. The same variant was also found to be linked with a preference for fat in fluid dairy samples in a smaller group of children.
Taste a driving force or eating
Keller said it was important to confine the study sample to one ethnic group to limit possible gene variations. Her team asked participants about their normal diets and how oily or creamy they perceived salad dressings with fat content ranging from 5 to 55%.
About 21% of the group had what the researchers called the "at-risk" genotype, reporting a fondness for fatty foods and perceiving the dressings to be creamier than other groups, she said.
"It's an evolving science," said Jeannie Gazzaniga-Moloo, a spokeswoman for the American Dietetic Association and nutrition instructor at California State University in Sacramento. "However, it's something that needs more exploring because we certainly do know that taste is a driving force in what people eat."
Other abstracts presented at the meeting, held in New Orleans, elaborated on the "fat-tasting" theme. Functional brain images suggest that an individual's perception of the "pleasantness of fat texture" shows in two brain regions, the orbitofrontal cortex and the pregenual cingulate cortex, according to Edmund Rolls, of the Oxford Center for Computational Neuroscience in England.
Differences in the sensitivity of those two areas are tied to chocolate craving, he said, and may play a role in obesity.
Gazzaniga-Moloo said it may be premature to tie weight gain to the newly identified fat-tasting genes, saying the studies don't yet show cause and effect.
Some people just prefer fatty foods
"If we do discover that people are fat-tasters, some more than others . . . this could explain why fat-free foods are not as popular as full-fat foods," she said. "It would certainly help us figure out a piece of the puzzle, why current fat replacers are not as performance-perfect as we thought they might be. I certainly think it's very interesting."
Keller said the information could be useful to help match people to diet plans that are better suited to their individual physiology. The food industry could also design more marketable fat-modified products based on the data, she added.
"In general, it's been difficult to create fat substitutes that are as palatable as the real thing," Keller said. "This could help in formulating food."
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