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You’ve heard of a change in heart. How about a change in taste buds?
As if you needed more proof of obesity’s long-term negative impact on health, now comes a study from a team of food scientists at Cornell University. The researchers offer new clues as to why taste buds in people with obesity — defined by the U.S. Centers for Disease Control and Prevention as a body mass index of 30 or higher — typically diminish over time. Researchers have long observed the correlation between obesity and a blunting of taste, but the study, published this month in the journal PLOS Biology, offers new understanding of the actual molecular change that occurs to the tongue when it's fed a high-fat diet.
And here’s the good news: For all the times you’ve beaten yourself up over not losing weight, the study’s findings suggest the culprit isn’t so much a lack of willpower but the kinds of foods you consume and — far less obviously — the hidden role they play in dulling your palate. Researchers saw this indirect impact on taste buds when they fed mice a high-fat diet over eight weeks. By the trial period’s end, the rodents’ taste buds experienced an astonishing 25 percent reduction.
For the two of three Americans now deemed either overweight or obese by any number of medical organizations, the study holds big implications, researchers note.
“This research provides new clues about how humans might become obese and suggests a novel approach to combating obesity — looking at the taste bud itself,” said Robin Dando, an assistant professor of food science and the study's lead author. “If the same taste loss happens in obese humans, it’s plausible these people would be driven to eat more, or at least eat a more intensely tasting version of whatever they were eating.”
Inflammation as the culprit
The study’s mice proved that point. Divided into two groups, half the rodents were fed a high-fat diet composed of roughly 58 percent fat; the other half, a low-fat diet of just 14 percent fat. After the trial period, only the obese mice experienced diminished taste buds due to diet. The underlying culprit turned out to be inflammation.
Turns out, obesity doesn’t just make us, well, fat; it also makes us inflamed. Here’s how it happens.
The average human taste bud (nerve endings, essentially) consists of roughly 50 to 100 cells, each with an average life span of about 10 days. Collectively, an entire taste bud can take roughly a month to turn over and replenish. A high-fat diet disrupts this process of renewal. As researchers discovered with mice, fat triggers higher levels of a pro-inflammatory cell called TNF-alpha. The ensuing inflammatory response disrupts the “balancing mechanisms of taste bud maintenance and renewal," Dando explained.
“Taste dysfunction,” as the researchers note, is the end result.
For individuals struggling with weight loss, the study highlights a vicious cycle: A high-fat diet may not only see you pack on the pounds but also trigger the kind of inflammation that dulls your taste buds, making you compensate by eating more food.
Speaking with the Associated Press about the study, Stanford University bariatric surgeon John Morton, M.D., offered this advice: Eat mindfully. That means chewing roughly 30 times before swallowing.
Having tasty food also helps. That’s why recipes from culinary leaders like AARP Health Living chef Daniel Thomas can help; the acclaimed Washington, D.C., chef proves that low fat doesn’t have to mean reduced, bland taste. Try his recipe below.