March 21 (UPI) -- Researchers have figured out why obese people seek higher-calorie foods: Inflammation from added weight may be killing taste buds.
Cornell University food scientists based their conclusion after examining the tongues of fat and normal-weight mice, publishing their findings Tuesday in PLoS Biology.
The researchers found that when mice became obese because of a high-fat diet, they lost nearly 25 percent of their tongue's taste buds.
"This is a potential human mechanism for getting fat," senior author Robin Dando, an assistant professor of food science at Cornell, said in a press release. "Evidence suggests that obesity from an unhealthy diet results in a powerful [metabolic] inflammatory response. In mice, this response disrupts the balance of taste bud renewal, reducing how many mature taste buds these mice have."
The mice studied by Dando quickly gained weight.
"I can say the mice are happy. They love this unhealthy diet, and pretty fast they get pretty overweight," Dando said to NPR.
The researchers tested normal and obesity-resistant mice. On a high-fat diet, the normal mice gained about 30 percent of their base body weight on a high-fat diet.
Eight weeks later, their tongues were dissected and analyzed.
Obesity has been studied from numerous perspectives, but the taste buds weren't examined.
"Despite evidence that taste is weakened in obesity, and rescued with weight loss intervention, few studies have investigated the molecular effects of obesity on the taste system," researchers wrote in the study. "Despite this, various groups studying functional responses from taste buds of obese rodents have noted an altered response to sweet and fat stimuli, often accompanied by a decreased behavioral response."
Taste buds, which consists of about 100 cells, can detect whether food is bitter, salty, sweet, sour or umami.
But when the normal level of 10,000 human buds is reduced, they seek out stronger, more calorie-laden foods. This includes food with more sugar and fat.
"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," Dando said.
As a consequence, the scientists see a new strategy for weight loss, writing "research provides new clues about how humans might become obese and suggests a novel approach to combating obesity -- looking at the taste bud itself."