Dulled Taste Linked to Obesity

People whose sense of taste is less acute than normal tend to choose sweeter foods that are higher in calories than those with normal ability to taste food. The diminished sense of taste can lead to obesity, say Cornell University food scientists.

"We found that the more people lost sensitivity to sweetness, the more sugar they wanted in their foods," said lead author Robin Dando.

Experts have suspected a link between dulled taste and obesity, but no tests had been conducted to see if losing taste changed the amount of food a person ate. In the new study, which was published in the journal Appetite, Dando temporarily dulled the taste buds of study participants and had them sample foods of varying sugar concentrations.

Researchers provided volunteers with an herbal tea with low, medium or high concentrations of a naturally occurring herb, Gymnema Sylvestre, which is known to temporarily block sweet receptors. During the testing, participants added sugar to the unsweetened tea until it achieved their desired level of sweetness.

Study participants added 8 to 12 percent sucrose to the tea. (Soft drinks are generally around 10 percent sugar.) Those who ingested the tea with the largest concentrations of the taste-blocking herb preferred higher concentrations of sugar.

"Others have suggested that the overweight may have a reduction in their perceived intensity of taste. So, if an overweight or obese person has a diminished sense of taste, our research shows that they may begin to seek out more intense stimuli to attain a satisfactory level of reward," explained Dando. This can influence their eating habits to compensate for a lowered sense of taste, he said.

The study showed that for a regular, sugary 16-ounce soft drink, a person with a 20 percent reduction in the ability to taste sweet would add an extra teaspoon of sugar to reach an optimal level of sweetness, as compared to someone with normal taste response.

The sense of taste may help experts understand the development of obesity, said Dando, and "taste dysfunction should be considered as a factor."

Another sense, the sense of smell, is also implicated in weight control, but the loss of smell had the opposite effect on weight. Researchers at the University of California, Berkeley, found that obese mice who lost their sense of smell also lost weight. But mice that retained their sense of smell ballooned to twice their normal weight by eating the same amount of fatty food as the mice with no sense of smell.

The study suggested that the odor of what we eat may play an important role in how the body deals with calories. If you can't smell your food, you may burn it rather than store it. But simply being able to smell your food may pack on the pounds.