Inclination towards sweet-tasting foods may be decreased with the help of gastric bypass surgery according to a study by researchers of Penn State College of Medicine. The study was funded by The National Institute of Diabetes and Digestive and Kidney Diseases and the National Institute of General Medical Sciences. The experiment conducted on rats may help in initiating better treatments for the morbidly obese.

"Roux-en-Y gastric bypass surgery is the most common effective treatment for morbid obesity," said Andras Hajnal, M.D., Ph.D., associate professor, Department of Neural and Behavioral Science and Surgery. "Many patients report altered taste preferences after having the procedure."

A small sized gastric pouch is created in this surgery which bypasses a part of the upper small intestine. This method results in significant weight loss which differentiates it from other weight-loss programs. It also helps in fighting medical conditions inclusive of stroke and diabetes related to obesity. The surgery conducted on the rats altered the gastrointestinal anatomy resulting in a shift in the perception of the taste in the brain. These rats displayed a diminished inclination for sucrose rich water. Their response to sour, salty, and bitter substances remained the same even after the surgery.

"It appears that an uncontrolled appetite may get further boost from altered taste functions during development of obesity and diabetes," Hajnal said. "How much of this vicious circle is due to changes in the neurons inside the brain, which receive taste sensations from the tongue and report to the higher order motivational brain centers, we don't know."

The movement of 170 neurons found in the brain, which are responsive to taste was recorded by the researchers. The study revealed a change in the firing activity displayed by the neurons which was found to be akin to the behavioral reaction that was measured in lick rates within a ten-second time period of the rats.

"This supports the applicability of this rat model of Roux-en-Y gastric bypass to humans and also suggests that the observed taste changes following the surgery were not related to 'human factors' such as awareness and compliance to dietary and behavioral interventions," Hajnal said.

"These findings confirm obesity-related alterations in taste functions and demonstrate the ability of gastric bypass surgery to alleviate these modifications," Hajnal said. "We do not suggest, however, that the findings reported in this paper are the only neural consequences of gastric bypass surgery related to altered postsurgical food preferences.

Nevertheless, understanding the underlying mechanisms by which gastric bypass surgery affects taste may help in identifying therapeutic targets that mimic the beneficial effects of the surgery on appetite control and food choices, without the risks and complications of an invasive surgical procedure."