Differential Effects of Diet and Weight on Taste Responses in Diet-Induced Obese Mice

Objective Previous studies have reported that individuals with obesity have reduced taste perception, but the relationship between obesity and taste is poorly understood. Earlier work has demonstrated that diet-induced obesity directly impairs taste. Currently, it is not clear whether these changes to taste are due to obesity or to the high-fat diet exposure. The goal of the current study was to determine whether diet or excess weight is responsible for the taste deficits induced by diet-induced obesity. Methods C57BL/6 mice were placed on either high-fat or standard chow in the presence or absence of captopril. Mice on captopril did not gain weight when exposed to a high-fat diet. Changes in the responses to different taste stimuli were evaluated using live cell imaging, brief-access licking, immunohistochemistry, and real-time polymerase chain reaction. Results Diet and weight gain each affected taste responses, but their effects varied by stimulus. Two key signaling proteins, alpha-gustducin and phospholipase C beta 2, were significantly reduced in the mice on the high-fat diet with and without weight gain, identifying a potential mechanism for the reduced taste responsiveness to some stimuli. Conclusions Our data indicate that, for some stimuli, diet alone can cause taste deficits, even without the onset of obesity.