Weight loss induced by calorie restriction in mice is associated with a higher sweet taste response and increased fungiform papillae density

Diet-induced obesity resulting from excessive calorie consumption has been associated with taste disorders in both mice and humans. While this relationship is well-established, there is still limited knowledge on how calorie-restricted diets affect the sense of taste in normal-weight individuals. We hypothesized that differences in body composition of mice subjected to caloric restriction (CR) or intermittent fasting (IF) compared to ad libitum chow are associated with changes in bitter and sweet taste signaling. Male C57BL/6NRj mice were fed either ad libitum (control), 75 % of the weight of the ad libitum chow (CR), or were submitted to IF (cycles of 24 h fasting and 24 h refeeding) for two weeks. Gene expression analysis of taste bud cell types of the circumvallate papillae (CV) was performed using qPCR and microarray analysis, and the chemosensory surface of the fungiform papillae (FP) was analyzed at the tongue tip. Taste preferences for sweet (sucralose) and bitter (caffeine) were analyzed with a two-bottle preference test. The FP number was higher in fasting groups compared to controls by up to 35 % ± 9.8 % (p < 0.001) in the CR group, accompanied by increased Tas1r2 and Tas1r3 expression. Taste responses showed higher sensitivity and preference towards sweet taste in the CR group and reduced aversion towards bitter taste compared to control animals. In conclusion, this study demonstrates an association between body composition, FP, and changes in sweet taste sensitivity and preference in mice subjected to restrictive diets.