 We aim to identify neural factors that contribute to taste intensity perception in humans and to determine environmental mechanisms that contribute to variation in taste sensitivity. Significant controversy surrounds the possibility that consumption of artificial sweeteners AFS leads to weight gain. Given that the five FDA approved AFSs are found in thousands of foods Yang 2010 this marks a clear and significant gap in knowledge. Our preliminary data demonstrate a 3-fold decrease in sweet taste sensitivity following consumption of a beverage sweetened with two packets of Splenda for just 10 days. These data provide strong evidence that repeated exposure to sucralose reduces perception of sweet taste intensity, most likely by down-regulation of the sweet taste receptor. Therefore, it is imperative that we gain a greater understanding of the physiological consequences of AFS, since alterations in sweet taste perception, metabolism and brain reward that occur in response to AFS exposure may promote weight gain. 