This study will examine the effects of sugar and sweeteners on the brains reward system by measuring brain activity while you taste sweet flavour. Currently sugar is regarded as a non-volatile taste stimulus and therefore sensed by taste and not olfactory receptors. However, in pilot scans examining the effects of a nose-clip on vs a nose-clip off condition it was found that brain activations to sugar were much lower and were in different brain regions with the nose-clip on vs the nose-clip off condition. Given previous studies find that mice can use odour cues to discriminate dilute sucrose solutions from water (Zukerman et al., 2009) this pilot suggests non-taste effects might be playing a role in the brains response to sugar. Therefore, it would be of interest to know if sugar vs sweetener activates the brain differently with nose clip on vs off and how a modifier might impact this. Proposed Work: This study will examine the effects of sugar and sweetener on subjective taste (pleasantness and mouth fullness) and neural reward responses in the human brain in healthy adults. We will have both nose clip on and nose clip off conditions. Closing the nostrils greatly reduces or eliminates air-flow through the nasal cavity, thereby reducing concentrations of volatiles reaching the nose from the mouth. The aim is to block air-flow through the nose using nose-clips, to eliminate retronasal olfaction.