OK, so if we want to get technical... taste cells on the tongue contain chemoreceptors. Those turn chemical signals into potential - i.e nervous system signals

OK, so if we want to get technical... taste cells on the tongue contain chemoreceptors. Those turn chemical signals into potential - i.e nervous system signals. Since normal food has normal type chemicals, whereas manufactured, msg type food has make-it-taste-nice chemicals. Those are two different sets of chemicals and so, yes. food which tastes good is different from thinking it tastes good - they activate different chemical pathways and trigger different receptors.