Well that's what a recent PepsiCo study sort of set out to explore. Briefly, researchers randomized a small group of matched individuals to consume either a low-sugar, artificial sweetener free diet (40% reduction in simple sugars and total ban on artificial sweeteners), or a regular one for 3 months time after which they were told to consume whatever they wanted for the final month of the study. Participants tracked food by way of food diary, and given the nature of the experiment, clearly they weren't blinded to their study condition, and nor were the researchers. Each month of the study, participants were asked to rate the perceived sweetness of vanilla puddings and raspberry flavoured sweet drinks.
By month three the sugar and sweetener reduced folks were rating the pudding as 40% sweeter than the control diet group. They did not however rate it as any less (or more) delicious. There was also no change in their weight compared with the normal diet folks.
This was a small study, but that said, its findings aren't particularly heartening. If foods perceived as sweeter by those who have reduced their sugar intake are not also perceived as less enjoyable, the swap to a low-sugar diet won't be self-reinforcing and hence will be more prone to failing in the long term, and the fact that weight didn't change speaks to the notion that simply removing sugar from your diet isn't likely to be the weight-loss panacea some bill it to be. If only it were that simple.