Why Did We Evolve a Taste for Sweetness?

The question seems to imply that since these things are supposedly bad for you why would your body want them at all. Of course sweet things aren't completely bad for you, in moderation they are good. Sugar is part of breast milk and part of an important stage of human development. Sodium is the same thing, it's good to have some of it and too much is bad for you. So it seems to me the question itself is flawed, it comes from the perspective of a 21st century human who may be concerned about dietary health from an "after the fact" POV.

I'm one of those human beings who finds sour and savoury foods more palatable than sweet things, if I'm honest.

I like sweet things, don't get me wrong, but I prefer bitter chocolates, black coffee, and so on... I always find people with a "hyper-sensitivity" to sweet things interestingly peculiar... I'm by no means a sugar decrier in an IIFYM sense, but I've seen both my elder sister and one of my best friends consume sugary foods until it has literally rotted their teeth away. I find it fascinating because I got incredibly fat on next to no sweets whatsoever.

It's more a question of how our minds perceive taste, and ultimately how it can benefit us to control that perception... and I think it's transitional across all of the gustatory perceptions.

One of the most interesting parts of nutritional psychology - to me - is how certain foods trigger pleasure receptors in certain people and how reliant we can become on foods as a sort-of antidepressant. (I don't believe it's an addiction by any stretch of the imagination, but I do believe that the gratification we derive from eating is linked to problems we have with improper behavioural eating.)