In our sedentary lifestyle with our fat and sugar rich diets we really are fish out of water. Our preferential tastes for fats and sugars evolved in natural environments in which they were relatively scarce. There are few fat hunter-gatherers. Their active lifestyle keeps them fit. Babies have an innate, evolutionary developed and natural preference for sweet tastes.
Breast milk is sweet.
A liking for sour and spicy tastes is acquired. Adults have about 10,000 taste buds which are divided into the four groups of sweet, sour, salty, and bitter. In comparison, rabbits have 17,000, parrots 400, and cows 25,000. We taste sweet things on the taste buds at the tip of the tongue while sour things are experienced at the sides. Bitter things are tasted at the back of the mouth as if intended to give a last warning just before it disappears down the hatch and while there is still time to gag.