[Pseudoscience-is-malarkey (OP)]

Obviously, not all food taste better with salt and/or fat in it, but these things...

[CliffordK]

My cats really don't like heavily seasoned foods, although their dry catfood is a unique blend of bland meaty flavors, but also containing many vitamins.

Most animals require a variety of minerals in their diet including sodium chloride (salt), as well as calories (oils and carbs).  Many animal species will find natural salt licks including hot springs to get minerals. 

Ancient humans must have discovered that the desire for minerals in the diet can be fulfilled with cooking with the minerals.  Salt is also a good preservative, and cooking can kill pathogens, aid in metabolism, and, of course, enhance flavors.

[wolfekeeper]

Salt is an essential mineral but not that common unless you're close to the sea. So we've evolved to taste and crave it, so that we seek it out.

Fat is high calorie, and often has vitamins dissolved in it, and some fatty acids are essential and cannot be made by our bodies, so we need to eat fat, and again, we can sense it, and tend to crave it. IRC we have tastebuds that can detect it.