system
Given the following post, respond as if you're commenting on Reddit:
human
Why are greasy foods considered tasty by many people?

Whenever I crave a greasy burger or pizza, I've always wondered exactly why this is?
gpt
Taste is basically the body's way of directing us toward the nutrients we need. Back in the dawn of our species, fats and salts were quite hard to come by.  Fat has the highest calorie density of any food, so our sense of taste makes it 'good', by eating it we increase the likelihood that we will survive, and thus pass on our genes. As the ability to pass on genes is the cornerstone of natural selection, there is a strong evolutionary pressure to value to taste of fat. 

As we lived in central Africa, in the beginning, salt was also hard to come by and is an essential nutrient.  So, by the same mechanism, we 'learned' to crave salt, as it encouraged us to seek it out.

Of course, now, the drive to eat salt and fat is no longer necessary and could arguably be said to be a draw-back, or a evolutionary weakness. But natural selection takes time to correct for mistakes and to adapt to new circumstances, so, you still love yourself some God-damn McFat.