system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 How come junk food taste better than healthy food ?
gpt
It contains lots of fat, sugar and salt.

For most of human history, we didn't have access to a lot of those, so our evolution made it top priority to get them (by making them delicious). Now we have an abundance of them, and our evolution hasn't caught up yet.