> Can an exogenous molecule that was so adaptive be missed this bad and now consuming it will just fill that gap we had for millions of years?
I think the simplest answer to this is that for most of human evolutionary history, calories were scarce. And caffeine, like all stimulants, boosts metabolic rate both through thermogenesis and increased activity. That's a hard downside to overcome, even with a plethora of other health benefits.
For our hunter-gatherer ancestors, an endogenous chemical that burned an extra 100 calories a day could very likely mean the difference between life or death during a drought. That's not the case today, because calories are essentially free (in fact we're literally dying due to a surfeit of calories).
I can't believe I never thought of this. With this in mind, it seems that any drug is more likely to be a net positive iff it increases metabolic rate. I wonder if that is the case.
I think the simplest answer to this is that for most of human evolutionary history, calories were scarce. And caffeine, like all stimulants, boosts metabolic rate both through thermogenesis and increased activity. That's a hard downside to overcome, even with a plethora of other health benefits.
For our hunter-gatherer ancestors, an endogenous chemical that burned an extra 100 calories a day could very likely mean the difference between life or death during a drought. That's not the case today, because calories are essentially free (in fact we're literally dying due to a surfeit of calories).