Selective pressure doesn't need to be perfectly foolproof to be valid. Humans are pretty observant, and have decent odds of noticing over time when particular

Selective pressure doesn't need to be perfectly foolproof to be valid. Humans are pretty observant, and have decent odds of noticing over time when particular things correlate with health problems. A plant known to cause health problems is less likely to become and remain a dietary staple. A plant that isn't a dietary staple misses out on a wealth of opportunity for propagation. I think you're also hyperfocusing on the issue of evolution. The point isn't that stevia is a plant which merely exists, but rather its longevity in human culture[0]. What you're saying makes sense for random plants picked up in the woods; less so for plants that have been consumed by humans since antiquity. By the same logic, there would be no a priori difference in risk profile between vegetables and random research chemicals. 0: https://www.britannica.com/plant/stevia-plant#ref350513 https://www.britannica.com/plant/stevia-plant#ref350513