Do not eat poisonous plants
And how exactly did the first humans centuries ago, happening upon a plant producing delicious-looking berries determine that it was poisonous? How do they make that determination without a life being lost?
What kind of sadistic God would make plants for food and invite man to eat of them all, then make some of them poisonous? Answer that.
Theists love to point to the beautiful things in the natural world as evidence of a loving creator. But there's also lots of ugly sadisitic things in the natural world too. Theists conveniently turn a blind eye to these.