I'm stupid and don't understand high pesticide with low pesticide. So those who eat a lot are good and those who eat a little are not? Also there is a sentence

I'm stupid and don't understand high pesticide with low pesticide. So those who eat a lot are good and those who eat a little are not? Also there is a sentence saying that people that don't smoke are more active have lower bmi have hypercholesterolemia. Is something off or I just can't read Sci studied anymore?