Predominantly environmentalism. Buying vegetables over meat is just radically lower impact. I buy local (or, better, grow it myself) as much as I can can too.

Ethics certainly is a concern, as is health. Though, I have a lot of allergies, which makes it challenging at times. Still, I’m used to not being able to eat a lot of food, to restaurants not having anything I can eat. So I already was cooking most if my food from scratch, so it wasn’t the hardest pivot, even if my diet is objectively quite restricted