I didnt quite get it when Edward detto to Bella in the fist movie.."It's not like drinking ur blood for instance"

If I understand te correctly Edward means that drinking animal blood is not the same o as good as drinking a human's blood, namely Bellas. He's comparing it to how it would be for humans eating tofu. It's Cibo and it sustains te but it's not the same as eating something else più appealing. So while Edward drinks animal blood he would much rather drink human blood especially Bellas.