The act of eating is a service.

[Diana]

Sitting on the edge of the wharf casting a bobber out into the water in hopes of catching tonight's dinner, the fisherman sets down the rod to chase after a new distraction.

He grabs his dipnet and chases off into the bushes after a young porcupine, where upon catching up to it he begins to bludgeon the little creature into a bloody pulp of unliving flesh.

After his little adventure he returns to his fishing pole which now has a nice tasty trout securely hooked on the line. He reels it in and removes the fish from the hook and clubs it over the snout with a stick to stop it from squirming around.

Satisfied that he has dinner for the table he strolls over to a nearby bush and relieves himself there, thereby killing the plant that has finally succumbed to regular toxic shock.

I don't think we really need to establish boundaries here. Do we?

Even worse than the above scenario, is an advanced, educated society buying neat little packages of food from the grocery store effectively cutting off the knowledge of where the food came from. Very ingenious of humans.