As far as I can see you can't go much further than fanatical Jainism if you don't want magic to be used.

If you will allow magic then you can go further because you can have druids. These guys can talk to animals and awaken plants. An awakened tree could probably donate wood to the elves.

The biggest issue I have with this idea is that it's going to be hard to explain WHY they're like this.
If they were created by a god this way then wouldn't the god have made them able to survive by eating rocks or absorbing sunlight or what have you? If they were created by a god and the god expected them to eat meat and vegies then why would they, as an entire race, decide to stop doing that?
If they were supposed to eat only fruit why didn't the god make a tree that produced a fruit that provided all their nutritional needs and also shed leather like bark and dropped iron like branches?
If you don't have interventionist gods, or any gods at all, how did their entire race end up with such odd social conventions and how have they not been wiped out by the orcs, humans, dwarves or whatever next door? Or indeed the wolves, lions or other top predator since they can't really produce any decent weapons they would probably get killed off by any large powerful predator in the area even ruling out big bad magical monsters.

You might have a reason for it all figured out but as a player, reader or casual observer if this wasn't handled well it would be a major problem for me to accept. Especially as you've already ruled out magic as a hand wave.