Were humans originally vegetarian?

The prooftext of original human vegetarianism is Gen 1:29. And it's possible that the traditional interpretation is correct. However:

i) The language is permissive rather than contrastive. It doesn't say they were granted vegetation as opposed to meat. Although the verse allowed for that distinction, it's not a logical implication of the verse. The verse isn't worded in terms of two antithetical sources of food, where one is verboten. 

ii) Explicitly stating that vegetation is generally permissible to eat might be theologically relevant insofar as it foreshadows the significance of two particular trees in Gen 2, one of which is forbidden. 

iii) Gen 1:24-26 includes a category of livestock. Normally, certain kinds of livestock are consumed. Indeed, that's one reason to domesticate them. It's easier than hunting. 

But even if we don't press that issue, some livestock are also used as a food supplement for milk and eggs. But even on that "vegetarian" interpretation, the intended scope of Gen 1:29 can't be confined to an exclusively plant-based diet (fruits, nuts, roots). Rather, it presumptively includes supplementary food provided by farm animals, even if, for the sake of argument, we don't insist that they were butchered for meat. But that means the licit original diet of man was already wider than Gen 1:29. 

The only alternative is to suppose the livestock were used as beasts of burden, rather than a food source of any kind. But that's highly artificial, and unlikely that the original audience would draw that dichotomy. 

iv) In addition, the tree of life wasn't give for food, but it was permissible to eat. So a food stuff isn't the only function of plants, in the creation account. 

v) Humans often prefer herbivores to carnivores for meat. (That depends in part on what's available for consumption.) So there's an indirect link between a meat diet for humans and a vegetarian diet for livestock and game animals. A vegetarian diet is foundational to a meat diet. 

vi) Another way of putting this is that Gen 1:29 is permissive rather than prohibitive. Although the wording is consistent with a ban on meat-eating, that's not entailed by the wording.

Moreover, given repeated references to livestock in the same account, it's implausible that a human diet consisting only of vegetation was originally allowed. The narrator couldn't reasonably expect the original audience to have such a restrictive view of what livestock is for. 

Even if, for the sake of argument, we think Gen 1:29 excludes the consumption of livestock, how could it also be understood to exclude the consumption of milk and eggs from livestock? 

What's the point of livestock? Other than a source of food, the only other function is beasts of burden, but God created Eden with an orchard, It already had fruit trees. So there was no pressing need farm the land with oxen. 

Of course, humans domesticated wolves for guarding and hunting, but that's not terribly consonant with the vegetarian interpretation. 

Mind you, the reference to livestock might seem anachronistic in a creation account. Did God directly create livestock? Are they not, by definition, domesticated wild animals?

So the reference might be proleptic. But even so, livestock are represented as part of the original goodness of creation, and not a natural evil due to the fall.