Its shown in Breaking Dawn as well as in "the short second life of bree tanner" the nature of how appealing and un-appealing human and animal blood is. Specifically During Bella's first Hunt. Animal blood is explain in detail
It shows why a majority of vampires do not adhire to a deit of animal blood. Seeing this if you were turned would you adhire to strict diet of Animal blood? and you simply caint say "yes" as not many have the restraint nor the tolerance for it. such a thing. And especially not you..
i dislike it when other's say "i would be a like the cullens", beacse their the good guys" or the good vampires.
The cullens have restraint and even more tolerante, to live life with a diet that is eqavalent to "tofu".
If i turned i would not adhire to their diet, lest my mate would then only then i would think i could or attemp to. until then i would continue a normal diet one (human blood)