Agree as always with Gab, let me add to it.
Yes, over stimulation! Steady, consistent, daily activity is best for them not only b/c it burns off that energy, but they can count on it, and as importantly it establishes you firmly as the pack leader. I'll cut AJ some slack late at night when he gives me the evil eye, but if he bit or lunged at me and certainly if he got protective of food and toys, I'd intervene to re establish my authority. You need to do the same. She needs to earn more of the stuff she get now for free.
Start by working on the "Ok!" command, that's giving her permission (And by extension, you taking and exerting control) to do *Everything*: So, when you put the food down, when you walk out the door, when you open the car door, when she comes up on the sofa, ..so she learns to associate the word "OK!" with permission If she ignores you, firmly tell her to wait, hold the food back for a moment or two, and then put it down and say "OK".
A Vizsla will suck the life out of you if you let them and feel absolutely no guilt, and along the way, they'll realize they're also in complete control..who can resist that face? You can. You need to gently and consistently re establish your authority. And if she's growling and looks like she's going to bite, back off.