I've been told it's the quality of the protein that matters, rather than the quantity. Unless you're feeding a low quality food with unnatural additives, etc I doubt it matters really. I haven't found any change in behaviour due to type of food - over time I've fed Sherlock Arden Grange, Fish 4 Dogs, NI, Wainwrights and raw and there's no noticeable difference in his energy levels.
Sherl's a working cocker with lots of FTCh in his family and is has very high excitement and energy levels - he just won't stop going until he drops. As an eg. a couple of weeks ago we took him to my in-laws' house after he'd had a very long walk, and he wouldn't stop running around the house until we took him home late in the evening - by then he was so tired that his eyes had rolled back in their sockets and I thought something had gone seriously wrong with him
We were going to take him to the vets when he fell asleep and we realised it was just extreme overtiredness. (Next time we go there I'll make sure he gets some time out on his own...)
I think it's just working cockers' natures to be high energy and diet isn't going to have much of an effect.