Matt,
Natural Balance limited ingredient foods are lower in protein, and with the very limited ingredients they work out well for determining food issues and giving the GI tract time to settle down. If it does solve her symptoms, then after 3 or 4 months, I would try slowly adding another brand of grain free food with higher protein and more ingredients to see how she reacts. If at all possible, you do not want to be locked into just one brand of food. All of the brands, including Natural Balance, are apt to change or discontinue formulas without notice, and you need to have other foods to feed when this happens.
Also, when you start transitioning to the Natural Balance, do it very slowly over at least a two week period. Natural Balance does not add probiotics to their food and it will take longer to do food transitions with it.
