I think it's a hit or miss, really. I'd say to try it, see how it goes, and go from there. Try the formula with the least amount of protein. I currently am feeding my girls the formula with the MOST amount of protein which I thoroughly have regretted, as it gave Violet AWFUL diarrhea. She is currently eating it with pumpkin mixed in, with no ill effects, and we're going to hopefully try it w/out pumpkin pretty soon here to see how it goes. As soon as the bag is gone, we'll be changing her to something with lower protein (probably TOTW, but I'm not sure - I've been advised for AND against it, so I'm torn right now).