Adding some digestive enzymes will also help. I have a JRT that tends to indulge,so she gets Digestive Enhancer to help digest all the extra that she sneaks. We've thought of keeping her in those clear plastic gerbil balls so she can't get her little paws into trouble!!!LOL!!!Just kidding really...
My old girl was on a homemade high quality low phosphourous protien diet at the end for her kidneys as well as Orijen 6 fish, I gave her Prozyme to help digest her food, it only made sense to me that as we age our digestive resources can get depleted for various reasons.
I keep a container of Digestive Enhancer from the Farmacy around all the time, never know when you'll need it.It has both probiotics and enzymes in it. It tastes good mixed with yogurt.