Thanks everyone! I always start off really slow (1/4 of the newwith 3/4 of the old then after a few days goe to 2/3 old, 1/3 new etc.) but no matter what Tuffy's tummy always rebels. Giving some Diabac seems to help with the runs though. Never tried the white rice instead of the new food but that's something to consider. But,believe it or not, rice is one of the few things that tuffy doesn't like. He does like chicken flavored rice, though. Would that be an option?