Is he eating Science Diet for medical reasons, or just because? If "just because", I have to suggest changing his kibble. Science Diet is...well, junk really. There may be a few applications where it's necessary (for medical reasons, such as our girl who has chronic pancreatitis), but outside of those few times, I wouldn't feed it to a dog.
A better quality food may help with both his digestive issues, and his desire to eat his kibble.