Diarrhea? Cha, Cha, Cha...

Is normal for cats to, on occasion, have bouts of softer stools (soft enough to mark their fur a bit)?

I've been giving my cat baby food to determine if he has a food allergy to any particular meat protein. I suppose it's possible that the softness of the baby food could affect the softness of the stools, yes?

Thank you,

Jenk