What kind of cat food is best to feed a medium sized dog?

I have a Basenji that weighs 15 pounds, hes is visibly underweight. He doesnt eat any type of dry dog food and the wet dog food gives him diarrhea. He seems to really enjoy cat food I have read that dogs are actually carnavores and that it would be ok to feed a dog cat food becuase he needs the protein and fat at this point. Any suggestions of a good brand? Thanks