We have a 6 month old kitten who eats Whiskkas dry kitten food. The food is down all the time and she self regulates. The problem is I also have a 5 year old cat who has also always had free access to dry food and sself regulates. Neither is greedy and just eats what they need the problem is 5 year old cat has decided kitten food is tastier than normal food and due to the higher protein content is piling on the weight!!! Would it be Ok to feed them both normal adult cat food?