About a year ago, on the recommendation of a conservative friend, I began cutting back on their dry food and started them on Wellness brand can food. Both my cats love it! It's high quality, high protein, low carbs. But it ain't cheap. About $1.70 for a 5.5 oz can. My skinny cat is maintaining his weight, while my fat cat has loss about 1.5 pounds. (He now weighs about 19 pounds)
It pisses me off that vets push that Science Diet crap and I’ve told them that. Dogs and cats do not need grains and that was the source of the deaths in pet foods.
Here is an excellent site to see reviews with detailed analysis of ingredients.
http://www.dogfoodanalysis.com/dog_food_reviews/