Here is my experience with Science Diet Light. My cat was on a STRICTLY rationed diet of the Science Diet Light for several years. Every time he went to the vet, he had gained weight! I don't know how it happened. But it did. I wouldn't go back to the Science Diet for that reason. Morgan developed diabetes and the vet put him on Purina DM, a prescription diet lower in carbs and higher in protein. He did well on that with the diabetes and also even lost about a pound. Recently I had to change his food for a month or so due to crystals in his urine. He refused to eat the DM after that. Now he is on the EVO and has been for about a year. He goes to the vet next month for a blood sugar test, even though the diabetic symptoms look fine right now on the EVO. I'll see what his weight is then also. Again I am very cautious about how much he eats. I hope you'll find a food that will work well for you and your kitty.