Most cats stop growing between 1 year and 1,5 years. Tigris has about the same weight he had at one year (am glad he didn't put up more ), Filou did not grow anymore after he was 1,5 years old. I would be careful with the kitten food.
As far as I know it is fatter than the normal cat food and most of our rotten spoiled Pet Talk kitties have rather a weight problem than the problem of starving whatever they tell you when you come home