I have a two and a half year old tabby cat, and he used to eat Friskies; seafood sensations. His weight ended up getting to 13.5lbs because he would eat just out of boredom. I cut the food intake down so he stopped gaining, and I slowly weened him off it and onto Blue Buffalo; Weight control formula. He's been on it for about a week or two now.. But for some reason he keeps gaining. I am down to feeding him about a cup a day and he's now up to 15lbs. Does anyone know why this might be happening?