I brought in a mother cat and 4 kittens last August. After she was done nursing them, she weighed 12.5 lbs. By Dec when she was spayed she weighed 16 lbs. In April at the vet she weighed 22.2 lbs and was put on the Hill's Prescription Metabolic canned food. Her blood tests and thyroid tests were all normal. No signs of diabetes. I stopped free feeding (I have 12 cats total) I watch every calorie she takes in and don't let her have more than 300kcal/day. Today she still weighs 22 lbs and I'm very frustrated at no weight loss after 3 months of strict dieting. She is not active. What else can I do? Thanks in advance.