We found my cat Gandolf Grey Beard just about one year ago. He was so skinny he could barely walk and was near dead. After visiting the vet we discovered that he was 10 years of age or older and his kidneys are failing. He does drink an accessive about of water (because of the kidney failure). He began to gain weight but now he is very skinny again. I can feel all of his bones in his back, ribs, and hips. He eats 1/2 a can of wet food in the morning and 1/2 can in the evening. I have tried giving him a full can at each feeding but he does not eat more than the 1/2. Gandolf does not seem to be in pain, he is still walking around and jumping but I am still concerned about his weight. People comment about how skinny he is when they see him. How can I fatten him up?