My Mickey is the same...she likes to eat often but doesn't gain any weight. She was so chubby at one time and now weighs half of her heaviest weight. Our older kitties are a blessing, it is our duty to give them all the comfort we can in these twilight years! Yeah Moritz...snuggle in and enjoy!
Moritz is doing well, always eating with a good appetite but although he is eating for two he loses weight, 100g every 2-3 months. Blood test results are okay so I'm afraid the black spot in his pancreas the vet could see in the last ultrasonic testing is something malignant.