My dog, however, is quite slim, tipping the scales at a mere 74 lbs. She was getting pretty porky at 85, though--and since she has a bad ankle, we put her on a diet. Long walks and measured portions of kibble helped slim her down.
*** My vet suggested it had something to do with the hormonal changes after being fixed.***
People were denying that for years, so I'm glad to hear a vet acknowledge it.
Maybe Tubby is eating Thin Cats food?