I have a portly young cat and an elderly scrawny cat. One needs to gain weight, the other one I swear is like a Hoover vacuum cleaner. Feeding them two different foods is such a pain, nearly impossible. Feeding them on seperate floors, using jars so tubby doesn't hear the bag, waiting until one is asleep, turning on the sinkerater, locking one on the balcony...... blah,blah, list goes on forever! The baby, one and a half yrs. old, still sucks on my neck and arms, any skin, she just got diagnosed with a minor heart murmur and needs to lose weight, the other is elderly and needs too gain a couple lbs. The tubby kitty eats all the food of the older cat, it is infuriating!! I have had many cats and I really can't believe how much Lily eats, it's ridiculous. Mia probably got skinny because Lily chases her around, eats all her food and pisses her off. That said, we'll figure it out..... soon...I hope.