I'm glad to hear Vita doesn't have kidney problems. With older cats that can be a reason of weight loss too. But of course her little teeth gave her problems to swallow. Filou had 7 lbs when he was healthy and is now down to 6,5. He (on top of his kidneys) has tooth problems as well and he doesn't eat then.
So with a kitty over ten we have to watch them all the time They are so good in hiding their ailments.