I think there are a lot of factors…my old guy had a good appetite to the end (if he liked the food!) He'd been put on the canned I/D after a pretty serious pancreatic bout and once his belly settled down he seemed always ravenous within a couple hours after eating. I called my vet and we added the I/D kibble and I finally worked out a ratio that seemed to keep him satisfied. His weight pretty much stayed consistent until near the end. He also enjoyed frozen snacks! Blueberries, frozen cut green beans (probably his favorite) and raspberries. He also liked fruits and veggies in general. I think nutrients are such a huge part of overall health for all of us. The better we eat the better we feel and live. I'd monitor his weight and go from there. If his weight is consistent and he's eating healthy food and treats you should be good
And a word to the wise. His bad bout of Pancreatitis (really bad) came after a big family cookout. Lots and lots of people and even though they were told not to feed him I am sure everyone thought to themselves oh he could have this one little bite of potato chip, or here Lou have this last bit of my hamburger or hotdog…repeat this scenario with just 1/4 of the people attending and your 7 lb dog gets well sick as a dog…I learned to sequester him in my bedroom during future parties. And did I occasionally feed my guy people food yes I did but very very limited. My big dog people friends forget that your Yorkie is a tenth or less of their dogs size but they break off or hand a little dog what they would hand their 80 lb. Golden Retriever.