I only have one Yorkie as you gals know, but my breeder has had many over her years of dog ownership and breeding. She has not shared with me any concerns over protein level in the food for Yorkies. She has made sure that I don't feed cheese. Just a wee tiney bit, and that is saved as a very very high value treat for Razzle.
For me generally speaking, high quality food is a must for any dog. But what is most concerning to me, at this point are the number of out of shape and obese dogs and cats around!. That presents a huge health risk for the animal, and it is so sad because at least the obesity is easily prevented. Feed amounts appropriate to age and activity levels!
Getting and keeping a dog in shape, should be relatively easy to. Walk your dog daily. You don't even need to power walk the pooch. If there is a hill or incline nearby, include this into your walk.
I met a woman the other day; she was in a wheelchair, and she had her Yorkie trotting beside her electric wheelchair! We chatted for a bit. That dog was in better shape than Razzle. Buns and legs of solid muscle. Nice deep chest; and not an ounce of fat on her! She takes her dog to leashfree parks, does obedience training with her; and if weather is inclement she plays with her dog at least three hours per day
Wowee She also has a personal assistant to help her wash and groom her gal.