I've cared for several breeds in the past, and I LOVE Royal Canin. It comes in formulas that are breed, age, or activity specific. I have a Yorkie male that was always thin looking. All the vets said he's just meant to be skinny, that's his metabolism. I couldn't stand feeling his ribs. He ate well and tested healthy. I TRIED EVERYTHING! I got Royal Canin Yorkie flavor, and now he's PERFECT, ABSOLUTELY perfect in weight, and has a very pretty coat and bright eyes. I LOVE this dog food. Also, my female was always on the chubby side...She is now just a teeny bit heavy, if at all, more like solid, I would say. They BOTH look great now. Available ONLY at vets, pet stores or online, and it is pricey, but I think it's worth it.