No its not just a case of feeding him the meat. If you make up the diet yourself you need to learn what dogs need and how much, but there are many companies who now sell frozen raw diet, you just thaw and feed. Having said that, that’s the first time I have EVER heard of a lab being a fussy eater. I would advise a health check if you haven’t done this already it maybe that he has got some kind of stomach or digestion problem, or at his age, it might be a mouth/tooth issue making eating painful. Vet first I suggest!