I don't know the answer about meat and reflux, but I do know that it can be difficult for some babies to digest and some just find it icky. Formula and/or breastmilk should provide him with all the protein he needs, so you might hold off on meat for a bit longer if it isn't agreeing with him. There are plenty of healthy babies who never ate meat (mine didn't until he was 2), and there are other great sources of non-meat protein out there. Yogurt, cheese, cottage cheese, milk (when your LO is older), and tofu, just to name a few.