Make bone broth, take 3 chicken carcasses in a pot and fill with cold water until it goes over the bones then add vinegar (lemon juice can be substituted--the acid is needed to leach the calcium out of the bones), bring to a boil and then simmer for 6-48 hours, the more the better. The liquid will turn opaque and the broth will have a roast chicken smell to it. If you simmer it for long enough you can eat the bones as they will be very soft.

Here's an article on bone broth, how to make it, what's in it and the health benefits:
http://findarticles.com/p/articles/mi_m0ISW/is_259-260/ai_n10299306/?tag=content;col1

Doesn't Warren's link indicate that the acid is from ash, though? That, to me, says that meat is fine, but cooking is not.

"Ash" in this context means "stuff that isn't burned by the body".  My understanding is that there are some amino acids that can't be fully "burned" for fuel by the body and they are what promote acidosis.

Of course, if they are incorporated into muscle, they are still used by the body, even if not burned for fuel.  That may be why meat sometimes seems less acid forming than vegetable protein.