Returning to eating meat safely?

[Meg]

I am planning on beginning to eat some meat (mostly lean
proteins - chicken, fish, etc) after being a lacto-ovo
vegetarian for over 10 years. Does anyone have any advice on
how to slowly begin incorporating these items back into my
diet without making me sick or shocking my system? I have
had trouble trying to find anything on the internet
regarding this issue.

Thanks.