Switching from CAFO to pastured/grass-fed is the biggest for me. It's more expensive and living in a city with the social conscience of a gnat, pretty tough. More than half of my food is delivered from sources online.
It's not so much a religion, but a determination to not support and to not eat food that is produced by people who think that taking my money for shit food is called "business."
"Right is right, even if no one is doing it; wrong is wrong, even if everyone is doing it." - St. Augustine