The idea

A friend of mine was a vegetarian when I met him, but he wanted to start hunting and decided that he would start eating meat that he either killed or caught, or that friends killed or caught. We’d go out and he would tell people he was a vegetarian, because he wouldn’t eat meat in restaurants or at people’s houses since he or they didn’t kill it or catch it. We used to tease him and say “you’re not a vegetarian; you eat more meat than we do.” So he came up with the phrase catchatarian