**Avoiding animal products which may not meet criteria of your religion.** Some people's religions allow the eating of meat or other animal products, but have restrictions on it. (As opposed to lifetimes' [answer][1] about religions that prohibit meat or animal products outright)

A workmate at a previous job eats vegetarian/vegan when she goes to restaurants because the meat (possibly dairy) may not be kosher.

[Appeal over baby-killing butcher's $3000 compensation][2] mentions a Queensland prisoner who chose vegetarian food because he was (incorrectly) told that halal food was not available.

I thought I heard about some case involving prisoners choosing vegetarian/vegan because they were offered food described as halal but were not confident the food was really halal, but all I can find is a mention of Guantanamo Bay's food being [mainly vegetarian][3].


  [1]: https://vegetarianism.stackexchange.com/a/75/531
  [2]: http://www.brisbanetimes.com.au/queensland/appeal-over-babykilling-butchers-3000-compensation-20130815-2ryb7.html
  [3]: https://www.defense.gov/Photos/Photo-Gallery/igphoto/2001087871