A good point. A "pot au feu", for example, one of those traditional French dishes with meat and lots of veggies, used to be cooked on Sundays in the countryside. A temptative comment would be: "ah because it took a long time to cook?" (ps: takes over 3 hours), but the most probable answer is because meat was something you wouldn't eat very often, which you'd, for example, keep for church day.

Hey, maybe I'm on to something here. It would be interesting to note how religion and meat have been entangled in the past. And I'm not thinking about the Cathars, Buddhists, or even Japanese edo-era edicts banning meat, but about bans on meat in some parts of Europe during the Middle-Ages. I think there were some, who knows anything about this? Maybe some catholic ruler of France did this for some time, I have a faint recollection of something along those lines.