Fasnacht is one I haven't heard of before, but it makes sense, with so much German/Dutch history up there in Pennsylvania. Fat Tuesday is the literal translation of Mardi Gras, and comes from the old tradition of using up all the "good" food (the fats, butter, sugar, etc) before the Lenten Fasts began (but before you feel too bad for those monks, remember they lived on "liquid bread"--beer-- for the whole lent season...) Pancakes were a convenient way of using up the last of those ingredients, or so the story goes...
My favorite tradition is the pancake races in England... *SO* wish this would catch on in the US!!!
https://metro.co.uk/2019/03/05/pancake-day-races-london-happening-times-8820924/
But for the topic... I do think it's a combination of both genetics and lifestyle... My husband loves coffee, creamer, red meat, and smoked for years. He hates all seafood--gags at the smell, let alone the taste-- and most vegetables... he'll eat lettuce with a ton of dressing, bell peppers, raw carrots and celery, green beans, potatoes, and peas (fresh/frozen.) Oh, and corn. He'll only drink milk if there's chocolate in it... you get the idea... His bloodwork is perfect, no cavities, nada. He's adopted, so I don't know if it runs in his family, but at any rate, he got lucky. His one really good habit is that he drinks a lot of water, though that only started in the last few years. Being Texan, he'll also guzzle sweet tea by the bucket if it's available...
Meanwhile, I have to work at it, always have, and when I don't, it shows. Even when I'm being really "good," my blood sugar sits naturally right at the cutoff line... but my family has a long history of horrendous health, so I've always known that it was coming. I feel lucky that after all I put my body through, it hasn't revolted on my worse than it has.
