Back in the 70s & 80s we attended gospel quartet concerts in Hershey, etc. We were impressed with the mennonite young folk with clear, acne-free complexions and attractive hair. Absence of junkfoods?
That’s probably a lot of it. But it depends on the mind, too.
It isn’t always true (there are some horror stories about growing up in very strict, traditional religious communities) but generally the Amish and Mennonites live pretty regulated, ordered lives.