A few tidbits that I can throw in:
Someone was trying to get naturism going in Thailand. I have no idea what has become of that.
The Japanese were free in concern of nudity before the American takeover of WWII. Then they politely changed customs to suit the American occupation, which now seems to have perverted the culture to this day. We have changed, but Japan is stuck in the 50's generally, but I could be wrong on that point, it's just what I see and read here and there. I remember in 1954 the baths were open to women, but going in with my dad with mom refraining. There were no women in the baths with us. This was only one location.
This is restaurant's rules are weird and I sense sicko, but it needs to be blamed on meddling ugly Americans back when.
India has those sadus and other sects, but that is regional and there are attempts to make it something to frown on. It is a male thing for the most part today. In South eastern India covering the shoulders and knees is respectful for women. Urination and defecation on the side of the road is common. Men work bare knee and shoulders. It all depends on so many cultural and social factors. Out and out nude is generally in the back country, which is remote and vast.
Jbee