As soon as food or drink is consumed

In this world people pee and poop almost instantly upon the ingestion of food or drink. It happens naturally. Though some energy is lost, so each person has to consume a greater quantity of sustainance in return.

Due to these circumstances, wearing clothes is optional and wearing as little as needed or nothing at all is much preferred. It presents an easier alternative to cleaning or removing articles of clothing each time food or drink needs to be consumed.

Some people have even mainstreamed the fad of cutout underwear for men and woman to facilitate the need to secrete their waste. But puritan naturalists have clamored for the idea of no clothes whatsoever, even shouting the slogan "Food in, Waste out, clothes off!".