Founders of Juice Joyce Hui Wei (left) and Jiang Taoxu.[Photo provided to China Daily]

We are in a bustling restaurant in downtown Beijing - or it could be any other Chinese city, town or village, for that matter. This evening the din of chatter mixed with soft music wafts through the warm summer's air, and the preoccupation of almost everyone seems to be matters oral: biting, chewing and swallowing the copious amounts of all kinds of food that has been delivered to their tables.

But in one corner of the restaurant sits a young woman who periodically sips juice from a small plastic bottle or dips into a small plastic container she has brought with her in a backpack, and which holds lettuce, carrots and a few other vegetables.

Welcome to a new world where those who have opted to starve their bodies of the better things in life for hours or days on end can happily sit right beside their friends and acquaintances as they gorge themselves on the very same better things in life.

Such scenes would once have been rare, arising only when a person, perhaps for medical reasons, had to eschew food dished up at restaurant tables.

Most of these suffering souls, adherents to the intermittent fast, are women, but whatever the gender, they have a similar agenda: to systematically ward of the temptations of fat, salt, sugar and calories that could compromise their fasts.

In that quest they have found help from a new industry, one that will obligingly provide them with the food - either solid or liquid - that will allow them to see their task through to its successful, healthy conclusion.