Two customers of Juice Joyce with the juice.[Photo provided to China Daily]

In February, Jiang Taoxu of Shanghai quit from a well-paid job in finance to set up with two partners an online company, Juice Joyce, that produces bottled cold-pressed juice.

The company began selling its products in June and says it already has 3,500 registered users, and handled more than 800 orders.

Jiang says his confidence in his company's products is born of personal experience.

When he was in finance he traveled frequently and ate irregularly, which exacted a heavy toll on his health, making him putting on weight and becoming weak, he says.

In early 2013 he started intermittent fasting at weekends. He began to shed kilos, and about six months later he felt he had much more energy, a better appetite and was generally more healthy.

Late last year he decided to take the plunge and get into the juice industry, realizing that with few cold-pressed juice products on the market he needed to act while the iron was hot.

Jiang saw the demand as a simple one: many of those on intermittent fasts have little or no time to prepare the appropriate kind of food themselves, and there are people who want to "cleanse" their body or simple enjoy the taste of fresh juice.

Cold-pressed juice can help rid the body of toxins and provide good nutrition that is low in calories because the juice is exposed to minimum heat and air, he says.

Reliable figures on the size of the juice market in China are hard to come by, but about 20 companies sell cold-pressed juice in the country, most in big cities, Jiang says.