A woman practising bigu.[Photo provided to China Daily]

There are also low-calorie foods such as salads and semi-cooked meals to keep intermittent fasters satisfied, he says.

In Beijing, Nuan10.com, a one-year-old online meal provider, began selling low-calorie meal packets in April, and says such meals have now become its most important product category.

"We came up with the idea of producing appetizing low-calorie meals when we saw that for some people it is difficult to rely on juice or salad when they are on a fasting diet, says He Miao, a marketing executive with the company.

"And of course we realized that intermittent fasting has become very popular, too."

The meals contain meat, vegetables and fruit, and their calorie content is carefully calculated, he says.

Since May the company has sold more than 600 two-day packages, which cost about 200 yuan.

One niche group among intermittent fasters in China is those who practice bigu, a fasting technique associated with achieving immortality in Daoism.

Zi Xia, of Beijing, says her company has provided bigu training to both Chinese and foreigners for three years and was one of the first to do so.