Across China: The A4 waist -- the China's latest absurd online fad?

What is a perfect body? In the eyes of some misguided Chinese women, it is characterized by a tiny midriff that can be fully covered by a vertical sheet of A4 paper, and they are taking action to get one.

"A4 waist challenge" has been trending on China's social networks since mid-March, when celebs posted "photos" of their waists completely hidden behind a 21-cm sheet of paper, and perhaps behind liberal doses of photoshop which can conceal so much more.

On SinaWeibo, the hashtag #A4Waist# has garnered more than 120 million hits and 34,000 photos have been posted. Some people are even taking it seriously!

Hu Zi, 18, is on a three-week fitness course via a mobile app, saying she was stimulated by the skinny waist craze.

"Not only an 'A4 waist', I also want a little pointed chin," said the vain young woman, who is 1.65 m tall and weighs 55 kg. She claims her ideal weight is 45 kg. She is also displeased by her "stubby" legs. "I haven't worn any trousers or skirts with hemlines above the calf for seven years."

Some gyms have rushed to provide services for clients like Hu, handing out leaflets with pictures of fitness instructors holding A4 sheets.

In Shijiazhuang City, capital of north China's Hebei Province, the Qingmu Fitness Center offers a course promising an "A4 waist" that has drawn crowds of young females.

"For the first time, an anaerobic exercise class is more popular than an aerobic class," said the course instructor, who acknowledges that the concept of "A4 waist" is nothing but a stunt.

"Bodies are different. The pursuit of a uniform physique is not healthy," he said.

Criticism of a series of online contests to show off slender figures in China has been rife, and they are blamed for reinforcing Chinese women's obsession with skinny bodies.

The "A4 waist challenge" comes hot on the heels of the "belly button challenge", in which one attempts to touch his or her belly button by reaching behind one's back.

"Why stick to one single standard of beauty? Especially when the standard makes ordinary people feel bad about themselves?" said Tian Susu, a communications researcher with the provincial academy of social sciences in Hebei.

Guo Qing, deputy head of Hebei General Hospital, describes those who want to meet the A4 standard as "ridiculous," because waistlines are determined by many factors, including the width of the pelvic bone and rib cage, not just body fat.

Guo is worried by the effects of these "challenges" on the health of young girls, many of whom resort to excessive dieting and diet pills, rather than a fitness regime.

His worry is not alarmist. A pop song "A4 Waist" circulating on Weibo, says, "I want an A4 waist. I eat very little every day...fruits are my diet pills." Endit