[Photo by Zhang Tao/For China Daily]

A new phenomenon

Thirty years ago, overweight or obese young people were rarely seen in China, so weight-loss boot camps didn't exist. However, they have become common in recent years as a result of unhealthy diets and diminishing levels of exercise.

In 2015, there were 15.3 million obese children in China, the highest number in any country, according to a report published earlier this year in the New England Journal of Medicine.

Experts estimate that about one in four Chinese age 7 and older will be obese within 10 years.

According to the National Bureau of Statistics, there were 300 million people age 19 and younger in China last year.

In June, the Report on Childhood Obesity in China, compiled by a number of bodies, including Peking University's School of Public Health, predicted that without intervention the proportion of overweight or obese children ages 7 to 18 will hit 28 percent by 2030.

The report, based on data from nine mainland cities, said the proportion of overweight people within the age group had risen to 12.2 percent in 2014 from 2.1 percent in 1985, while the rate of obesity had soared to 7.3 percent from 0.5 percent.

"Obesity was neither an epidemic nor a public health problem in the 1980s, but now it's a growing and disturbing health crisis nationwide," said Mi Jie, director of the Epidemiology Research Center at the Capital Institute of Pediatrics in Beijing.

"Genetics, diet and exercise habits all play important roles in the accelerating incidence of obesity. With no radical changes in genetics, unbalanced nutrition, rich in fats and sugar, and a lack of physical activity are the main causes."

Last year, Hong gained 15 kg because of a lack of physical activity at school and a sedentary lifestyle at home. "I could lie on the bed for a whole weekend watching Japanese animations and reading comic books on my iPad," she said.

She often felt guilty about not exercising and forced herself to accept a strict diet of boiled eggs, vegetables and low-sugar fruits such as grapefruit and kiwis.

"But diets only lead to anorexia or overeating, both of which are bad for one's health. Unfortunately, I tend toward the latter," she said, reflecting on how the diet backfired and resulted in depression, anxiety and weight gain.

In common with many Chinese people, Hong's parents thought a chubby child was adorable and blessed. They didn't realize her weight was an issue until she started provoking pointless quarrels and began self-harming by cutting herself.