Children Asia are not immune to the global epidemic of obesity. About one in five Hong Kong schoolchildren are now classed as overweight or worse, according to the Hong Kong Department of Health’s latest survey, released last year. They were not eating enough fruit and vegetables, but eating too much salt and not getting enough exercise.

Experts everywhere have thought long and hard about how to keep kids slimmer, fitter and healthier.

Former US first lady Michelle Obama was committed to trying to get kids to eat more healthily and move more, play outside more and exercise more. In China, a handful of teachers and principals have won internet acclaim by instituting compulsory before or after school line dance sessions to get the students on the move.

Hong Kong kids are at a disadvantage because there are fewer neighbourhood parks and playgrounds for them to romp in. Encouraging exercise and sport is considered increasingly important in the global weight wars. Making kids diet, however, is probably not the answer.

The global weight loss company WW International (formerly known as Weight Watchers) last month released a dieting app for youngsters aged eight to 17.

Billed as a “scientifically proven behaviour change programme designed to help kids and teens reach a healthier weight, derived from Stanford University’s Paediatric Weight Control Programme”, the app has been met with a deluge of scorn and derision. Experts have slammed it as not “developmentally appropriate” and “deeply disturbing”.

The Kurbo app’s central idea is a traffic light system in which foods are labelled green (fruit and vegetables), yellow (lean protein, whole grains, dairy) or red (sugary drinks and desserts and other potentially fattening foods). Each child or teenager has a so-called weekly plan, and has to log the food eaten at breakfast, lunch and dinner, and the “activity” of the day.

WW added breathing exercises, a Snapchat-inspired interface, and a feature for children and parents to log their health-related goals. Weekly video coaching is available for a fee.

Some nutrition experts have said the Kurbo app and could promote “intense body dissatisfaction”. Before and after photos on the website fix the focus on weight loss, rather than on healthy eating and living, critics say.

Healthy but calorie-rich foods eaten by many children, including peanut butter, nuts, hummus and whole milk, get a red traffic light.

Originally developed by Joanna Strober when her son struggled with his weight, the app was bought by WW in 2018, and tweaked a little. Strober remains the CEO of Kurbo. Alexis Conason, a New York-based clinical psychologist who has written extensively about dieting, recently argued on the Psychology Today website that dieting “increases the risk of eating disorders exponentially”.

Kurbo, she noted, was a plan that ran counter to recommendations made by the American Academy of Paediatrics, which in 2016 warned parents and health care providers about the risks of focusing on weight loss and dieting with children and adolescents.

Meanwhile, a furious Change.org petition slamming Kurbo has been signed by 93,000 people, and is climbing.

“Tell Weight Watchers dieting isn’t for kids,” the petition reads. “The Kurbo app promotes habits that lead to disordered eating; employs ‘coaches’ with no expertise in health care; teaches children to attach their value to their weight; preys on parents’ fears in its marketing; has been condemned by the National Eating Disorders Association; and has been rejected by hundreds of nutritionists and dietitians.”

Pulling no punches, the petition dubs the WW decision to launch the Kurbo app as “dangerous, irresponsible and immoral”.

“It is time for you [WW] to put human lives over profit. You must pull this app and save thousands of children from developing and supporting life altering eating disorders that will eventually kill some of them.”

Twitter has resonated with varying opinions of Kurbo. “Such a great idea,” writes user Nancy Veluvolu. “Puts simple help in the hands of parents and kids to learn what great choices are green light be wary of yellow light not much of red light! Love it.”

Other Twitter users were not so enthusiastic. Benjamin Kinga writes: “Kurbo can be a great app for promoting healthier eating habits and better relationship with food – but they did not consider the unintended consequences. Restrictions/negative food relationships can easily create terrible long-term eating disorders among impressionable kids.”

So far Kurbo is only available in the US, Canada and Singapore, where it has secured a government contract, but it seems likely the for-profit WW organisation has plans for its introduction elsewhere. “We are thrilled to introduce Kurbo in Singapore as part of our international expansion strategy to provide a convenient option for busy parents and children to improve health outcomes,” Kurbo CEO Strober said.

“Together we hope to spread the word that there is an effective and sustainable solution to help the entire family eat better, and feel better.”

Kurbo nailed down the Singapore contract after two successful pilots in Singapore schools in which seven out of 10 students who completed the 12-week programme successfully lost weight. The company is reportedly working with Singapore’s Health Promotion Board to provide Kurbo to children between the ages of five and 17 with an age-indexed body mass index in the 90th percentile or higher.

Like many other places, including Hong Kong, Singapore has seen a disturbing rise in obesity over the past 10 years – as much as 60 per cent – because of the growing popularity of fast food rich in fat and carbohydrates and an increasingly sedentary lifestyle.

Steph Ng, a Hongkonger who now lives in the US and has studied eating disorders extensively, is adamantly opposed to the notion of children dieting.

Current research, she says, has found that 97 per cent of people who diet gain the weight back within three years of the diet beginning. Weight fluctuations from the repeated see-saw of diet, weight gain, diet, weight gain, can have terrible health effects, she believes.

“From my personal struggle with an eating disorder in my early teenage years, I’d also like to argue that the risks of encouraging children and adolescents to diet far outweigh the benefits,” she says. “Social influences and the media played a large role in the development of my illness, and I have no doubt that the constant reminders to restrict certain foods from an app would be even more damaging.”

Obesity, she adds, is not the core problem; in other words, it’s not the weight specifically, but unhealthy behaviour.

“I am sure many people would agree that the thinnest person they know is probably not the healthiest person they know,” she says.

Ng would prefer efforts to promote better childhood and adolescent health in Hong Kong and China to take a different tack, and avoid pushing dieting entirely.

She would like healthy food choices to be more broadly available to Hong Kong children, with balanced meals in schools, the widespread provision of organic fruit and vegetables, and the common use of enjoyable school exercise, possibly including group movement classes.

“Importantly, all of these initiatives should focus on promoting health for people of every body shape and size, rather than on encouraging weight loss,” she says. “Weight loss/change is not the key to health. Weight change may occur as a result of changing health behaviours, but it is not a prerequisite for health.”