A 167cm Girl Weighing 50.5kg Was Told She Was 'Overweight' — by a Children's Smartwatch
A girl of ordinary, healthy teenage size was flagged 'overweight, heavier than 99 percent of girls her age' by a Xiaotiancai phone-watch. Doctors say the watch mixed up its own data — and the episode reopened China's argument about whether consumer devices are teaching children they are fat.
She was 167 centimeters tall and 50.5 kilograms. By adult standards that gives a body mass index of about 18.1, a number medical authorities describe as slim — under the threshold for being considered low-weight, let alone overweight. But a child’s Xiaotiancai smartwatch looked at the girl’s height and weight and displayed a different verdict: “偏重” — overweight — with the added sting that she was “heavier than 99 percent of girls her age.”
The viral post recording that screen, republished by the Xiangsheng Morning News, opened with a parent’s fury. “You tell me what counts as normal,” she wrote. “Do you know how much anxiety this causes a teenage girl?”
The answer, from the company, only sharpened the puzzle. Xiaotiancai — China’s best-known maker of phone-watches for children — said the watch’s health app had generated its verdict from BMI using standards published by the National Health Commission. That was true, and also not the point: the commission’s own charts for adolescents of different ages and sexes do not put a 168-centimeter, 50.5-kilogram girl anywhere near “overweight.” The watch appeared to have taken a slim child and filed her under a percentile label that, taken literally, meant something a plain BMI calculation could not support.
The difference matters because the labeling is not a neutral feature. Xiaotiancai advertises exactly this kind of screen — height, weight, a percentile rank, a one-word verdict — to parents who buy the watch to keep track of a child. In China’s parenting culture, those numbers feed straight into the fierce, exam-scored competition over everything from English grades to piano levels to body shape. “This is not just body anxiety; it is weight anxiety,” one commenter put it, while another Weibo user read the image and replied with the reflex of a generation: “She’s skinny, what are you looking at?”
The child-health specialists pulled the same conclusion from the opposite direction. Tang Shuo, a doctor at Hunan Children’s Hospital, told the Morning News that adolescent overweight cannot be judged from BMI alone — you need age- and sex-adjusted reference tables, plus waist circumference, body-composition data and a physical exam. BMI of 18.1 for a teenage girl, he said, does not sit in the overweight band. A percentile label that simply ranks weight against peers, without those adjustments, can’t define “偏重.”
The episode caught fire because it compressed a much larger argument into one screen. For years, Chinese girls have pushed back against the idea, promoted across advertising and consumer tech, that thinness is the correct default for female bodies, and that a number on a device is an objective measure of moral worth. A smartwatch is supposed to be a health tool; here it looked like a machine for converting ordinary bodies into problems.
Technically, Xiaotiancai moved to dial down the conflict: after reporters asked, the company said it would send the case to a technical team for review. The question lingering on Weibo was whether a wrist-sized screen had any business handing a child a one-line judgment about her body at all.