The OP's question was answered quickly and there's very little more to be said about it.
A thread about eating disorders is likely to stray off topic into the wider context of health, food and especially overeating. Especially given the current epidemic of ill health in the developed world, which is strongly associated with over eating. JWI posting that 'nobody should comment on weight unless they're a doctor' is inevitably going to raise eyebrows.
Perhaps Winhill is baffled, as I am, at the seeming disparity between how solemnly people approach the topic of eating disorders, versus how seriously people view being overweight (not just obese). I find surprising the average person's lack of understanding of the risks associated with being overweight.
Webbo, the survey linked below suggests that a tiny
proportion of young people develop eating disorders. See below for population estimates. Yes these are likely to be under-reported and a great many people suffer in silence. But the numbers are still minuscule compared to prevalence of ill health caused by being over weight.
Threads like this make me question: if posts expressing concern about the tiny risk of a kid developing an eating disorder - because the poster overheard she may have been given an inappropriate message by a coach; then why not posts expressing concern because the other day a poster walked past a school and noticed 30-40% of the kids playing outside were overweight?
Those 30-40% of kids that are overweight, have become overweight with the tacit acknowledgment of parents and mentors. And those kids are looking at a worse future needlessly exposed to elevated risk of ill health and early death caused by excessive calorie balance. That's literally millions of young people in the UK.. Obesity and being overweight has insidiously become the normal yet a person's weight is something that - in JWI's opinion - 'you don't mention'.
Some stats to send all asleep, which highlight the prevalence of Eating Disorders and Overweight/Obesity:
Age-standardised rates of Eating Disorder were 37.2 (95% CI 36.6 to 37.9) per 100 000 in 2009. (Or 0.04% of population)
''The peak age of onset for an ED diagnosis in females was between 15 and 19 years. In this age range, the incidence of ED for females was 0.2% of the population in 2009.''https://bmjopen.bmj.com/content/3/5/e002646
1.6 million people in the UK are affected by an eating disorder
There are up to 18 new diagnoses of bulimia nervosa, per 100,000 people, per year
1 in 100 women aged between 15 and 30, are affected by anorexia nervosa (1%)
10% of people affected by an eating disorder suffer from anorexia nervosa
40% of people affected by an eating disorder suffer from bulimia nervosa
The rest of sufferers fall into the BED or OSFED categories of eating disordershttps://www.priorygroup.com/eating-disorders/eating-disorder-statistics
of 16 - 24 year-olds are overweight or obese in the UK.
Being overweight is the second leading cause of cancer.
Strong association with increased risk of diabetes, heart disease, stroke, depression.
''of the 4 million deaths (globally) attributed to being overweight in 2015, nearly 40% were not considered clinically obese''https://www.nhs.uk/news/obesity/being-overweight-not-just-obese-still-carries-serious-health-risks/
When JWI's says that nobody except a doctor should comment on somebody's weight I think that's completely wrong-minded. It prioritises not upsetting a tiny proportion of people who suffer a rare mental health condition, over talking openly and honestly about a well-known proven health risk for a massive majority of people at risk.
I think people should
have a greater awareness of the link between their personal choice of eating habit, their weight and their health, similar to how they would if they choose to smoke cigarettes. Especially young people. That increase in awareness won't happen by not mentioning weight.