After asking for some more details about the research behind the National Child Measurement Programme (NCMP), I got back some research papers.
Here's the papers I got. Full-text availability is variable.
- Parents often do not recognize overweight in their child, regardless of their socio-demographic background (full text free)
- Telling Parents Their Child's Weight Status: Psychological Impact of a Weight-Screening Program (full text free)
- Recognition and management of childhood overweight and obesity by clinicians (full text requires subscription)
- Can we recognise obesity clinically? (full text requires subscription)
- Health consequences of obesity (full text requires subscription)
The second paper essentially describes the pilot study of the NCMP, and is an interesting read. One of the points made in the abstract, of course, is that "However, a minority of participants found it distressing, which highlights the importance of managing the process sensitively, particularly for families with overweight children.", and it's fairly clear from the news reports that the process has not been managed sensitively.
The first, third and fourth papers are all various ways of saying "Oh no! Not everyone is panicking enough about the obesity crisis! Even some doctors are relaxed!".
The fifth paper is the only one that attempts to show that "childhood obesity" is actually a problem - the other four proceed from the assumption that it is - and it's not a good paper (by which I mean it meets the internal standards of the field perfectly, but those standards are so bad that the paper is still terrible).
It shows a lot of correlation, but doesn't then go on to even consider the question of causation. The best example of this is probably the first area it looks at - psychological problems.
[...] We can conclude that obese children are more likely to experience psychological or psychiatric problems than non-obese children, that girls are at greater risk than boys, and that risk of psychological morbidity increases with age. Low self-esteem and behavioural problems were particularly commonly associated with obesity. [...]
Further on, in a section on long-term socio-economic effects of childhood weight:
[...] that obesity in adolescence/young adulthood has adverse effects on social and economic outcomes in young adulthood [...] For example, British girls born in 1958 who had BMI >90th centile when studied at age 16 had significantly lower income than girls with BMI <90th centile (by 7% on average) at age 23 [...]
Well, there's a surprise. It turns out that bullying and harassment, exacerbated in girls by the intersectionality with gender of appearance policing, and relentless social messages about the inferiority of fat people, will give fat people low self-esteem, with increasing likelihood as they get older and so live through and internalise more of this. When they get to adulthood, widespread discrimination in society then creates a noticeable pay gap.
Their solution is not to try to end this psychological assault but to reinforce it by blaming the victims for not being thin enough.
Given that they've entirely missed the obvious here, I'm not convinced that the claimed causation of other health conditions by "obesity" really holds either, especially since they admit that the evidence they review has weaknesses, and that the psychological impact is "likely to be the most widespread" consequence in childhood.
So, that's the quality of the evidence that the government is using. It's either terrible, or relies on assumptions for which the evidence is terrible. There doesn't seem a lot of point in writing back to point this out, though.