This forum is about wrong numbers in science, politics and the media. It respects good science and good English.
My UK newspapers yesterday were full of a scare story about childhood obesity. This is a bete noire of mine, because it conflicts with my own observations. When I see my son's schoolmates, they all seem skinny and rather too tall for their age. And yet the Daily Mail is telling me 24% of schoolchildren are obese! That's obese, not merely overweight. Does the fact the I live in a middle england country area make a difference to what I see? Or is this an alarmist story, perhaps? In 1994 obesity rates were about 2%, it seems. I looked up the source, Colin Waine of the National Obesity Forum. Obviously this is a typical single-issue lobbyist outfit, with an agenda of social engineering and getting tax money, albeit there may be a problem with adult obesity for some people, there is an element of 'thousands will die' about it that seems to outweigh reality. I couldn't find the original quote or document, but I did find one thing that confused my statistics-blind brain. The standard for childhood obesity is based on BMI (much discredited I know) expressed as a percentile. Can this give a real figure?
May I ask does "middle England country area" mean Midlands? That seemed like a nice place when I was there. Do kinds in your neighborhood walk to school? To their friends houses? Ride bikes and goof off outside? If so, then there wont be a lot of fat ones. Urban kids who stay inside all the time because their parents are afraid of monsters don't get enough exercise, and there really are an awful lot of fat ones.
Surely the increase in the rotundity of children is simply ascribed to parents who are feeding them up in preparation for the advent of the bird flu pandemic which, surely, will kill more thin people that fat people. Won't it?
I fancy that the single issue whingers have totally missed the point that Nanny's message (about flu) somehow got through and people have used their judgement about how to best protect themselves.
The sad thing is that female fashion currently seems to highlight the (many) children and youths (of the female persuasion) who are more than a little padded but still insist in following fashion cues which would make stick thin super models look bloated.
The males are a different problem, mostly not too bad until they get into the beer drinking phase. But if they do get large they make excellent goalkeepers (goalminders perhaps for our off-shore readers ) mainly because, though immobile, they are quite capable of filling the entire open area through which a ball or puck would need to pass to register a score.
I think it all goes to explain why European cars have been getting bigger and, notably, wider in recent years. And could also be an explanation for why so many parents in London (for example) like to use large vehicles to get the kids to school. Well, that and the size of the potholes they need to traverse omn the journey.
There is a simple reason why kids are getting fatter - Its because the measurements we are using is basically wrong!
The BMI (Body Mass Index) is the system which is designed to tell us if we are too fat. It works on the idea that there is an ideal weight to height ratio, and if you go over it, you are fat!
The first problem with the BMI is that it only works for adults - kids are still growing and at times have parts of their bodies which are not in proportion (think big feet on 12 year old boys!)
The second problem is that the only proof that there is any ratio between health and BMI figures are not related to over weight but under weight. If an adult hits under 18.5 BMI, they are in serious trouble.
The issue of being obese has only been brought up recently when some health lobby decided to recommend that anyone over 27 BMI was obese, where for years before anyone up to 30 BMI was just consided overweight.
THe BMI figures tend to show that its only when people get up to the 35-40BMI levels that they start to have health problems.
Lastly, there is the issue of men v women and general fitness. The BMI was based on figures created by the British Army. They always took the height and weight of their reqruits and so had figures going bad many years. It was taken as gospel that a soilder is going to be as fit as a fiddle, and so the ideal weights were based on the average soilder.
Women are not built the same as men. Any fool can see that. Women are also prone to holding more body fat as a proportion of their weight. This means that a broad woman, muscular, and fit enough to lead an active outdoor life, could well be rated as being seriously obese - even though she could easily prove to be fitter than a man with a BMI of 23.
So, are kids getting fatter - only if you start looking for them near fast food places and using unreliable measurements.
"The second problem is that the only proof that there is any ratio between health and BMI figures are not related to over weight but under weight. If an adult hits under 18.5 BMI, they are in serious trouble. "
Well I'd take issue with this as well. I'm 35, have a BMI of around 17.5, and have for the last 20 years. No trouble there. A health advisor at the gym simply told me to eat more cakes.....
.... which raises an interesting issue. Having been to the Middle-East a fair bit for example, a lot of people there have a similar build to me (small-boned) and I'd imagine their BMIs often fall below the accepted threshold for the UK / USA / Europe. You can't have a globally universal standard for something like this. Pygmies anyone?
This is a very important point. The figure of 18.5 BMI is based on UK figures. The figures for people from other parts of the world will be different - but isn't that a good reason to completley dismiss the whole scare story if the figures used as a measurement are not reliable?!
Well, lots of people die of cancer. When they do, it's likely they will have cachexia, wasting away. If they are in the death figures, well of course a low BMI will look unsafe. Just because people have a low BMI when they die, it doesn't mean the BMI is the cause.
Ditto for the high BMI.
Back to the kids, I saw seven teenagers waiting for their school bus this morning. None of them looked obese, or even fat. Unless the new standard of obesity is not obvious to the casual viewer. By my calcs, the chances of no child in seven being obese, when the obesity rate is 24%, is about 15%. Maybe further research is needed.