Ban and tax our way out of obesity – top doctor
Could it be curtains for the buffet car? Banning snacks on public transport is just one way England’s departing chief medical officer, Dame Sally Davies, reckons the government could act to prevent childhood obesity. Others include tobacco-style plain packaging for junk food, a calorie cap for restaurant meals, adding VAT to products like cakes, and banning advertising of unhealthy food. If the measures sound extreme, so do the figures. The proportion of children deemed obese by their final year of primary school has quadrupled since 1990, with about a third of all year six pupils classed as overweight or obese. The health secretary says ministers will study the recommendations “closely”. But the railway trolley of drinks and light refreshments might be around for a while yet. Prime Minister Boris Johnson has previously expressed scepticism about measures such as so-called sin taxes.
I can’t remember the last time I saw an obese child in England. I’m sure I would have noticed. In my experience, children are almost never obese. Adults are quite often obese. Nobody used to bother about it.
But then, “deemed obese” isn’t quite the same as obese. Obsessive weight-watchers, in my experience, are people who look fine to me, but will insist that they’re “putting on too much weight.” And I guess if you’re a supermodel of some sort, you may notice the addition of even a single pound of weight.
Let’s suppose that some kids genuinely are obese. What business of the government is it to try to regulate people’s weight anyway? How is banning snacks on public transport going to bring their weight down? How long do English kids spend on trains and buses every day? It can’t be more than about half an hour. How many sandwiches can you eat in half an hour?
No, if there are obese kids, it’s more likely because they’re being well fed at home, or they’re being well fed at school. Banning snacks on public transport will probably have zero effect on child obesity.
And anyway I suspect that it’s imaginary obesity that is easily generated simply by changing what’s deemed obese. From the Orwellian Calorie Control Council:
BMI is a measure which takes into account a person’s weight and height to gauge total body fat in adults. Someone with a BMI of 26 to 27 is about 20 percent overweight, which is generally believed to carry moderate health risks. A BMI of 30 and higher is considered obese. … A BMI of 25 to 29.9 is considered overweight.
BMI less than 18.5 is considered underweight. All it needs is the stroke of a regulatory pen to change 30 to 25, and bingo, overnight you’ll quadruple the number of obese people. Wikipedia:
Body mass index (BMI) is a value derived from the mass (weight) and height of a person. The BMI is defined as the body mass divided by the square of the body height, and is universally expressed in units of kg/m2, resulting from mass in kilograms and height in metres.
What has the dimensions of mass per square metre? In my glaciation heat flow models I use density, which is mass per cubic metre, never mass per square metre, or even mass per metre. I suppose that things like carpets will have a mass per square metre. It’s called area density. I suppose cables and ropes will have a linear density or mass per metre.
What the hell is the square of body height? Why are we measuring people like carpets? Human bodies have a skin surface area of about 1.5 square metres, and given an average adult body weight of 70 kg, that means that they’ll have an area density – body mass per unit body area – of 70/1.5 or about 46.5. But given adult body height 0f 1.75 m, mass per square height is 70 / 1.75², or a BMI of nearly 23.
Body Mass Index, BMI, is a pretty meaningless number. It’s not even the same as area density, which would be a crazy way to measure people anyway. Two-year-old toddlers:
Average weight for a 24-month-old is 26.5 pounds for girls and 27.5 pounds for boys, according to the World Health Organization. How tall is the average 2-year-old? Average height for a 24-month-old is 33.5 inches for girls and 34.2 inches for boys.
27.5 pounds is 12.47 kg. And 34.2 inches is 0.87 m. BMI is 16.47
Typical weight of newborn babies is 2.5 to 4 kg, and height is 0.5 m, So babies generally have a BMI of 10 to 16.
So why aren’t babies and children regarded as underweight? Could it be that worried health-conscious parents have been feeding their underweight children to get their BMI up from 16 to 20? Well, no, while adults are compared to fixed values, children are compared with other children in their own age group. Which means that they’re compared to an ever-changing scale. Your obese child is overweight by comparison with other children in the same age group – which could mean that they’re all underweight.
The whole thing is crazy and meaningless. It’s crazy, meaningless non-science. BMI is a deeply meaningless number. It’s not even the same as area density
It’s the same of course with tobacco and alcohol and everything else. It’s all crazy, meaningless non-science. And it results in crazy, meaningless laws like smoking bans and buffet car bans.