And I accept that you may be happy with your faith in the tenets of the public health folk. To explain, we'll start with this from the Director of Public Health in Sheffield, GregFell:
"The fundamental point is that obesity is a complex systems problem, and the location of fast food outlets can’t be causally disaggregated from all the other factors."This is a statement of faith, in a belief that the reasons for the increase in obesity from, say, 1980 to 2000 was a consequence of something called an "obesogenic environment" rather than by, for example, changes in human behaviour consequential on increased wealth and improved technology.
The public health position - as captured by Fell in another blog posting can be summarised:
"spot on – stop asking ‘does it work?’ and instead ask ‘how does it contribute?’”The premise here is that the 'system' is too complicated for us to understand it - we must act on faith rather than evidence in deciding what is the right thing to do. And individual elements of the system can't be seen as in any way discrete because to do this denies the interconnectedness that is central to the public health faith.
"Complex systems adapt in response to interventions so we shouldn’t necessarily expect changes to distal outcomes."
So we persist with ineffective smoking cessation interventions because it is the "right thing to do" and because such interventions "contribute" (and in doing so ignore successful market-based development of effective substitutes). We continue "Tier One" activities despite the almost complete absence of evidence of their effectiveness because using the "wrong evidence paradigm might lead us to do the wrong thing". Now forgive me if I don't fully understand what Fell means by an "evidence paradigm" - the term is used to distinguish between RCT (randomised control trials) evidence and the process of trial and error as well as a welcome shift from the old model of medical imperialism where the doctors diagnosis and conclusion was all the patient received to a model where the evidence on which those decisions are based being shared with the patient. None of this is about doing something you think is "right" despite there being no evidence to support this belief (or worse, as Chris Snowdon observes, actual evidence to say that it doesn't work).
The pragmatic evidence about public health leads us to reject the main thrust of this faith's adherents:
The evidence on smoking cessation tells us that reductions in smoking rates are consequential on three things - public education, price and substitutes. Advertising bans, cessation programmes, bans in public places, standardised packaging - all the rigmarole of modern anti-smoking - simply aren't making a difference
Alcohol consumption is for 90% of drinkers almost entirely benign (and arguably health positive) so reducing the whole population's consumption does not reduce harm. Again public education, price and substitutes matter more that warnings, packaging, advertising restrictions and intrusive licensing
The rise in obesity is not a consequence of that "obesogenic environment" (or, if you prefer, "complex system") but rather the result of reduced levels of every day physical activity resulting from the largely beneficial introduction of new technologies (there's a clue in the term 'labour-saving device'). Average calorie intake has fallen while average weight (and weight/height ratio) has risen - this change is not the result of a social shift from cooking and eating our own food to getting someone else to do the cooking for us
You are, of course, welcome to disagree with what I say here but I'm confident there is evidence supporting my position. This means that, if I'm to change my view, you need to produce evidence that falsifies my argument that much of what we're doing in public health is purposeless fussbucketry based on blind faith in the view that public health problems (drinking, smoking, burgers) are caused by problems in the social environment. And therefore that any intervention in that social environment must 'contribute' to reducing its negative impact even if we can find no evidence to support this belief.
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1 comment:
From the perspective of a biologist such as myself, there actually is such a thing as an "obesogenic environment", but that environment is rather simpler than you might imagine.
The single largest item on the energy budget of any person (indeed any mammal or bird) is the energy needed to maintain a constant body temperature. Therefore anything which changes the amount of energy needed to keep warm is going to have a fairly big effect on the energy budget of a person.
In the last thirty years or so, two big changes have happened to the energy budgets of people: central heating and duvets.
When I was growing up forty-odd years ago, I lived in a semi-detached house where the only heating was two gas fires downstairs, and I slept in a bed mostly insulated with blankets. I was living in a much colder environment, and sleeping in a less amply-insulated bed in a much cooler bedroom.
In those dim and distant days, before the advent of modern synthetic fabrics, clothing was also less insulating. People expended more energy keeping warm, hence weren't able to gain fat weight quite so easily.
The changes needed to reverse this trend have already been set into law; it is now illegal not to fit thermostatic radiator valves to bedroom radiators. If people did as I do, and limited bedroom temperatures, they would be slightly lighter.
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