The recently announced decision of Birmingham City Council (BCC) to ban takeaways in close proximity to schools is an all-too-familiar example of how good intentions based on scientific illiteracy can lead to hopelessly flawed policy.
The flaw lies in the underlying, though unstated assumption, that frequent consumption of takeaways (and other “junk” foods) is driving childhood obesity rates in the West Midlands and that banning them will help to reduce these rates. This is an important claim; it is not merely that there is an association between eating “junk” food and obesity; it is that over-consumption of these foods causes obesity in children. It’s then a short hop to the conclusion that banning the sale of these foods would help to lower obesity rates in children. All of this seems blindingly obvious to most people. But is it true?
The available scientific evidence on this question is inconsistent and in general does not support an association between consumption of junk food and obesity in children. A recent and well conducted study from Norway showed that overweight children actually had healthier diets than their thinner classmates. Similar studies on consumption of sweets and fizzy drinks have failed to show any convincing association with obesity rates in children. These findings suggest that lack of physical activity may be a more important factor in childhood obesity than fast-food consumption, in which case banning takeaways isn’t going to help very much. Actually, it may make the problem worse because at least the children are walking to the takeaway!
As to whether banning the sale of these foods would make any difference, the short answer is that no one really knows. Even if takeaway consumption is an important contributor to obesity rates in children, it doesn’t follow that banning takeaways would lead to a reduction in obesity rates. The children may simply switch to eating other foods – cakes, chocolate, ice-cream, sweets etc – and get even fatter. Presumably BCC and other city councils across the UK would then have to consider banning newsagents, garages, corner shops and local supermarkets as well.
This whole argument about junk food is reminiscent of a similar claim made a few years ago concerning the role of TV advertising and childhood obesity. The Food Standards Agency (FSA), now thankfully defunct, was in the vanguard of the public hysteria about companies like Coca Cola and Cadbury who were vilified as immoral purveyors of “toxic” junk foods. Politicians, ever watchful for a suitably safe bandwagon to jump on, joined in by threatening legislation if these terrible companies failed to change their ways. Even Gary Lineker was attacked in the media because he had the temerity to suggest that a certain brand of crisps tasted good. Despite the frantic efforts of the FSA to find a clear association between TV advertising and obesity in children, no such association has ever been found. Unsurprisingly that argument has now all but disappeared, but it was based on the same kind of woolly thinking and scientific illiteracy as the current debate about takeaways.
So before the well intentioned, but misguided health promotion “experts” who came up with this idea are allowed to proceed with their experiment in social engineering as a tool for public health, it might be a good idea to pause for a moment to ask whether there is any reason to think it might work. There is, I’m afraid, little cause for optimism. No study has ever shown that the banning of fast-food outlets in close proximity to schools has had any beneficial health benefits for the children, because no study has ever been done. I assume this is because no one with the necessary expertise could be bothered addressing a question, the answer to which was already blindingly obvious (or at least obvious to anyone who could be bothered to think about it).
Still, if BCC is determined to pursue this ill-considered policy, here is my challenge. Get a detailed map of Birmingham showing the location of the main schools and takeaway outlets. Select those schools where there are lots of takeaways in close proximity and another group where there are none. Next, measure the heights and weights of all the children and see if those with local takeaways have higher rates of childhood obesity than those who do not. Of course, even if such an association were to found, it wouldn’t necessarily follow that takeaway foods caused the higher obesity rates, because there may be many other factors involved. But if there is no association at all between the frequency of local takeaways and obesity rates, then the question has effectively been answered in the negative. My own guess (and I’m willing to bet on it) is that no such association will be found and that, consequently, the strategy of banning takeaways would be an action based on faith, not reason. But like it or not, faith – however sincerely held - is not a sufficient basis for public health policy which may affect the lives of thousands of people. The only thing that matters is evidence.
As the old adage goes, “In God we trust, everyone else must bring data”.
Dr David Ashton
8th February 2011