You may recall a study that got plenty of coverage last January that suggested gaining some weight is not so bad for your health after all, at least in some circumstances.
After studying about three million cases, its authors found that for people who are older than 60, having a body-mass index (BMI) that ranks you as overweight may reduce your mortality risk. And while obese people had a greater mortality risk over all, those at the lowest level of obesity were not more likely to die during a given period than people of normal weight.
This was not the first time such a relationship between BMI and mortality was observed, but it was the largest study up to now that came to this conclusion.
As can be expected, critics raised some methodological problems with the study. But what seemed to particularly bother some of them was not the validity of the study, but that fact that its conclusions diluted the simple message they want us to hear: gaining weight is always bad, in any and all circumstances, and for everybody.
The prestigious science journal Nature recently devoted an editorial and a feature article to this controversy. What it shows is how far public health activists are willing to go to advance their agenda.
One of the most frequently quoted academic sources on nutrition in the media, Harvard's Walter Willett, thus declared that the study was "a pile of rubbish, and no one should waste their time reading it." He also described such studies as "dangerous," because, reports Nature, "they could confuse the public and doctors, and undermine public policies to curb rising obesity rates."
Foremost among the policies that may be threatened by this more nuanced discussion of the effects of gain weight are, of course, new taxes on fatty food and sweetened beverages, as proposed by various groups.
There is no evidence whatsoever that such taxes are going to reduce the level of obesity among the population. Obesity is a complex and multifaceted problem that cannot be tackled by crude measures to punish or restrict some behaviours.
But when a lot of money is involved in a public policy debate, you can be sure that some people will not hesitate to cut corners in order to promote their pet cause. And that seems to be the case not just for the economics of obesity, but also for the health statistics related to weight problems.
By the way, other media reported that this is the same Walter Willett whose own study presumably showing a link between aspartame and cancer had to be retracted at the last minute last year, because the statistical findings were too weak to support such a claim.
As Nature's editors wrote in their rebuke of Willett:
It is easy to see why those who spend their lives trying to promote the health of others gnash their teeth when they see complex findings whittled down to a sharp point and used to puncture their message. It is more difficult, from a scientific perspective, to agree that these findings should not be published and discussed openly, warts and all, purely because they blend uncertainty into a simple mantra.
Until not so long ago, Churchmen used to denounce scientists who came up with new theories and findings that threatened Church dogma.
It's unfortunate that nowadays, many activists believe they can reach their goals by ignoring or vilifying everything that doesn't fit into their impoverished view of reality.
Michel Kelly-Gagnon est président et directeur général de l'Institut économique de Montréal. Il signe ce texte à titre personnel.