I'm not, of course, suggesting that activities such as exercising and eating balanced meals aren't important.  I highly encourage everybody reading this to take part in fun activities and eat your fruits and vegetables.

The problem is that the current focus on lifestyle factors vastly overstates both the negative effects of lifestyle factors, as well as the positive outcomes that can be expected if more people were to adhere to lifestyle advice.

Dr. Ben Goldacre, author of the book Bad Science, summarized the issue quite well in a talk he gave (which is available from his website):

Research into nutrition and health has come in leaps and bounds. There's been a huge amount of material, and there's a huge amount of material to play with, and there's a huge amount of material to obfuscate around in interesting and new ways. And more than that, there's also an interesting historical, political, and social context.... Tobacco: Public health epidemiologists enormously buoyed by this extraordinary discovery that tobacco causes 95 to 98 percent of lung cancers. ... At the same time, the patterns of disease were changing, because, of course, golden age(of medicine), better treatments, and also improved public health in terms of clean water and so on. People were living longer and people were dying of diseases of old age which sort of felt like they must be lifestyle diseases. And mainstream medicine made promises that it couldn't deliver on. Richard Dole writes in the introduction to a very famous tract on epidemiology in the early eighties confidently asserting that either a third or two thirds of all cancers will turn out to have dietary or other lifestyle causes. We haven't been able to pay out on these promises. That's not what the evidence has ultimately shown. We've found shavings of changes in risk, usually in observational studies. Whenever we've tried intervention studies on diet... If you look at the evidence in total, actually, it turns out that we weren't really able to pay out on the very specific promises that we were making thirty years ago. ...The only real genuine evidence, best thing you can say for most of the population (in terms of nutrition and health) is "eat lots of fresh fruit and veg."

Back in 2004, the CDC in America released an estimate that overweight and obesity was killing 400,000 people a year.  This was big news, it meant that excess weight was the #2 cause of death in the US.

But then cracks began showing in the foundation of this claim.  First, it was pointed out that they made a calculation error which had inflated the figure by about 35,000 deaths.  This was pointed out fairly quickly, but the CDC took a few months before it finally got around to admitting it's mistake and making a correction.

Second, it soon became clear that the study was based on extremely poor methodology.  The CDC still stood behind the results for a while.  But when the Journal of the American Medical Association in 2005 published the newest numbers, derived from much improved methodology, the new estimated number of deaths was 25,814.  A tiny fraction of the original 400,000.

The CDC no longer stands behind it's previous claims.  But they say a lie can spread halfway around the world while the truth is tying it's shoelaces.  I still hear doctors and health experts on television quoting the 400,000 figure in attempt to alarm people into changing their ways.

So what we have here is a lot of people who believe that if we could get more people to live healthy lifestyles, we could possibly save up to 400,000 lives.  This leads to incredibly unreasonable expectations as to what we might be able to accomplish if we just get the social engineering aspects right.

The same kinds of unreasonable expectations can be seen in many of the other statistics quoted in this vein.  For example,  you often hear doctors and health experts say that if we could just get people to live healthier lifestyles, we could eliminate about 80% of heart disease.

This figure is based on a study in the New England Journal of Medicine, and the figure severely misrepresents what this study can tell us.

I won't get into all of the details here, but the main problem with using this study to make such claims is that the study participants did not represent the segment of the population that make up the majority of heart patients.

The study participants were women between the ages of 30 and 55.  Heart disease only affects a tiny minority of the people in this demographic.  In fact, the difference between the incidences of coronary events between the highest risk and lowest risk groups was about 1 in 125.

Age is the single greatest risk factor for heart disease.  The vast majority of heart disease incidents and death occurs in senior citizens.  It's the #1 killer of people over 65, and decreases rapidly in prominence as you look at younger age groups.

This isn't to say that you can't make lifestyle choices that will help strengthen your heart so that it lasts a little longer.  It's just that in the end, your heart is your hardest working muscle, and if you manage to dodge all the other bullets that could take your life, it's going to be the organ that finally gives out on you just due to wear and tear.

People are living into doddering old age with a greater frequency than ever before.  This is the reason why heart disease is the #1 killer in the US.  When people who are supposed to be medical experts encourage the expectation that we can eliminate 80% of heart disease if we could just get people to fall in line, they're doing the public an incredible disservice.

People get the impression on hearing figures like these that we have the power to slash the death and illness rate.  This makes it an empowering message, and it accounts for why many people accept it wholeheartedly.  But the story just can't work out as it's sold.  It's a recipe for continual disappointment, and never ending "wake-up-calls" for taking action.

I don't think anybody can deny that there has been an increase in average weight throughout the 80's and 90's.  The problem is that calling this increase an "epidemic" is pure hyperbole.  Most people don't realize that the difference in absolute risk for diseases associated with excess weight is usually in the single digits percentage wise.  Often, as is the case with related forms of cancer, the difference is less than 1%.  Most people are incredibly surprised to hear this, but it's all by the official numbers.  These are the "shavings of changes in risk" that Dr. Goldacre was talking about.

Does this mean that you should feel comfortable eating chocolate cake without limit?  Of course not!  We just shouldn't put more of an emphasis on changing people's lifestyle than is warranted by the evidence.  We're actively misleading people about the way medicine and the human body work. 

And I believe that's helping to push people into the arms of alternative medicine, so that they can get their quack remedies to flush out toxins and melt their fat away.

And it leads to all sorts of silliness by researchers as well, from a study suggesting that all Americans will be overweight by 2048, to a study saying that a single high fat meal can negatively impact your health.  Back in February I looked at a claim that children were becoming increasingly too fat for their car seats.

And I think that people just have a gut reaction to these kind of claims in a way that it feels like this has to be correct.  I used to have arguments online with people who believed I was wrong on this.  I've mostly stopped getting involved in those discussions because it feels like I just have the same argument over and over again.

But I'm still surprised by the force that this kind of gut reaction exerts.  Recently in an online discussion I mentioned that it's a myth that sugar causes diabetes.  That this is a myth is the accepted consensus, and not disputed.  So I was surprised to be challenged on it at length.

So I expect that some of you who've made it this far in my long, rambling article are going to think that I'm a crank on this one.  Well, it's my policy to always admit that I could be wrong, and if I am, it won't be the first time.  If I got anything factually incorrect or made gross errors in my interpretations, I would love to be enlightened.

This is an issue with a hell of a lot of aspects to it, and I've done quite a bit of research on it.  Way too much to go into all at once here.  But I hope I've managed to get across the reasons why I feel so concerned about the state of the public discussion regarding our health and lifestyles. 

If I've come across semi-coherently at all, perhaps I've at least given some of you something to think about.