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Sunday, February 17, 2013

The low-carb, high fat diet debate and deviant thinking

The low-carb high fat diet debate: Three videos, and thoughts on polarized views and 'deviant' thinking

One of the hot topics in exercise science and diet is the low-carb, high-fat diet concept, now backed vocally by Prof Tim Noakes in South Africa.  In December, he and Prof Jacques Roussouw debated the dietary guidelines with respect to cholesterol and its impact on heart disease, and a video of that debate can be found below.  The low-carb diet echoes other topical issues in exercise science, perhaps most notably barefoot running, in that it polarizes opinions between two opposing camps.  It then strays into 'rules' and over-simplifications, which are arguably incorrect.  Here's how to 'pole-spot' and embrace complexity, along with the low-carb debate

- Ross Tucker

In the course of a debate on doping and cycling a few years ago, a certain well-known exercise physiologist who had tested and defended Lance Armstrong publicly dismissed Jonathan and I as "newly-minted scientists".  True, of course, since we had both obtained our qualifications within four years of him writing those words.

He intended it as disrespectful at the time, suggesting ours was an opinion not worth listening to because we did not have 300 years of experience (and about as many conflicts of interests, I'd add) behind us.  I always viewed "newness" as a distinct advantage, because it brings with it some aspect of novelty, a new way of approaching an old problem.  That's often lacking in science and in many areas of life (coaches, managers, I'm looking at you!), and as I've evolved from newly minted to (recently?) minted, I've come to recognize that progress usually comes from forcing a novel view.  

Deviant thinking and innovation

I recently spoke to a group of financial consultants about the lessons I have learned about high performance teams from my involvement with sports teams and athletes, and one thing that I tried to re-inforce, in business and in sport, is that progress is the result of so-called deviant thinking.  By "deviant", I mean that person who pushes back against convention, who asks the apparently ridiculous questions and forces others to rethink their positions of comfort.  Deviants make us anxious, but they also drive innovation.

If we are allowed to drift along with the current, we never challenge paradigms.  Jonathan and I were both fortunate that our post-graduate training was overseen by Prof Tim Noakes, who is not newly minted but has retained the capacity to challenge current beliefs.  He is a scientific "deviant", in the most complimentary sense of the word.  In so doing, he has driven a change in perceptions around fluid intake and dehydration during exercise, and also has contributed to our understanding of fatigue and the role the brain plays in performance regulation.  These topics were, respectively, the subject of Jonathan and my PhDs, and so we have inherited this desire to push back against convention, hence the existence of, and many of the approaches and articles on, this website.

The low-carb high-fat diet debate

The latest area of Noakes' interest is diet.  Specifically, he is a vocal proponent against carbohydrates and processed food, arguing for a high fat, low carb diet.  In South Africa, it is impossible to give a presentation on exercise and health without some member of the public asking about Noakes' dietary views and their implications for exercise, weight loss and health.

However, it is not a topic whose specific content and details I am comfortable dealing with.  I am not an endocrinologist, nor a cardiologist, nor a dietician.  I understand the basics, but in the same way that my driver's license does not entitle me to tell Michael Schumacher, Sebastian Vettel or Jimmie Johnson how to drive, I would not presume to educate or correct the experts on diet and cardiology - I might ask them a few pointed questions, of course, and challenge their thinking, but there's a line that I wouldn't cross in terms of dictating to them.  I have not dealt with people struggling to lose weight, and have not encountered the very real, practical challenges they face.  I do not have a lifetime of expertise evaluating research studies on heart disease, though I can appreciate how many 'holes' exist in current thinking.  Nor have I devoted any length of time to evaluating the respective sides of this particular debate.

And so I won't delve into specifics, at least not now.  However, in order to make the debate as widely accessible as possible, which is important, I want to share with you three videos.  They are taken from the University of Cape Town's Centenary Debate, held last year in December, where Prof Tim Noakes and Prof Jacques Roussouw debated various aspects of the high fat diet.  The focus is very much on cholesterol and its links with heart disease.  The videos are long, but worth watching when you have the time.  I'd love your feedback, your thoughts on who "won" the debate and what it means for our understanding.  Those videos are at the bottom of this post.  

Thoughts on scientific concepts and complexity

But first, my view on this whole debate, without delving into the specifics.  My biggest "objection" as it were, is not to the content of the debate, but rather the manner and justification for each side's respective positions.  Below is part of a presentation I gave to the public last year, and in it, I mention two examples of how scientific progress and application to the public can be undermined by the natural, human desire to simplify the message and adopt a polarized view of what are actually very complex concepts.  (Click here if you are reading this in an email)

The first is the 10,000 hour concept for expert performance - a great theory, wonderful to motivate parents and young athletes about the value of training, but a pretty useless theory in practice - in sport, it hardly ever applies.  The second is barefoot running, which has been taken and transformed into a cure for everything without any evidence.  

Polarized science, rules and a wildly swinging pendulum

The result of these kinds of debates is a polarized science, one where the pendulum swings wildly from one extreme to the other.  We go from "Practice is the only thing" to "Genes are the only thing" and back.  Or from "Barefoot running will prevent all injuries" to "Barefoot running is a fast-track plan for physical therapists".  Neither is true as a "rule", though within any population, there will be those who succeed at the extremes, and those who fail.  That of course introduces a huge confirmation bias, because every success story is held up as "proof".  It also leads to cherry-picking, because anything not supporting the pole has to be ignored.  Those who advocate for those polarized positions must recognize that they are pulling everyone to the sides, where they may not belong. 

The same is true for diet and metabolism.  The reality is that we are dealing with complexity in physiology that can't be explained by one theory, and an obesity problem that does not have one solution.  Biological complexity dictates that what works for one will not work for another, and that's what coaches figure out very early with athletes, and dieticians learn empirically with clients.  The idea that shoes are bad is just as wrong as the idea that shoes are essential, because in any population, either could be true for some people.  These kinds of over-simplifications are damaging because they polarize understanding in a way that benefits few, introducing dogma that is then disseminated to the detriment of many.  And that is the point I make in the presentation above.

So, how is this relevant to diet?  Well, the same things I see from the barefoot debate appear to be happening in the dietary debate.  Conventional wisdom is challenged, and rapidly leads to the formation of two opposing camps, whose idealism is so at odds that the poor people in the middle, who are ultimately the "end users" of the information, are caught in a figurative stretching rack, being pulled in opposite directions by 'extremists'.  If it is difficult for experts to agree, then imagine how complex it becomes for those in the middle.

The problems at the poles

Science is never black and white.  It's one of the first lessons I learned, and have relearned weekly since.  Does dehydration impair performance and health? Is fatigue the result of chemicals in the muscle?  Is barefoot running safer?  Does cholesterol lead to heart disease?  There is no such thing as a straight-forward answer to any of these questions, and so a single extreme view is invariably wrong.  

It then becomes more about "how" the message is communicated, and not "what" is being said.  That is, the content of the deviant view almost always has value - the barefoot running concept, for example, may be incredibly helpful to many runners and I would strongly support that everyone take something from it.  On the other hand, there may be people who simply cannot succeed barefoot.   

What then tends to happen is that the polarized camps become almost obnoxious about their view, blaming everything but their view for the obvious failure to succeed 100% of the time.  If you are injured running barefoot, it's your fault, for instance, and its advocates seem to show no awareness that they are making exactly the same mistake as they accuse shoe companies of making before them.  It is that aspect of the debate that is most off-putting, and I find the same true in the carbohydrate debate.  The justification for a given position becomes more and more 'radical', and eventually, it is based on anecdotes, resembling a series of TV infomercials promising "more".  

Polarization also introduces a risk of weak scientific interpretation, and I've seen examples recently where an association study is dismissed as weak and unreliable when it suggests that carbs are important, only for the same type of association studies to be used as "proof" when they support the desired viewpoint a day later.

Ultimately, there is without doubt truth in any deviant view, but there is also a problem with the idea that the scientific pendulum should swing all the way from its current position to an entirely new one.  With respect to the carbohydrate debate, there is no question that Noakes has, like those advocating for it before him, contributed to many success stories and positive changes as a result of diet.  And by opening up the kind of debate you see below, he has potentially created enough "scientific anxiety" that it will stimulate a whole new area of research that will ultimately help advance our understanding of how INDIVIDUALS respond to different macro-nutrients, and hopefully reduce the obesity epidemic we face.

But in all this, and in debates about shoes vs barefoot running, and talent vs training, and methods of training and so on, don't feel compelled to pull the pendulum to the other extreme - remember, that's what you're suggesting others have done wrongly before!  There's no such thing as "we were 100% wrong before".  We just weren't 100% right, and it's the contribution of deviants who help us see that.  But stay away from the poles.

UCT Centenary Debate: the cholesterol debate

Right, so below is the debate.  It's one long video, divided into three chapters:
  1. Prof Tim Noakes introduces his theory (35:43)
  2. Prof Jacques Roussouw responds (43:21)
  3. Questions and discussion with the audience (51:05, but probably the most interesting aspect)
To compliment the video, you may also want to view the presentations (it's not filmed very well, have to say):

View Prof Noakes' presentation
View Prof Roussouw's presentation

Feel free to comment and share your views.  Again, I'm not going into specifics, it just isn't my place and feels disrespectful to people who arguably know more than I do about this, but gladly debate the manner of the debate and the way ideas are communicated!