Tuesday, September 06, 2011

Will there ever be a grand unified theory of obesity?

In the nutrition blogosphere there's a bit of a debate going on right now. It started during a recent conference on ancestral health when Why We Get Fat's Gary Taubes criticized the theories of researcher and blogger Stephan Guyenet, and while criticism is all fine and dandy, it was the manner in which Taubes addressed Guyenet that led Guyenet to launch his own critical analysis of Taubes' work.

In a nutshell, Gary Taubes is the champion of the carbohydrate hypothesis of obesity, and Stephan Guyenet, the food reward hypothesis.

So who's right?



Both and neither?

Does it matter?

While I'm not fond of the way Taubes tends to argue in terms of what appears to me to be his liberal use of logical fallacy, personal observation, straw men, and ad hominem, I do think highly processed carbohydrates are involved in societal weight gain.

I also think there's a great deal of merit to Guyenet's belief that the hyperpalatable foodstuff that makes up the bulk of our modern food environment short circuits the brain's normal ability to moderate intake (you can read Guyenet's series on food reward on his blog starting back in April of 2011).

As a clinician however, neither strike me as the one right solution. Most people simply aren't going to be willing to restrict carbohydrates to the point of a natural reduction in caloric intake, nor do I think people are going to be willing to live on bland diets forever.

That said, reducing carbohydrate intake (especially ultra-processed carbohydrates) and trying to minimize exposure to hyperpalatable foods, are in fact both recommendations I regularly provide my patients.

So why isn't there one right way to go?

Probably because people are complicated. Both psychologically and physiologically. Brains are pretty crazy places, and so are chromosomes in that there are literally 100s of genes involved in eating behaviours, metabolism, appetite, etc.

So does anyone truly believe obesity has only one cause and therefore only one solution?

In Guyenet's case, the answer's clearly "no" as he's said as much,

"The food reward/palatability hypothesis of obesity is not mine, it's a hypothesis that originated in the 1970s, perhaps earlier, and is a major subject of ongoing obesity research. I don't expect it to explain every instance of obesity."
In Taubes case, it would appear as if his answer's "yes". Carbs or bust. In fact his most recent blog post recounts how he believes that for decades, presumably unlike he himself, pretty much all researchers have been operating with, "suboptimal intelligence" and that their "wrong answers", "border on inexcusable".

It's quite the righteous stance given the very clear holes Guyenet (and others) are able to poke in Taubes' theories.

Of course I'm confident Taubes will find some real holes in Guyenet's theories as well - something he plans on doing on his blog over the course of the next little while.

That's because unlike physics, I don't think anyone (other than potentially Taubes) really believes that there's one grand unifying theory of obesity, so there will always be holes to find in every theory.

The Daily Lipid's Chris Masterjohn covered this "Dietary Dogmatism" well, and I just want to weigh in and comment that pigeon holes are small.

Carbs, food rewards, mindfulness, whatever - it doesn't really matter. Bottom line being that if you figure out what works for you, stick with it regardless of whose theories resonate with you intellectually, because unless their application helps you to find a means to manage your weight living a life you actually enjoy, you'll have to keep on looking.

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  1. Forget Guyenet and Taubes, I found Peter Dobromylskyj's response to Guyenet the most fascinating of all. :-)


    If nothing else, the debate prodded Peter to write his post. Perhaps none of these bright lights has the story right, but it sure is fascinating to read the discussion.

  2. Interesting post! I also do not believe that there is one unified theory of obesity. I liked Seidell's explanation of why science has not come that far in understanding the obesity problem and finding solutions (also not in defining the overall grand theory). He states that overweight is a 'wicked problem'. I discussed his arguments in a recent blog post:

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  4. I'm just a dumb ass who has figured out the "secret" to living a healthy lifestyle. I have absolutely no higher education credentials in this area ... and that's a good thing.

    Yoni, you and everyone else make the assumption that eating foods with health benefits are bland ... they are not. This provides the uninformed who might want to change an easy out ... "If I eat foods that are good for my health and weight, it will be boring". That is a false statement/assumption.

    No doubt, the issue is complex. However, my specialty is simplifying things.

    While Michael Pollan has whittled it down to seven words, I have trimmed it down to two.

    As I tell my audiences, if you can master these two words, you will never look back.

    1. Satiety
    2. Taste/Flavor

    That's it folks. The rest is just highfalutin hooey.

    Gotta go: I'm boarding a plane to give a speech about this tonight (Health is Your Greatest Wealth).

    Ken Leebow

    P.S. Online, there's a tremendous amount of amazing resources that provide insight from very well-informed experts. And, thank you Yoni for keeping me abreast of diet and health issues. Keep up the good work.

  5. It's your assumptions Ken that are flawed.

    I'm not suggesting healthy foods are bland.

    Stephan Guyenet is however suggesting purposely consuming bland food is a means with which to combat obesity.

    Considering how long you've been reading my blog, I'm rather put off with your comment.

  6. By the way, here's a great quote from Steve Jobs. I begin all my presentations with it.

    Instead of bickering over the details, let's apply his thought process to the diet, health, and lifestyle world ...

    There’s no company in the world that’s better at making complex technology simple. That’s Apple’s primary skill and it’s a skill that’s never been more valuable.
    – Steve Jobs

    Source: BusinessWeek 2004

  7. I find your comment "As a clinician however, neither strike me as the one right solution. ". While I'm sure there are many people unwilling to restrict carbohydrates to the point of 'natural reduction in caloric intake', that does not mean carbohydrate restriction is not the best solution for those people. Just because a patient is unwilling to take the treatment does not mean the treatment is not effective or that the theory behind the effectiveness of the treatment is not correct.

    I don't buy that ALL obesity is related to refined carbs and sugar but I do suspect that it is probably the most common cause of obesity and high carb intake is probably the reason many if not most stay obese.

    Yes Taubes is a bit dogmatic about his theory but I do suspect that his theory is the one that holds up to the current body of experimentation better than the others. Guyenet's so called poking of holes in Taubes's theory has a few huge holes itself. For example, he claims insulin is a satiety hormone by citing a study that injects insulin directly into the brain of a baboon. How does that prove anything? He claims that insulin is excreted by protein and therefore cannot possibly be the issue but ignores that there is an accompanying excretion of glucagon.

    And one other point, about Taubes's statement that researchers have been using 'suboptimal intelligence'. One just needs to look at the cholesterol fallacy foisted on us by Ancel Keys to understand what he is talking about.

  8. Great post! BTW, I think anyone who thinks there is one right way to go wrt obesity should study this obesity system influence diagram for a good long while!

  9. Re Ellen's comment, I also like Harry Rutter's editorial (login required) for The Lancet's series on obesity. He argues that obesity is a complex problem, not a complicated one.

    Money quote: "The distinction is important. A complicated system might contain many different elements, with various interactions, but it is knowable and ultimately predictable: a Saturn rocket is not simple, but plans for it exist, and to calculate its trajectory and send astronauts to the moon and back is possible. A complex system does us no such favours. It is non-linear, subject to unexpected and unintended consequences, contains feedback loops, and displays emergent properties—it is more than the sum of its parts. This kind of wicked problem needs a different set of approaches to understand it and deal with it from those needed for issues that are merely complicated."

  10. Anonymous1:03 pm

    As has been repeated many times, any long term solution must be one that can be maintained long term. To be maintained long term, the way of eating must still be enjoyable. For a small percent of the population, low carb eating is in fact quite enjoyable and sustainable. For a larger majority, grain products are essential staples part of culture and tradition and to cut back drastically is not sustainable. For some Taubes' all or nothing approach to carbs is the long term ticket to managing weight, for many a more moderate approach to reducing refined carbs is more likely to be sustainable.

  11. Taubes and Guyenet theories are both contributing factors to the problem, but neither have recovered from gross obesity, and are both missing many of the critical elements.

    That obesity map (Beth's pointer) kinda shows part of the problem, but not the solution. The main part of the problem is misinformation, and wrong information, along with interference of hunger/ satiety signaling by the man made foods... Sugars especially fructose, grains, especially wheat (see Wheat Belly), and omega 6 industrial oils that should be considered lubricants and poisons, not part of the human foods.

    Once I got off all these, I could listen to the body signaling, and that helped. Responding correctly to the signaling, aka -learning what the signal is saying- is also a problem, given our social, environmental, food availability, and schedule fixation culture. It has been an education - sorting real information and marketing information - an ongoing struggle.

  12. Well said. Very sensible. I've been watching the debate in the blog-o-sphere as well and it's pretty interesting. As a person of middle age who is addressing some weight creep, I think we have something (but not all) to learn from each of these people.

  13. I think it is a both/and thing. The doughnut has fat and sugar and refined carbs (and the boss brings them in so regularly as a cheap way to boost morale...). The fast food meal has high palatability and carbs and fat, and fructose in the soda, and is so much easier than cooking after a long day's work. The weight creeps on slowly over the course of years, and a person wakes up twice the person s/he used to be. Just as there is no one ideal house for everyone, there is no one ideal body shape. I like your idea of finding the healthiest lifestyle you can enjoy, and living it.

  14. I've also been following this discussion various places. I struggled through Stephen Guyenet's posts on food reward, and it's not quite the same thing as palatability or bland taste, at least how I understood it. Maybe hyperpalatability, and dopamine reactions and food conducive to overeating, etc. As for Taubes, if he would stop demonizing all carbs, I might be able to stand his sanctimonious tone enough to read more of what he has to say, but probably not, I'm not into zealots.

  15. Curious if you caught the CNN special "The Last Heart Attack." Sanjay Gupta interviewed Dean Ornish and Caldwell Esselstyn, who both advocate extremely low fat diets as a means to prevent/treat heart disease. The evidence for their diets seems remarkably sparse, however.

    I took a quick look at Esselstyn's study. It involved 22 people and there was no control group. The treatment was the Esselstyn diet and cholesterol lowering medications to achieve total cholesterol 150 or below. 11 of the people dropped out by 5.5 years followup. Esselstyn's diet is very extreme -- no meat, fish, poultry, oil, dairy. It's probably healthier than the average Western diet, but I'm not convinced that it is necessary to be so restrictive.

    In any case, the evidence that the Ornish and Esselstyn approaches will make you heart attack proof, which is what the program seemed to be implying, is unconvincing.

    I hasten to add that I have nothing against vegan diets -- to each his own.

  16. Hi Marilyn,

    Esselstyn's is as restrictive, if not more so than Atkins' plan.

    Even if it did reverse heart disease, I'd wager the percentage of folks willing to live with it forever is very, very low.


  17. Great post, Yoni. I was at a conference a few weeks ago (on a totally unrelated but nearly as contentious topic), and on the back of the conference proceedings the organizers had printed a quote from Karl Popper in huge letters, as a reminder:

    "Whenever a theory appears to you as the only possible one, take this as a sign that you have neither understood the theory nor the problem which it was intended to solve."

    I think I'm going to make that my motto!

  18. They should include that quote at every conference!

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