Taubes-Guyenet debate. Conclusions

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A lost opportunity to teach Taubes how he is violating the First Law of Thermodynamics

This debate was the perfect opportunity for Stephan Guyenet, PhD, to explain to Gary Taubes that Taubes’ hypothesis violates the First Law of Thermodynamics. But he didn’t do it. The reality was that in 2h30m of debate Guyenet didn’t even try to do that. It’s been a long time since Guyenet claimed that the insulin hypothesis was contrary to the laws of thermodynamics. My bolds:

The insulin hypothesis is not consistent with basic thermodynamics . Stephan Guyenet, PhD

if insulin doesn’t increase energy intake (if anything, the combination of insulin and amylin that the pancreas releases in response to carbohydrate decreases it), and doesn’t decrease energy expenditure, then how exactly is it supposed to cause energy accumulation in the body as fat? There is no energy fairy. Stephan Guyenet, PhD

Has Guyenet found those magical fairies? Guyenet in 2011 was a “big bad wolf” who was ready to eat, but in 2019 he has been a shy chicken on the same topic. But I haven’t heard him say that he was wrong.

How has Guyenet justified the dogma that the caloric content of the diet is what determines our body fat gain/loss? His argument is that the best scientific experiments do not find differences between diets. And he has used the meta-analysis by Hall and Guo as proof of that. If any reader remembers a different argument about this topic in the debate, please let me know. I don’t remember a different one.

a recent meta-analysis reported no meaningful differences between low-fat and low-carbohydrate diets and claimed to have falsified the CIM. However, this analysis of very short studies (most <2 weeks) suffers from major methodological flaws that preclude a definitive finding. Most importantly, the authors did not account for the physiological processes involved in adaptation to a low-carbohydrate diet over time, confounding transient with chronic effects. Ludwig and Ebbeling

Ok then, I have commented the details of this meta-analysis, and we have seen that the claim that there are no differences between diets is untrue. There are differences: looking at the experiments one by one, the conclusion is that calories do not determine body fat gain. What we find in these data is that in the short-term (15 days or less), in general the diet lower in carbohydrates is more fattening, but if the diet is followed at least six weeks, high-carb diets are more fattening. This is what the meta-analysis’ data say, assuming that Hall and Guo have correctly collected the data from the experiments they included in their review (I didn’t check their data, I only represented them versus the duration of the experiments). And in this meta-analysis there are no long-term data. This is important: in science, the conclusions must be limited to the conditions in which data has been obtained. You cannot extrapolate to the long term, as Hall and Guyenet do, because that is deceiving, specially if the clear trial duration dependency is ignored, as they do. In summary, we have seen that the evidence presented by Guyenet doesn’t show that the results are the same regardless of the composition of the diet. Even if he says it does.

you got backlash from the community that’s looking for ways to say they were right all along. Gary Taubes

Note how certain people, such as Guyenet and Hall, have transitioned from the defense of an ideology believing that it is what is deduced from an unbreakable law of physics, to the defense of that same ideology believing that it is what is deduced from scientific experiments (see). And they have made this transition without ever acknowledging the erroneous basis of their beliefs. And both of them know that it’s wrong and both of them know that a lot of people still believe in that ideology for the wrong reasons. The result of their silence is that the energy balance pseudoscience is still alive. The general population is still being deceived and they’ll continue to think that the ideas such as that we get fat because of a “caloric surplus” or that the only way to lose weight is to create a “caloric deficit” are indisputable. And these two guys are accomplices in this deception. Their silence feeds the deception. Each year, new graduates in dietetics and nutrition will arrive to the labor market trained in this pseudoscience and convinced that they are defending a law of physics. And who knows how much longer will we continue to treat obesity with quackery, the hypocaloric diet, because of attitudes like those from Hall and Guyenet. Guyenet accused Taubes of doing harm for not being an advocate for the official dogmas (e.g. calories, physical exercise, etc.). Guyenet and Hall are the ones who harm, giving support to a pseudotherapy that was born directly from human stupidity.


After watching the debate, how relevant would you say Guyenet thinks is the mechanism of obesity that Taubes defends? Zero on a scale from zero to ten?

Let’s remember Guyenet’s words:

[SG 4m] adipocytes do not regulate the size of adipocytes […] what regulates the size of adipocytes is the brain

10 days before the debate Guyenet attacked Taubes with the argument that Taubes claims his mechanism is the “primary” mechanism by which obesity happens, without considering that other mechanisms may be relevant. Guyenet has double standards.

Guyenet’s pseudoscience is refuted by scientific evidence

[Joe Rogan 2h10m] But you’re saying that the same amount of carbohydrates, sugary carbohydrates versus vegetable carbohydrates, sugary carbohydrates are going to be more fattening.

[SG 2h10m] No, no, I didn’t say it was independently of calories. It is entirely dependent on calories.

We have seen hundreds of scientific experiments in this blog that refute Guyenet’s beliefs. I’ve included links to almost 100 blog posts that comment those scientific experiments in the fifth part of my analysis.

The magic hypothesis

At the beginning of the debate Guyenet said that he was going to explain his hypothesis. But he didn’t do it. He just delivered his dogmas: brain, leptin and overeating. But, what is the physiological mechanism by which the adipocyte receives the order to accumulate fat (which according to him is because we have overeaten)? Does anyone remember him explaining that mechanism in the debate? What hormones participate? Does insulin participate? Guyenet’s hypothesis is the magic hypothesis. It happens and do not ask how it happens. It’s magic! He found the magic fairies!! And this guy claims to be the defender of scientific evidence.

Why does Guyenet’s hypothesis lack a physiological mechanism? Because his beliefs are a pseudoscience. Pseudosciences are characterized by the absence of physiological mechanisms that can be tested. For decades, guys like him have been absolutely sure that they were defending an inviolable law of physics, and, therefore, they believed that they didn’t have to prove anything about how their “theory” worked. Moreover, they thought to be above second-level hypotheses that were about “mechanisms” (see). The erroneously interpreted tautology was their “mechanism.” Taubes has left them high and dry.

Taubes’ version

Taubes has made two different contributions in his books:

  1. He has pointed out the errors in the energy balance pseudoscience.
  2. He has proposed an alternative hypothesis based on the action of insulin. And, in particular, he has presented arguments against sugar.

As I said, the advocates of the energy balance pseudoscience have transitioned from claiming that their beliefs were rightfully derived from the First Law of Thermodynamics to the defense of the very same ideas with completely different arguments (see). And they have changed the fundamentals of their beliefs without ever recognizing the huge error that they are making in the treatment of obesity.

one of my other problems with the conventional paradigm is that it keeps morphing, you know? Every time a new finding comes up, it morphs in a way that tries to account for that finding without having to reassess the basic assumptions of that. David Ludwig

Taubes has been always right in his explanations about the wrong basis of the energy balance paradigm. In this regard, Taubes’ arguments are faultless.

As for the insulin, or carbohydrate-insulin, hypothesis, it is a simple hypothesis that surely doesn’t explain all the situations, but at least it is based on an actual physiological mechanism, in contrast to Guyenet’s pseudoscience. If Taubes’ hypothesis doesn’t explain some situations, the logical next step is to improve the hypothesis, not to discard it and to go back to the same pseudoscience that we have been suffering for almost a century. Or it should be replaced with another hypothesis that is proved to be more useful or more correct. Let’s not use here the false dilemma fallacy: if Taubes’s hypothesis were proved incorrect, that wouldn’t prove correct the energy balance pseudoscience.

NOTE: if I am not wrong, Taubes believes that it is a good idea to start with a simple hypothesis, following Occam’s razor philosophy. And then improve the hypothesis to fit the real-world data. But he thinks that if you start saying that it is a complex and multifactorial problem, no progress should be expected. Nevertheless, I may be wrong in this interpretation of his views.

Go to the fifth part
Go to the fourth part
Go to the third part
Go to the second part
Go to the first part


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