Guyenet in his labyrinth

The CICO hypothesis says, in a nutshell, that when our energy intake is greater than our energy needs, the excess energy is accumulated as body fat (see, see).

The carbohydrate-insulin hypothesis says, in a nutshell, that an abnormal insulin secretion can directly affect the “entrapment” of fatty acids in our adipose tissue, in which case the changes in the energy expenditure and/or energy intake are not the cause of the accumulation, but just a possible (not necessary) consequence of the accumulation (see, see).

The graph below make it clear that both hypotheses propose opposite causalities:

Is it possible that sometimes our body behaves as the CICO hypothesis predicts, but sometimes its behaviour is more like what the carbohydrate-insulin hypothesis predicts? I think so, but let’s not fall into a false dichotomy between these two hypotheses: sometimes the behavior resembles what CICO predicts, but it is possible that other times the loss or accumulation of body fat is caused by the changes in the adipose tissue itself, perhaps caused by insulin, but perhaps caused or affected by physiological factors different from insulin. In this second option, changes in both the energy intake and the energy expenditure are, as we have seen in the previous graph, possible consequences, not causes, of gaining or losing body fat (see).

Let’s consider the following argument:

When you eat more calories than you burn, the excess calories are primarily shunted into your adipose tissue. Your adiposity, or body fatness, increases. It really is as simple as that

“It really is as simple as that”

Would you say that the author of that argument is explaining the mechanism by which, according to him, we accumulate body fat? He is considering only one mechamism for the accumulation of body fat, right?

Let’s consider another argument:

for insulin to cause fat gain, it must either increase energy intake, decrease energy expenditure, or both

According to the argument above, the only mechanism the author allows for insulin to be fattening is to work according to the CICO hypothesis. This argument says that insulin can not make you gain body fat by acting directly on your adipose tissue, as the carbohydrate-insulin hypothesis proposes. That option is not even discussed.

OK then, the two previous quotes are from Stephan Guyenet, PhD: one taken from his blog and another taken from his book. Would you say that he defends the CICO hypothesis as THE mechanism that explains why we get fat? If that is the case, you are probably mistaking him with another gentleman who is also called Stephan Guyenet, PhD, because Stephan Guyenet, PhD is against proposing hypotheses that explain why we get fat, without considering that other mechanisms may be relevant :

— Stephan, are both hypothesis 100% mutually exclusive?

— They are mutually exclusive, but only because Gary believes that his mechanism is the “primary” cause of obesity and other mechanisms are basically irrelevant.

So the gentleman who wrote a book that explains why we eat “too much”, not how insulin makes us fat by affecting directly our fat tissue, actually believes that it is inappropriate to defend hypotheses as the primary explanation for why we accumulate fat . He would never do that. As a proof that he would never do that, here we have a third argument where he does that again:

When calorie expenditure decreases and calorie intake increases, the energy balance equation leaves only one possible outcome: fat gain. We gained fat as we ate more calories than we needed to remain lean, given our physical activity level. In other words, we overate.. Stephan Guyenet, PhD

And this is the same gentleman who wrote an article arguing that the causality of the carbohydrate-insulin hypothesis is not possible! (see). Now he says that it is possible, and compatible with his ideology, because he is not dogmatic like others. What is your true opinion, then or now?

Let’s see another argument from Guyenet in which he makes clear that he believes insulin is irrelevant and calories are what matter:

So even though insulin temporarily suppresses fat burning and the release of fat from fat cells when you eat carbohydrate, at the end of the day if you ate the same number of calories you end up with the same amount of fat in your fat cells either way. You now know more about insulin than many popular diet gurus. Stephan Guyenet, PhD

And we know that Stephan Guyenet, PhD has always appreciated the carbohydrate-insulin hypothesis:

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

Cynicism: lie and/or defense of the indefensible with absolute impudence.

What hypothesis has been used for almost a century in a hegemonic way to treat obesity, using the fraudulent argument that it is an indisputable idea that drinks from the udders of the almighty laws of physics? But Guyenet, PhD, is against hypotheses that are proposed as the “primary” explanation for why we get fat if other possible mechanisms are regarded as irrelevant. An advocate of CICO would never do that. Guyenet’s nerve redefines cynicism.

A word of warning for CICO believers: Guyenet, PhD, does not defend CICO with arguments and, instead of that, he moves the goalposts , by accusing Gary Taubes of promoting an alternative hypotheses as the “primary” explanation for obesity. Is that really all he can say to defend the hypothesis that has been imposed on all of us dogmatically accross the world for the last 80-100 years?

I already warned those who believe that CICO is a law of physics that they have run out of gurus to follow. Please, walk on the catwalk to reach phase 2 of CICO beliefs. Do not stop and do not get close to the borders.

A warning for the CICO believers: the guru has left you in the lurch!!

Let’s see more examples of people who say that the energy balance is important but the physiology of the adipose tissue is irrelevant. I am quite sure these opinions upset Stephan Guyenet, PhD. Any time soon he will criticise phase-1 CICO believers.

1. “As long as there is an energy deficit, macronutrients play a secondary role”

2. “The insulin response will NEVER supersede the overall caloric balance of a diet”
3. “THE TRICK in the scientific studies of the Ketogenic, Paleolithic, Zone, or whatever, is to create an energy deficit to make the diet work. In order to deceive people, fad diets divert attention to “metabolic distractions,” such as hormones, insulin, glycemic index, macro-nutrient proportions, etc “

4. “The balance calories ingested minus energy expenditure determines your body weight”

5. “Hormones influence hunger & energy intake. The foods you eat influence hormones”

6. “A ketogenic or low-carb approach does not work because it creates metabolic magic or the ketones give you superpowers, it often works because it decreases your appetite”

7. “for reasons that are backed up by observation, inference, logical fallacy and straw men, apparently he’s decided that living creatures are magical beings that live independently of the laws of physics and thermodynamics.” Yoni Freedhoff

Yoni Freedhoff says that to talk about causalities different from CICO’s is to pretend that we are “magical beings that live independently of the laws of physics and thermodynamics”. It seems to me that Freedhoff doesn’t consider other mechanisms different from CICO’s. For sure Guyenet is not happy about Freedhoff’s opinion.

8. “for all practical purposes “a calorie is a calorie” when it comes to body fat and energy expenditure differences between controlled isocaloric diets varying in the ratio of carbohydrate to fat.”Kevin Hall, PhD

Kevin Hall, PhD has created mathematical models of obesity that are 100% CICO. His computer models consider de facto that the physiology of the adipose tissue is irrelevant (see, see, see, see, see, see). Is this the peaceful and positive coexistence of hypotheses that Stephan Guyenet, PhD defends? Moreover, when Kevin Hall, PhD says that “regain occurs only because interventions wane over time” (see), it does not sound like Kevin Hall, PhD is open to the idea of mechanisms other than CICO being relevant. Does he?

But, uh, Guyenet says that the extremist is Taubes because he claims that his hypothesis is the hypothesis that explains everything. CICO believers like Guyenet, PhD would never do that. They would never do that for a whole century. They would never do that for a whole century defending an erroneous hypothesis that leaves no room for other hypotheses because we have been tricked into believing that CICO is an indisputable law of physics. They would never be doing that right now accross the world. What are you telling me, Guyenet? What a magnificent straw man you have created, Guyenet. What a magnificent medal of moderation you gave yourself, Guyenet. This guy is the dictator who, from his throne, claims that the opposition parties, which have never been allowed to be legal parties, what they really want is to impose a dictatorship in the country. This is impudence and cynicism.

For the most clueless people, I insist that what Stephan Guyenet, PhD is saying is that he does not believe that CICO’s causality is indisputable. He explicitly admits that behaviors that don’t follow CICO are possible. He even criticises those who only contemplate one mechanism as possible. And he does not dare to defend CICO by mentioning the First Law of Thermodynamics.

NOTE: there is a long list of BS arguments used by Stephan Guyenet, PhD to make people believe that insulin is not fattening by acting directly on the adipose tissue (example, example, example, example, example, example). But now he presumes to be an open-minded person who believes that the insulin effects that he has systematically denied are indeed possible and can be accepted and coexist with his beliefs. Can you guess who has claimed over and over again to put the “final nail in the coffin of the carbohydrate-insulin hypothesis” (example)? Well then, now we find out that Guyenet was all this time a fan of the carbohydrate-insulin model. I am not sure I can believe him. 

NOTE: “Accuse the other side of what you are guilty of” is a well-known disinformation strategy. It is often attributed to Joseph Goebbels, but I am not sure that this attribution is correct (source).

Further reading:


“Lo que no comprende la gente es que CICO es complejo, muy complejo”

No conseguimos que funcione porque es complejo.

¿Suena razonable? Sí, suena razonable. Pero es sólo apariencia. El problema de CICO (Calorías que Entran Calorías que Salen) no es que sea complejo, es que es una hipótesis inválida, i.e. obtenida mediante razonamientos erróneos.

Las mismas personas que argumentan que CICO no es útil porque es complejo, afirman que CICO se cumple. Lo que en apariencia es una postura crítica con CICO, admitiendo complejidad y dificultad en la puesta en práctica, es en realidad no cuestionar esa pseudociencia.


Decir que CICO se cumple “sí o sí” equivale a negar la existencia de una hipótesis diferente de la Primera Ley de la Termodinámica. Y eso es falso, como he explicado extensivamente en el blog. En casos como el de este señor, parece simple desconocimiento del tema, como reconoce en este tuit:


CICO NO es la Primera Ley de la Termodinámica. CICO NO se cumple sí o sí.


  • Hipótesis CICO: “El balance calorías ingeridas – calorías gastadas determina el peso”. Óscar Picazo
  • Primera Ley de la Termodinámica: “La energía ingerida acabará almacenada en el cuerpo o expulsada del mismo, pero no puede desaparecer sin más”.

La hipótesis CICO establece —de forma injustificada— que sólo 2 de los 3 términos de la ecuación explican las variaciones de nuestro peso/grasa corporal. Eso no se deduce de la Primera Ley de la Termodinámica. CICO y Primera Ley de la Termodinámica NO son lo mismo.

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