(versión en español: pincha aquí)
There is a dogma in the nutrition field that says “fat accumulation is determined by the difference between the calories you eat and the calories you burn, no matter the source of those calories.” In a more concise way, it is said that for losing weight or becoming fat “all that matters is the energy balance” and that “a calorie is a calorie”.
Other people, like me, however, think that this dogma is false and that counting calories is nonsense, as absurd as adding apples and oranges. 400 kcal of sugar don’t have the same effect on our body as 400 kcal of butter. They do produce the same heat in a calorimeter, but they do not cause the same effect on a human being. That makes sense, right? This point of view raises the ire of some people, and we are accused of denying the laws of thermodynamics. They are physical laws of the universe! I’ve come to read (see the first note at end of the document), and they call us zealots for denying the compliance with these laws (which we don’t).
I am aware that those from outside the world of nutrition live in deception. If you haven’t spent some of your time on this field, if you haven’t spent a minute of your life thinking about what calories are, most likely you still think that the dogma is true. No surprise there. I’ve been in that situation and don’t consider myself an idiot because of believing that. I never questioned the dogma.
But a different case is to hear nutrition experts say that advantages (real or not) of a diet like mine, like producing greater weight loss with the same amount of calories as other diets, “are not compatible with the laws of thermodynamics. ” Well, that, coming from alleged experts in nutrition, is really serious, as it is assumed that these people have indeed spent a couple of minutes thinking about it. If these people really are honest when they talk about “incompatibility”, when they realized the extent of their mistake, they surely would want to disappear from the face of earth. Or delete entries from their blog, as one of them is used to do.
It’s really very simple. In a very very simplified way, the energy expended is derived from ingested food and burnt body fat:
What I spend = what I eat + the fat I burn
Let’s say a person normally spends 2500 kcal per day and today he/she ingested 3000 kcal. The dogma says that there are 500 kcal/day that will make you fat. And according to the dogma:
2500 = 3000 + (-500)
where the negative sign means that we gained body fat instead of burning it. Very important: the first law of thermodynamics says that the sum of the blue and green terms must be equal to the red term. The equality must be fulfilled. Something that is true in this case, and therefore this energy partition is possible, because it doesn’t violate the law. Simple, right?
Okay, now I suggest that those excess 500 kcal can change the total energy expenditure of that person, increasing it by the same amount, 500 kcal, (the excess is lost in the form of an additional heating of the body) and therefore there will be no fat accumulation.
3000 = 3000 + 0
Are the laws of thermodynamics violated here? No, the sum of the blue and green terms is equal to the red term. There is no violation of the laws of thermodynamics. This second energy partition is also possible, because it doesn’t violate these laws, either.
In summary, the idea is that these “extra” calories can not disappear, they surely have to go somewhere (so says the first law of thermodynamics), but thermodynamics don’t tell you where they go, to body fat or to an increase in energy loss as body heat.
And what determines if the fate of that “overeating” (if such a thing does exist) is to be converted into body fat or to be lost as heat? That is, what determines whether excess food will make us fat or not?
The first law of thermodynamics is not going to give you an answer for that.
Let’s say I propose that “the composition of the diet, not calories, is key in determining whether you lose or gain body fat”. What is important right now, in this little dissertation, is not to know whether this statement is true or false, but to understand that it is possible! and that in no way implies a violation of the laws of thermodynamics. The laws of thermodynamics only say that the mathematical equality we’ve seen before must be fulfilled, but they don’t impose a specific value for the terms of the equation. When you use a diet A you can be accumulating fat, while another diet (with exactly the same total calories) can cause the excess calories to be lost as heat. In both cases the equality is fulfilled. In both cases the laws of thermodynamics are satisfied.
Perhaps with diet A we have: 2500 = 3000 + (-500)
and with diet B we have: 3000 = 3000 + 0
Both diets have the same total calories, and gaining body fat, or losing it, may depend on what you eat. It’s simple to understand, right?
Well, from now on, whenever you read that “Food A is not more fattening than Food B because it has the same amount of calories”, you will see it like I do, and you will stop reading what that person wrote or listening to what they say, because you will know they are ignorants. Now you understand that counting calories is meaningless. Why would you care about the total calories of a the diet if you don’t know where those calories will be used? The total calories of food, if you don’t know about the energy partition your body is going to apply, provide no useful information to you.
And when you read sentences like these (they come from two different people):
“I believe that the truth is far simpler and far more compatible with the laws of thermodynamics ”
“the insulin hypothesis is not consistent with basic thermodynamics”
you will wonder, as I do, how can a person who is professionally involved in the nutrition field have a misconception as profound as that, something that is so obvious and that only takes five minutes to understand it?
Just one more thing: the dogma that “fat accumulation is determined by the total calories you ingest, and not by diet composition” is false, as has been proved in many scientific experiments. For example, the experiments I explain in the pages linked below this line are impossible according to the Calories In Calories Out dogma. The experiments are real or the CICO dogma is true, but both can’t stand at the same time. If a theory is contradicted by the scientific evidence, it is false.
I wrote about these ideas a while ago (Thermodynamics for dummies), but when I read another comment about the “incompatibility” with thermodynamics, this time coming from a vegetarian, one of those who go through life giving lessons to us, it seemed to me it was time to write again about it.
NOTE: The page that says we are violating laws of the universe has been removed . The URL was:
But the author published it here too:
It’s quite simple. If you have a caloric deficit, you lose weight. If caloric balance is positive, you gain weight. Energy balance is a direct representation of the first law of thermodynamics, the one that says energy can neither be created nor destroyed. We’re not talking about a hypothesis here, or even a theory, but a physical LAW OF THE UNIVERSE. Ever hear of the law of gravity? A law is something scientists are so damn sure of there is no disputing it. You can’t deny the first law of thermodynamics any more than you can deny the fact that if you jump out of a high-flying airplane without a parachute, gravity will not be your friend. (Note to fans of The Secret: the “Law of Attraction” is not a real scientific law.)
And yes, I do know there are bestselling low-carb authors who question this law. They present themselves as “controversial.” They assert that years of accepted science is wrong. Let me ask you a question: The next time you get into an airplane, would you rather it was designed, built and tested in a scientifically proven manner, or a controversial one?
NOTE: I have tried to simplify the explanation as much as possible, even at the risk of committing inaccuracies. The false dogma of “energy balance” is a simple idea (even the dumbest person understands it) and to prove it is false it seemed fit to also use simple explanations.