A Calorie is Not A Calorie - A Discussion of Thermodynamics

[amwassil]

Paul, I survived to tell the tale. Although, I have to admit that I never expected such advocacy of CICO on this forum. I admit, though, that it did get to me being accused of not understanding the first law. Thanks.

[PaulL]

It does surprise me just how deeply CICO thinking permeates even these forums. Think, though, how much worse it must be elsewhere.

[atomicspacebunny]

Here’s my angle on CICO:

All your measurements can look correct and logical mathematically but you have no idea what is going on, on the other side of the fence?

You could be over over-supplying a system that already knows what to do and furthermore confusing it by trying to makes calculations we are not capable of understanding because of the vast cascade of the variables and the biological pathways involved?

Too much of one or two calories is going destabilize the system and give you what you think is a favorable result temporarily, but then it will start to switch rails in the long-term…

That said when you try to re-introduce the other required or missing part of the machinery, guess what? PERMANENT DAMAGE?

[KetoGolem]

This is not an inaccurate picture of what low-carb researchers actually do say. There are recorded lectures by Dr. Phinney, for example, in which he states that one of the reasons that a well-formulated ketogenic diet works appears to be because fatty-acid metabolism increases on such a diet. This is heresy, according to the energy-balance hypothesis that is the dominant nutritional paradigm.

Good point. I just couldn’t tell how much they were talking about. Phinney says it increases, so there too - how much? It all seems very vague and liable to enable claims from both sides, so to speak. Small increases of any nutrient often don’t make much difference. But even many strictly low-carb and fat-adapted people will gain weight eating “large amounts of fat” - it just has to be enough to do it. I don’t think we can generalize about anything from all this.

I certainly agree that lowering the insulin level can (and often does) make a significant difference for lipolylis,even a massive difference, so I disagree with the article’s statements about that. But this isn’t the same thing as being able to eat “a lot of fat without weight gain,” especially if they mean hypercalorically (and there too I couldn’t tell for sure what was meant).

George Cahill’s starvation experiments were written up in Starvation in Man, which was published in the late 1960’s or early 1970’s. His conclusions have not yet been refuted by later research.

I am totally lost here. Why did you bring this up? Did I say something against Cahill’s findings? All I can remember is that it was an important study and there was stuff in there about the body losing fat and protein… I remember seeing charts taken from that study on this forum but it’s been a long time.

I love that statement, awesome!

Taking these in reverse chronological order… That statement is only sometimes true (that “risk for obesity is primarily determined by total calorie intake”). I don’t doubt that the studies the article mentioned did have that as a finding, but we also know that insulin is a driver of change, often, and it looks to me like the article’s authors deliberately cherry-picked around any that demonstrated such.

In the OP of this topic I posted the link to an article by Feinman and Fine noting the characteristic feature, ie specifically ‘a calorie is a calorie’, of so-called CICO theory of dietary management violates the second law of thermodynamics because it ignores the observed fact that the macronutrient composition influences metabolic processing and resultant energy balance.

I have yet to read it, and it’s late here, I only glanced over it - I will read it in the future. And that’s quite a sentence there; like something I’d come up with. I do think you are missing the overall picture. “A calorie is a calorie” appears there, but you are the one inserting CICO - not the authors of that article (I did not see them address it, anyway). “Calories in, calories out” is a statement of two mutable quantities - there is nothing saying the quantities have to be the same nor that a single calorie has to be exactly the same in every way, versus another calorie. Everybody knows they come in different configurations, as a starter, no? I don’t see people arguing that. I do see people claiming that physics don’t apply, and this would definitely be a problem.

As critical as I am of the article in your post #92, it at least does address the energy balance - I think they miss the point about how insulin really can change things, but on a physical level they seem to be fairly sane about how the body works. I’ve yet to see whether the one in your OP does.

I also noted that the statement ‘a calorie is a calorie’ represents CICO as a whole since it is the fundamental characteristic of the theory and methods of dietary management based on it.

I think you are mistaking “calorie restriction as primary” - that weight loss paradigm, with the overall energy balance, and they are not the same. Just “cutting calories” works for some and of course does not work for some in the pursuit of weight loss, especially over the long term. The most frequent reason is (as you evidently know) because one’s metabolism can decline, changing the energy balance. This is a change also in “calories in, calories out,” but there’s nothing there that says ever individual calorie is indistinguishable from every other. Saying “a calorie is a calorie” really has nothing to do with the energy balance.

Likewise,

No - CICO is two quantities, not any statement of necessary equality. Look how many times ‘CICO’ comes up on this forum. But nobody is saying that all calories are exactly the same, with nothing more to be considered. Why CICO comes up on this forum is because of the question of what the energy balance is, and if it matters.

So, yes - it’s not that people are arguing about what “a calorie” is or one versus another. It’s physics - and we can talk about the thermodynamic laws to be sure - and the reason CICO comes up so often is not because “a calorie is a calorie.” The concept runs through several threads, i.e. a unit of insulin is a unit of insulin, a shekel is a shekel, etc. Saying that really doesn’t address anything at issue. It is the quantities of them, and the changing quantities, that matter.

I expected general agreement with the views I expressed as they are the generally accepted definition of CICO theory and diet management. Yet, I was attacked vehemently by several posters.

Because it’s as if you have some “crusade” against CICO and in your zeal you mischaracterise it. It’s often as simple as just disregarding the “calories out” part and the fact that it, as well as the “in,” can change.

You ought to find studies that address the energy balance and the changeable nature of both the “in” and the “out” if you want to address CICO.

In fact, I find it rather bizarre that I was attacked and ridiculed by certain posters for posting and agreeing with a paper that lends support to the Hormone hypothesis upon which the ketogenic diet is based.

Where is that? I’ve missed it thus far.

Yet, my critics here seem to be defending and advocating CICO on the basis that I have misrepresented it by not understanding the first law of thermodynamics and not appreciating the complexity and sophistication of CICO overall.

Again, I think the error in trying to see and state things too simply lies with those who are “anti-CICO.” I don’t know all what you mean about the first law, there. Can you state your understanding of it as it applies to human metabolism, in a few sentences? I’ll do it too - we all can. Gotta go for now; really getting biyatched by my wife.

[amwassil]

Because it’s as if you have some “crusade” against CICO and in your zeal you mischaracterise it.

Maybe it seems like a crusade. In my personal relationships I have known folks who stuggled with weight via CICO diets and mostly failed big time. Repeatedly. This affected them psychologically as well as physically. I have also read the accounts and tribulations of folks on this forum who have done the same. I’m a logical person, and something that fails repeatedly for many different unrelated and unconnected folks leads me to conclude that the method is flawed, not all those folks who tried the method. The first law of thermodynamics does not redeem the universal failure CICO. No one is going to eat a caloric deficit unto death.

Again, I think the error in trying to see and state things too simply lies with those who are “anti-CICO.” I don’t know all what you mean about the first law, there.

CI = CO means no weight change (neutral energy balance)
CI > CO means weight gain (positive energy balance)
CI < CO means weight loss (negative energy balance)

Show a discussion of CICO that says anything different, aside from my critics in this topic who seem to have developed their own ‘combo’ version of CICO that attempts to impute macronutrient complexity not mentioned by other CICO advocates. Other advocates and researchers make the point that macronutrient composition is irrelevant or insignificant to weight/fat considerations. See here (Instead, risk for obesity is primarily determined by total calorie intake.) and the linked citations.

I think you are mistaking “calorie restriction as primary” - that weight loss paradigm, with the overall energy balance, and they are not the same.

I understand the first law of thermodynamics. CICO uses calorie restriction to create a negative energy balance. It does not differentiate where the calories come from, since it considers all calories thermodynamiclly identical, 4.186 joules. A calorie is a calorie, after all.

I do think you are missing the overall picture. “A calorie is a calorie” appears there, but you are the one inserting CICO - not the authors of that article (I did not see them address it, anyway).

To what other weight/fat maintenance system than CICO does ‘a calorie is a calorie’ apply? The total interchangeability of one calorie for another is the essence of CICO. The insignificant effect of source macronutrients is the hallmark of CICO. A calorie is a calorie is CICO.

[atomicspacebunny]

To what other weight/fat maintenance system than CICO does ‘a calorie is a calorie’ apply?

What can the system DO endogenously that your already putting into it?

Endogenous Conversionary Synthesis:

• Make Glucose & Fructose?

• Make Non-Essential Fatty Acids?

• Make Non-Essential Amino Acids?

• Make Non-Essential Micronutrients/Vitamins?

‘a calorie is a calorie?’

CI = CO means no weight change (neutral energy balance)
CI = CO means weight gain (positive energy balance)
CI = CO means weight loss (negative energy balance)

What can the system NOT DO endogenously that your already putting into it?

Non-Endogenous Conversionary Synthesis:

• Make Essential Fatty Acids?

• Make Essential Amino Acids?

• Make Essential Micronutrients/Vitamins/Minerals?

”…A homogeneous mixture is a solid, liquid or gaseous mixture that has the same proportions of its components throughout any given sample. Conversely, a heterogeneous mixture has components in which proportions vary throughout the sample. …More

Maybe not having an overall picture of how a entire system really works, like is it an open system (is mass and energy leaving the system?) or a closed system (expansion and contraction?) then density (solidity), volume (capacitance) and thermal conductance (amount of heat required until sublimation).

Formula: p=m/V, or density § is equal to mass (m) divided by volume etc. (grapes to raisins)

Containment parameters, rate of flow etc.

So how much activity can happen within a given amount of space when you place a piece of mass into it, as matter can exist in three different states solid, liquid, gas (pure substances-mixtures-elements-compounds (molecules), homogenous-hetrohomogenous etc.

How long would it take for this volume and mixture of calories to turn from a solid==>liquid then into a gas? Time?

Thus ‘a calorie is (can be) a calorie?’

Or

‘a calorie (cannot be) a calorie?’

All calories (units of energy composed of a mixture of compounds, elements and substances) are inclusive or non-inclusive in the endogenous and non-endogenous (exogenous) system?

Density (mass) and Volume = PORTION SIZE?[•]

[•] Mass Per Unit Volume Divided by Timing (when should I eat again? should I slowly reduce in increments the volume in equal calories? “occasionally restrict elements of the diet?” or “occasionally pull axis 3?”[2]) Then maybe I won’t be so hungry? Or long-term sustainability (equilibrium)?

Dr. Peter Attia[2]

References:

[1] Does being in ketosis automatically translate to fat loss? NO - Dr. Peter Attia

[2] My nutritional framework - Dr. Peter Attia

[3] When somebody loses weight, where does the fat go?

[atomicspacebunny]

Taking these in reverse chronological order… That statement is only sometimes true (that “risk for obesity is primarily determined by total calorie intake”). I don’t doubt that the studies the article mentioned did have that as a finding, but we also know that insulin is a driver of change, often, and it looks to me like the article’s authors deliberately cherry-picked around any that demonstrated such.

I think it depends what we think a calorie is?

What is it actually?

If it is electrons within units of energy how do you know what those electrons are going to do in relation to insulin?

Do proteins, fats or carbohydrates have different electrons?

[PaulL]

I am totally lost here. Why did you bring this up?

I mentioned Cahill in a reply to that post of yours, in which you wrote, “I wonder what happens in true starvation.” So I was referring you to Cahill to find out.

I generally try to quote posts rather than rely on the Discourse thread-following features. I don’t know why I didn’t do that, in this particular instance, sorry. But if a post is written in reply to another post, you can always click on the previous poster’s icon at the top of the reply and re-read the original post. This is Discourse’s way of allowing people to follow threads within a topic. (If you click on the downward V associated with a quotation, it will reveal the entire post from which the quotation was taken, by the way.)

Likewise, you can jump to the responses to a post by clicking on the down-arrow below the post.

[ElmosUzi]

All your measurements can look correct and logical mathematically but you have no idea what is going on, on the other side of the fence?

The other side of the fence is part of CICO. If you don’t measure both sides then you “have no idea,” (at least for a while). Like with a household budget - you have to consider all of what’s going on. Dollars in, Dollars out. Or insert the currency of your choice. If you don’t keep track of expenditures, then obviously things are not what they should be, i.e. just saying, “But I have this much money coming in,” is not a complete picture. You have to consider expenditures as well.

You could be over over-supplying a system that already knows what to do and furthermore confusing it by trying to makes calculations we are not capable of understanding because of the vast cascade of the variables and the biological pathways involved?

No, the system doesn’t know what to do, given human behavior. It’s not infinitely adaptable; it can’t maintain a constant or “normal” or desired weight, necessarily (and/or the same for blood sugar), and that’s what brings most people to this forum.

It’s like you want to make things both more simple and more complex than they really are. More simple by just looking at “calories in” while not considering “the other side of the fence.”

More complex by saying “we are not capable of understanding because of the vast cascade of the variables and the biological pathways involved.” That’s not true - there are calories in (or ‘energy’ if you don’t like saying ‘calories’ or we could also say ‘grams’ or ‘ounces,’ etc.). And then there is metabolism, storage and excretion. Correct? Or are we missing a substantial, meaningful quantity there?

It’s really not that complex or ‘unknowable.’

Too much of one or two calories is going destabilize the system and give you what you think is a favorable result temporarily, but then it will start to switch rails in the long-term…

You have your own “unique” way with words and syntax, so I’m not sure what you’re saying. Taking it at face value, one or two calories isn’t going to meaningfully alter the situation, is it?

Then I think you are referring to people losing weight at first, and later stopping the weight loss or regaining weight. Sure, this happens. This is nothing against CICO. You’re describing two different conditions. You’re really talking about “calories out” changing, no? Well, nobody says it can’t change - by definition here it can change.

ie specifically ‘a calorie is a calorie’, of so-called CICO theory

This is a logical fallacy. You’re stating your conclusion (that CICO means ‘a calorie is a calorie’) in your premise (circular logic). In reality, the article does not mention CICO.

The article immediately explains what it means by ‘a calorie is a calorie’ - "that weight change in hypocaloric diets is independent of macronutrient composition."

Or later, “The most common meaning is that is it impossible for two isocaloric diets to lead to different weight loss.”

Correct me if I’m wrong - I think we can all agree that those two statements are false. But this is no “failure” of CICO. CICO can be a cause or a result.

An example of it being a cause - a person cuts the “calories in” enough and for a long enough period of time that they lose weight. The ‘in’ is below the ‘out.’ I think we can all agree that in that situation weight loss will indeed occur.

An example of it being a result - (with the statements from the article in mind) a person eats 2200 calories per day, with two different situations being considered. The first is 700 calories protein, 300 calories fat, 1200 calories carbohydrates. The second is 700 calories protein, 1500 calories fat. So, isocaloric but with different macronutrient composition.

In the first case, the person loses a small amount of weight over time. Their average energy expenditure was 2200 calories per day, and there was a very small amount of waste.

In the second case, the person loses a greater amount of weight. The difference in carbohydrate consumption made for less insulin response and a lower overall average insulin level. The body spent less time in “energy storage mode,” and the average energy expenditure was 2600 calories per day, and there was a very small amount of waste.

The numbers could be different, but here too I assume that we all can agree that such can occur. We are disagreeing with the article’s statements; we are saying that weight change may not be independent of nutrient composition, and that that two isocaloric diets can lead to different weight change.

Anybody that gives credence to the carbohydrate-insulin theory can only logically agree with the above. We have a more complete picture than do the two statements from the article. This says nothing against CICO. With the different composition diets, CICO did not predict there would be a difference in the weight losses, and it did not claim to predict it. In that situation, CICO was a result, not a cause. CICO didn’t “fail,” there. CICO reflected the change in energy expenditure, and the changes in the fat storage levels.

[atomicspacebunny]

No, the system doesn’t know what to do

Depends on the input?

Volume of input ====>system over-load===>storage capacity===>excess storage===>sublimation to oxidation===>time

[ElmosUzi]

Depends on the input?

You tell me. My point was that you said the system already knows what to do.

So, under what conditions are you wrong?

[atomicspacebunny]

So, under what conditions are you wrong?

If you reduced the in-put then you may have a more favorable out-put?

If you over-whelm the system then it may do things it is not supposed to do?

If you have two systems over-laying and integrating each-other, one that is electrical (what calorie counters rely on?) and the other is chemical, which system will dominate the other?

You could think of calories in the sense of photons (electrons) or as mass (matter)?

Atomic===>molecular===>subatomic (photons)===>gravity (nature’s weak force)

[PaulL]

This is a logical fallacy. You’re stating your conclusion (that CICO means ‘a calorie is a calorie’) in your premise (circular logic). In reality, the article does not mention CICO.

“Calories in, calories out,” sometimes also expressed as “a calorie is a calorie,” is shorthand for the notion that calories are fungible; i.e., that weight change is independent of macronutrient composition. Another shorthand phrase is “eat less, move more.” You are right that the notion is false, but to say that “that’s not what CICO means” is also wrong, because the passages you quote are the very definition of CICO.

I suspect that you are confusing CICO, the ideology, with the notion of “energy balance.” Please bear in mind that nobody (or at least nobody sane) questions the thought that gaining weight involves taking in more food than we metabolise or excrete, and that losing weight involves taking in less food than we metabolise or excrete. And that is true, whether the weight gained or lost is lean tissue or fat.

The term CICO, by definition, stands for the hypothesis that increased weight is caused by one kind of energy imbalance, and decreased weight is caused by an imbalance in the opposite direction.

The hormonal-response hypothesis, on the other hand, reverses the direction of causality. The body’s hormonal milieu determines whether weight will be gained or lost by manipulating appetite to regulate intake versus expenditure. Furthermore, according to this hypothesis, the hormonal milieu also determines whether the weight gained or lost will be in the form of lean tissue or fat. (And we know from experience that it is possible to gain lean tissue while simultaneously losing fat.)

So in effect, we are all arguing the same thing, it’s just that you are claiming that the term CICO “means” something that the people who use the term never use it to mean. I agree with you that the term should mean what you say, but that is not how it is used in the scholarly debate. So when people on these forums use the term in the way you don’t think it should mean, they are just following the standard practice, not jumbled in their thinking.

To reform standard terminology is an overwhelming task. I don’t advise even trying. A wag once pointed out that “the Communist Party of the 20th century was no more communist than the Christian Church of the Middle Ages was Christian” (I’m a Christian, by the way, and I agree with that statement). But to try to come up with different terms from what those institutions called themselves is futile; they called themselves what they called themselves, and we just have to deal with it. And the same with CICO.

[IdesOfMarch]

Saying, “a calorie is a calorie,” has no context. It’s like saying “a gram is a gram” or “a carbohydrate is a carbohydrate.”

So - can we get a good handle on the dietary context, is it possible to view human metabolism fairly completely, are we forgetting anything substantial if we say “yes,” do we need to measure or even care in the first place, is it “too stressful” to have the overall picture, and can we be satisfied with our understanding?

All right then.

The first law of thermodynamics does not redeem the universal failure CICO.

Yet again, this is massively illogical. You are absolutely kidding yourself. Even using your incorrect view of CICO, there are times that it proves out.

I suspect that you are confusing CICO, the ideology, with the notion of “energy balance.”

1. Consider “calories in, calories out.” Several people have pointed out that there are two quantities there. It is nonsensical to act like there is no relationship between them, i.e. there must be a comparison, a balance. Yet your statement implies that there are two different things, that CICO is not an energy balance.

2. Or, let us not worry about that, and proceed…

Please bear in mind that nobody (or at least nobody sane) questions the thought that gaining weight involves taking in more food than we metabolise or excrete, and that losing weight involves taking in less food than we metabolise or excrete. And that is true, whether the weight gained or lost is lean tissue or fat.

Quite reasonable.

The term CICO, by definition, stands for the hypothesis that increased weight is caused by one kind of energy imbalance, and decreased weight is caused by an imbalance in the opposite direction.

Okay, let’s go with that. As in your previous paragraph, nobody sane would argue with the proposition that under certain conditions a predictable weight gain or loss will be observed. We can construct examples that undeniably bear this out. Or we could just do it.

The hormonal-response hypothesis, on the other hand, reverses the direction of causality. The body’s hormonal milieu determines whether weight will be gained or lost by manipulating appetite to regulate intake versus expenditure. Furthermore, according to this hypothesis, the hormonal milieu also determines whether the weight gained or lost will be in the form of lean tissue or fat. (And we know from experience that it is possible to gain lean tissue while simultaneously losing fat.)

Very reasonable here too; I agree that this can and does happen. Here too, we can construct examples that undeniably bear this out. In the case of many individuals on this forum, we can testify to those hormonal effects.

But they don’t have to be the driver. Some people have enviously fast and effective insulin response, and it’s much more just the quantities of in and out.

So in effect, we are all arguing the same thing, it’s just that you are claiming that the term CICO “means” something that the people who use the term never use it to mean. I agree with you that the term should mean what you say, but that is not how it is used in the scholarly debate. So when people on these forums use the term in the way you don’t think it should mean, they are just following the standard practice, not jumbled in their thinking.

Thus, even when we begin with the incorrect view of CICO - the one you correctly note that people should not use - it’s still sometimes correct. So it’s silly to talk about any “universal failure.” Let’s look at the complete picture at that point and say that “Sometimes it’s right and sometimes it’s wrong.”

[Festus]

Saying, “a calorie is a calorie,” has no context. It’s like saying “a gram is a gram” or “a carbohydrate is a carbohydrate.”

Exactly. Just one example: we all know that a calorie of fat will weigh less than a calorie of carbohydrate.

[MarkGossage]

there are times that it proves out.

In that case it cannot be a universal hypothesis and once disproved is gone for good… black swans etc.

[amwassil]

This for some of our friends here who have convinced themselves that I don’t know what I’m talking about. No one, including me, denies ‘calories in calories out’ is a thermodynamic statement of the first law.

‘CICO’ on the other hand is a diet management hypothesis. The idea behind CICO (the hypothesis) is that you can eat whatever you want, but as long as the number of calories you eat is less than the number of calories you burn you will lose weight because you’re in an energy deficit. A necessary corollary is that the energy contained in any specific calorie is the same regardless of the macronutrient source of the calorie. Hence, a calorie is a calorie no matter whence it derives and has the same overall energy effect as any other calorie. Saying so is not a tautology, it’s a claim that macronutrient sources of calories don’t matter metabolically. Only the energy matters. This is the accepted definition of CICO, not my misunderstanding of it. You can easily verify with Google.

Nothing in the above paragraph denies the general principle of energy balance. Nor that if you eat less than burn you will lose weight. Nor if you eat more than burn you will gain. Nor that folks lose weight on CICO diets. Nor claims that CICO is wrong because is violates the first law. (My point starting this topic was to introduce the argument that CICO hypothesis is wrong because it violates the second law.)

CICO (the hypothesis) simply claims that ‘calories in and calories out’ matters and nothing else very much. Now, of course, advocates of the CICO hypothesis talk about food ‘quality’. They’re not out there recommending that we eat only granulated table sugar. They recommend foods based on the current FDA Food Guidelines (or the equivalent in other countries). No one, including me, accuses CICO advocates of ignoring the macronutrient qualities of various foods. What they ignore, or at best simply downplay as insignificant, is that macronutrients are metabolized differently and that differential processing results in different implications on overall energy balance. Different foods may be more ‘healthful and nutritious’ but their calories remain the same as calories from granulated table sugar. And their effect on weight loss or gain is exactly the same.

CICO (the hypothesis) advocates also consider the alternative Carbohydrate-Insulin (Hormone) hypothesis of diet management as overrated at best, and nonsense at worst. If you doubt this, just do a review of CICO literature. You could start here.

Now, obviously, there are folks on this forum who want to combine the best of both worlds, the strict adherence to energy balance as claimed by CICO and the obvious differential effects of hormonal and enzyme regulation on both energy and health. I wish them well in their attempt. But currently these folks, as well intentioned as they may be and I presume they are, remain lone voices crying out in the CICO wilderness.

Oh, just in case these folks don’t realize it, the hormonal hypothesis includes all the energy balance stuff they seem so concerned defending in CICO.

[OldDoug]

120+ posts in - has anybody read and understood the article in the original post?

"A calorie is a calorie" violates the second law of thermodynamics

There it is again. Maybe I’m just getting old or maybe it’s hard to understand or maybe the authors go about it in a roundabout way, or all of those… Here’s what I got:

They (the authors) mention that some people think that macronutrients make no difference by themselves, as to weight gain or loss. The authors say that thermodynamics affects this.

They’re going to look at metabolic advantage from low-carb diets. They say the 1st Law of Thermodynamics is relevant - conservation of energy.

They say the 2nd Law is also relevant - that there is dissipation. (Of course; the 2nd Law is about entropy, and entropy tends to increase, to go from a more ordered state to a less ordered state, and this process won’t be 100% efficient; there will always be losses/dissipation. And energy only flows one way, as in the case of heat from hotter to colder.)

Then they say, “something (negative entropy) is lost and therefore balance is not to be expected in diet interventions.” Okay, WTF? Why say that? 2nd Law ~~> Entropy ~~> Energy Loss. Not hard to understand. So, “entropy happens.” But why talk about “losing negative entropy”? Isn’t that just the same as “entropy”?

And at this point I haven’t even gotten through the first paragraph yet.

So, does anybody really get this article? @amwassil, @LeroyJenkins, @PaulL, @ElmosUzi, @KetoGolem, @IdesOfMarch, etc., Anybody - Everybody. What, exactly, is the authors’ conclusion and how do they arrive at it?

[amwassil]

What, exactly, is the authors’ conclusion and how do they arrive at it?

Conclusions

A review of simple thermodynamic principles shows that weight change on isocaloric diets is not expected to be independent of path (metabolism of macronutrients) and indeed such a general principle would be a violation of the second law. Homeostatic mechanisms are able to insure that, a good deal of the time, weight does not fluctuate much with changes in diet – this might be said to be the true “miraculous metabolic effect” – but it is subject to many exceptions. The idea that this is theoretically required in all cases is mistakenly based on equilibrium, reversible conditions that do not hold for living organisms and an insufficient appreciation of the second law. The second law of thermodynamics says that variation of efficiency for different metabolic pathways is to be expected . Thus, ironically the dictum that a “calorie is a calorie” violates the second law of thermodynamics , as a matter of principle.

Application of ΔG’

To understand the implications of “a calorie is a calorie,” that energy yield could be path-independent and the same for all diets consider that it implies that carbohydrate and protein are equivalent fuels as shown in Figure 1

The diagram indicates that, because it is a state variable, the free energy (ΔG’) for Path 1 must be equal to that for path 2 + 3. If the ΔG’ values for path 1 and path 2 are taken to be their calorimeter values, they will be approximately equal (~4 kcal/g, path 1 corrected for ureagenesis). This means that ΔG’ for path 3, the conversion of protein to carbohydrate (also corrected) must be about zero. There exists at least one condition where this is not true, the standard state; it is generally considered that gluconeogenesis from one mole of alanine requires about 6 ATP [13,14]. Of course free energies are concentration dependent, so in vivo values will differ from standard state values but they are continuous functions of the concentrations and there will be numerous conditions under which ΔG’ is not zero. In other words, assuming that protein and carbohydrate are energetically equivalent leads to a contradiction.

My summary: Different processing of different macronutrients results in different energy balance end states. More energy gets dissipated in some metabolic processing than in others. The ‘calorie is a calorie’ claim fails because it is based on the erroneous presumption that in all cases the energy balance end state is in equilibrium and is reversible. It is not.

[anon81060937]

@amwassil
Do carbohydrates increase thermogenesis or are they thermocooling?