A Calorie is Not A Calorie - A Discussion of Thermodynamics

(Bunny) #122

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)

(Bacon by any other name would taste just as great.) #123

“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.

A Calorie Is Still A Calorie - Why Keto Does Not Work :confounded:
(Ideom) #124

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

All right then.

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.

  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…

:+1: Quite reasonable. :slightly_smiling_face:

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. :smile:

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.

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.”

(Hagen) #125

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

(bulkbiker) #126

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

(Michael - When reality fails to meet expectations, the problem is not reality.) #127

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.

(Doug) #128

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

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…:neutral_face: 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? :face_with_raised_eyebrow::smile: 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?

(Michael - When reality fails to meet expectations, the problem is not reality.) #129


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.


Do carbohydrates increase thermogenesis or are they thermocooling?

(Michael - When reality fails to meet expectations, the problem is not reality.) #131


It is increasingly clear that the idea that “a calorie is a calorie” is misleading. The calorie content may not be as predictive of fat loss as is reduced carbohydrate consumption. Different diets (e.g., high-protein/low-carbohydrate vs. low-protein/high-carbohydrate) lead to different biochemical pathways (due to the hormonal and enzymatic changes) that are not equivalent when correctly compared through the laws of thermodynamics [6]. Unless one measures heat and the biomolecules synthesized using ATP, it is inappropriate to assume that the only thing that counts in terms of food consumption and energy balance is the intake of dietary calories and weight storage. Recently, Feinman and Fine concluded: " Metabolic advantage with low carbohydrate diets is well established in the literature… Attacking the obesity epidemic will involve giving up many old ideas that have not been productive. “A calorie is a calorie” might be a good place to start [31]." However, there will be metabolic accommodations and one cannot assume that the metabolic advantage (i.e., greater weight loss compared to isocaloric high-carbohydrate diet) will stay the same over a long term. The ideal weight loss diet, if it even exists, remains to be determined, but a high-carbohydrate/low-protein diet may be unsatisfactory for many obese individuals.

(Bacon by any other name would taste just as great.) #132

Thermogenesis is the heat cost of a chemical reaction. All reactions generate some heat; this is an expression of the Second Law of Thermodynamics, the law of entropy. No reaction can suck more energy out of the environment than it produces; that would decrease entropy, which never happens.

Doug, don’t blame yourself for not readily grasping the meaning. Entropy is a tricky concept in and of itself, and it has to be spoken about carefully, to prevent misconceptions from arising in our thinking. That said, the term “negative entropy” is convoluted and obtuse, and Prof. Feinman usually speaks much more clearly than that. Try substituting “order” for “negative entropy” wherever it occurs, and see if it helps.

I suspect that this article is written in response to something, and I bet it would make more sense if we had the other article in hand. They also want to emphasise that something gets lost in the process of a chemical reaction, and they could have written “order” instead of “negative entropy”. It’s possible, however, that “order” conveys connotations they wished to avoid; it is also possible that in the conversation that this paper is part of, “negative entropy” has already been used, so they were stuck with it.

Sometimes it is just necessary to speak or write in a convoluted manner in order to be precise. For example, in everyday conversation, we speak of cold as a positive force, but to speak precisely, we should probably refer to it as “negative heat.” Likewise, we speak of “sunrise” and “sunset” as shorthand for “the earth rotated to bring the sun into view” or “. . . to take it out of view.”

And I use “CICO” as shorthand for “a damnfool notion that has no relevance to life as we actually live it.” :grin:

(Michael - When reality fails to meet expectations, the problem is not reality.) #133

Here’s one for any lurking data nerds:

Conclusion: Low-carbohydrate, high-protein diets favorably affect body mass and composition independent of energy intake, which in part supports the proposed metabolic advantage of these diets.

(Michael - When reality fails to meet expectations, the problem is not reality.) #134


The main determinant of DIT is the energy content of the food, followed by the protein fraction of the food. The thermic effect of alcohol is similar to the thermic effect of protein.

Diet induced thermogenesis is related to the stimulation of energy-requiring processes during the post-prandial period. The intestinal absorption of nutrients, the initial steps of their metabolism and the storage of the absorbed but not immediately oxidized nutrients [15]. As such, the amount of food ingested quantified as the energy content of the food is a determinant of DIT. The most common way to express DIT is derived from this phenomenon, the difference between energy expenditure after food consumption and basal energy expenditure, divided by the rate of nutrient energy administration [16].

Theoretically, based on the amount of ATP required for the initial steps of metabolism and storage, the DIT is different for each nutrient. Reported DIT values for separate nutrients are 0 to 3% for fat, 5 to 10% for carbohydrate, 20 to 30% for protein [16], and 10 to 30% for alcohol [6]. In healthy subjects with a mixed diet, DIT represents about 10% of the total amount of energy ingested over 24 h. When a subject is in energy balance, where intake equals expenditure, DIT is 10% of daily energy expenditure.

(Doug) #135

Agreed, Michael, no question about it. If we are looking at available energy, then (with protein, as an example) there will be more of a loss in digestion/processing, leading to less available energy afterward. Not arguing with you here - but it bugs me that the 2nd law need be brought into this. Essentially, “There’s going to be a loss” is a given, considering the 2nd law, but that applies to carbs and fats as well. It could be more concisely stated as just “The 3 macronutrients end up with differing amounts of available energy, versus an initial calorie-for-calorie basis.”

Here I do disagree.

The only way to be correct is to give enough context. Let’s say, “From a thermodynamic view, a calorie is a calorie.” That avoids all the BS.

I’ve never seen anybody say “the end state is reversible.” That’s not an argument.

“the erroneous presumption that in all cases the energy balance end state is in equilibrium” - Again, there’s no context for this. Nobody is trying to tell you the end state will necessarily be in equilibrium - to do so would deny the possibility of weight gain/loss. If we say “in some cases the end state can be in equilibrium,” then we can be correct.

However, there always will be an overall energy balance. That’s not “necessarily equal,” that’s just all of what’s going on. The 1st law takes care of that. Even the article in your original post says that the 1st law applies to the systems considered in nutrition.

(Doug) #136

Noted. :smile:

Cheers. :slightly_smiling_face:

Thanks for saying this, Paul. Clearly, people approach the issue in different ways.

That was 3 years ago. :smile:

(Michael - When reality fails to meet expectations, the problem is not reality.) #137

@OldDoug The author includes some ‘context’ in the illustrated example of gluconeogenesis converting a quantity of protein into glucose. The paragraph immediately preceding the example and diagram (Figure 1) which I posted above, explains:

It is important to understand that it is the second law that drives chemical reactions. The first law is a bookkeeping law and tells us that the total energy attributed to work, heat and changes in chemical composition will be constant. It does not tell us whether such a reaction will occur, or if it does, what the relative distributions of the forms of energy will be. To predict the tendency of the reaction to occur, we must employ the second law that says the entropy must increase. In a chemical reaction, at constant temperature and pressure, the entropic and energetic effects are combined into the change in the Gibbs free energy, ΔG, whose sign predicts the direction of reaction, and whose magnitude indicates the maximum amount of work realizable from the reaction.

Applied to the diagram of gluconeogenesis if true ‘a calorie is a calorie’ then

(1) ΔG1 + ΔG3 = ΔG2 + ΔG3
since both ΔG2 and ΔG3 are ~4 kcal/g (calorimeter measurements)
(2) ΔG3 = 0

However, in the case noted by the author, ie alanine, ΔG3 ≠ 0, therefore the assumption of energy/entropic equivalence fails.

(Bacon by any other name would taste just as great.) #138

Now my head hurts. :grimacing:

(Leroy) #139

Then you should consider how people are treated in many non-capitalist countries. No human system is perfect, but if people got to pick, retroactively, to pick where their families were from and where they would be born, then most of the world’s people would pick capitalist countries. But let’s not get this thread shut down because of politics.

Maybe, but that sounds like a given consciousness that doesn’t really like the fact of its consciousness, i.e. it sees such mental activity is suffering. Other people love randomness and take great joy in it.

Sounds really Buddhist. So, that mind desires to not have desires. :yum: It still involves desire.

Constantly being unsatisfied does suck. Being happy is really the aim, whether a person knows how to get there or not. However, that very “searching” you mention is happiness, for some. Being happy is some pretty serious genius, eh?

(Doug) #140

Sure. And that’s true for all the macronutrients and every other chemical deal going on in the body. It should never be a debate, same as for not denying the 1st law when it applies.

This is true. The CICO arguments on the forum are not rooted in the admittedly faulty perceptions of some people about how to lose weight. The issue on the forum is mostly people trying to deny the 1st law.

(Bacon by any other name would taste just as great.) #141

Very sound advice.