A Calorie is Not A Calorie - A Discussion of Thermodynamics

[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?

[amwassil]

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

Is a Calorie Really a Calorie? Metabolic Advantage of Low-Carbohydrate Diets

Conclusion

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.

[PaulL]

Do carbohydrates increase thermogenesis

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.

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”?

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.”

[amwassil]

Here’s one for any lurking data nerds:

Effects of variation in protein and carbohydrate intake on body mass and...

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.

[amwassil]

Diet induced thermogenesis

Discussion

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.

…

[OldDoug]

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.

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.”

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.

Here I do disagree.

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

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.

[OldDoug]

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

Noted.

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.

Cheers.

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.

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

August Fat Burnin'

Darcy, I think the biggest thing that’s wrong with ‘CICO’ is that we often think of it as so simple, when it’s really not, since hormonal balances can drastically affect our metabolism and tendency to store fat. The “calories out” is there, but it’s everything that’s burned, excreted, and stored.

That was 3 years ago.

[amwassil]

@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.

[PaulL]

Now my head hurts.

[LeroyJenkins]

World peace is the opposite of capitalism. So it’s the end result. Not what’s missing.

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.

To satisfy the mind therefore it stops asking irrelevant questions.

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.

To satisfy the mind therefore it doesn’t care about “want” material possessions.

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

To satisfy the mind therefore it doesn’t keep searching for the perfect stimulant, food, diet, joke, etc…

A desire for blissfulness.

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?

[OldDoug]

It is important to understand that it is the second law that drives chemical reactions .

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.

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.

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.

[PaulL]

But let’s not get this thread shut down because of politics.

Very sound advice.

[amwassil]

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.

Why do proponents of CICO (the weight management hypothesis) consistently declaim opposition as denial of the first law of thermodynamics? As if CICO = the first law. There are many reasons to condemn CICO (the weight management hypothesis) that have nothing to do with the first law.



If you read nothing else in this paper, read the Discussion

Discussion

To the best of our knowledge, this study is the longest follow‐up investigation of the changes in metabolic adaptation and body composition subsequent to weight loss and regain. We found that despite substantial weight regain in the 6 years following participation in “The Biggest Loser”, RMR remained suppressed at the same average level as at the end of the weight loss competition. Mean RMR after 6 years was ∼500 kcal/day lower than expected based on the measured body composition changes and the increased age of the subjects.

[atomicspacebunny]

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.

Thinking of this in the terms of voltage, wattage, amperage, resistance and impedance rather than gas?

1 calorie is 4.184 J (1 Electron volt (eV) = 1.602176565 x 10-19 joules (J))) <==== how much of this is already on-board (muscle, liver glycogen, sorbitol fructose pathway in the brain and gluconeogenesis from dietary protein and body parts; nitrogen balance?) before you put more into it?

How much time would it take going from a solid to a liquid and then a gas?

Does it matter if it’s a protein, fat or carbohydrates?

NO it does not!

If we remove macro nutrients, vitamins minerals and trace elements from the picture?

And you eat one donut a day, you will go into ketosis anyway? As you lose body fat or skeletal muscle mass you can keep adding donuts?

Why? It is because the volume and density is not enough to sustain the previous system or energy balance so it will go into ketosis and burn/oxidize body fat or stored lipids any way?

All the processes that happen with eating only protein and fat will occur with eating only a carbohydrate also?

A calorie is a calorie?

Just like only eating animal proteins can do magical things when you play with IGF-1, but when you keep trip hammering it long-term, it will do the polar opposite. It’s the blackest magic you can practice with dietary nutritional science and comes with severe consequences If you believe in the law of cause and effect?

And also there are calories within calories when your talking about carbohydrates?

Us human beings are nothing more than a vapor that includes bones and teeth.