Conclusion
It is increasingly clear that the idea that âa calorie is a calorieâ 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. âA calorie is a calorieâ 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.
A Calorie is Not A Calorie - A Discussion of Thermodynamics
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, donât 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 ânegative entropyâ is convoluted and obtuse, and Prof. Feinman usually speaks much more clearly than that. Try substituting âorderâ for ânegative entropyâ 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 âorderâ instead of ânegative entropyâ. Itâs possible, however, that âorderâ conveys connotations they wished to avoid; it is also possible that in the conversation that this paper is part of, ânegative entropyâ 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 ânegative heat.â Likewise, we speak of âsunriseâ and âsunsetâ as shorthand for âthe earth rotated to bring the sun into viewâ or â. . . to take it out of view.â
And I use âCICOâ as shorthand for âa damnfool notion that has no relevance to life as we actually live it.â 
Hereâs 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.
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.
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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, âThereâs going to be a lossâ is a given, considering the 2nd law, but that applies to carbs and fats as well. It could be more concisely stated as just âThe 3 macronutrients end up with differing amounts of available energy, versus an initial calorie-for-calorie basis.â
Here I do disagree.
The only way to be correct is to give enough context. Letâs say, âFrom a thermodynamic view, a calorie is a calorie.â That avoids all the BS.
Iâve never seen anybody say âthe end state is reversible.â Thatâs not an argument.
âthe erroneous presumption that in all cases the energy balance end state is in equilibriumâ - Again, thereâs 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 âin some cases the end state can be in equilibrium,â then we can be correct.
However, there always will be an overall energy balance. Thatâs not ânecessarily equal,â thatâs just all of whatâs 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.
Noted. 
Cheers. 
Thanks for saying this, Paul. Clearly, people approach the issue in different ways.
That was 3 years ago.
@OldDoug The author includes some âcontextâ 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, ÎG, 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 âa calorie is a calorieâ then
(1) ÎG1 + ÎG3 = ÎG2 + ÎG3
since both ÎG2 and ÎG3 are ~4 kcal/g (calorimeter measurements)
(2) ÎG3 = 0
However, in the case noted by the author, ie alanine, ÎG3 â 0, therefore the assumption of energy/entropic equivalence fails.
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 worldâs people would pick capitalist countries. But letâs not get this thread shut down because of politics.
Maybe, but that sounds like a given consciousness that doesnât 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. 
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 âsearchingâ you mention is happiness, for some. Being happy is some pretty serious genius, eh?
Sure. And thatâs 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.
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 followâup 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 âThe Biggest Loserâ, RMR remained suppressed at the same average level as at the end of the weight loss competition. Mean RMR after 6 years was âź500 kcal/day lower than expected based on the measured body composition changes and the increased age of the subjects.
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 itâs 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. Itâs 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.
Hey, we are back. 
Short version reply: because the sometimes faulty weight management hypotheses you speak of are not really at issue on this forum, while the first law of thermodynamics is violated, both directly and by implication, in a substantial number of posts by a substantial number of people on this forum.
A logical query. I think this does go to âthe larger scientific picture,â critical thinking, and examining ourselves as a group.
From what I have seen, you want to limit CICO to âweight management hypothesesâ that can be knocked down easily. âEat less, move more,â or âCount calories, cut calories.â As simple as that; nothing more required, and so forth.
I think everybody is aware of these notions and that to this day they exist in literature and in the minds of some people âout there.â Yet the members of this forum donât really make those arguments nor advance them as universally suitable hypotheses. If thatâs not true, then who do you see advocating for them?
There have been at least four threads in the last month that encompass similar themes to this one. What posts have you seen that argue for those hypotheses?
So then, the first law of thermodynamics. Plenty of posts that deny things, there.
(Okay, so not for human metabolism?)
(I donât have a huge quarrel with this one. It does seem to denigrate things on the basis that âscience is hard,â however, while I think a more overarching truth is that - even if its hard for us to count something - the scientific laws will still be there.)
(Who says itâs not thermodynamic?)
(Same thing - âthe science is hard, so physical laws donât applyâ approach.)
(The first law of thermodynamics remains well satisfied, nonetheless.)
(This was meant in humor and good-naturedness, so once again I canât be too critical. As above, here Iâd only say that (as ElmoUzi noted) everybody should intuitively know that the laws of conservation of energy and matter will be satisfied, and that they apply as much in our lives as anywhere else.)
@amwassil Michael, in your own posts you have kept away from directly denying the first law, there, to the extent Iâve read. Itâs more that youâve sometimes had the attitude that just because it may be difficult to measure energy, it then follows that considerations of the energy balance are faulty.
I donât think thatâs the right way to say it. It definitely isnât going to âevadeâ the first law, regardless of what âsideâ of a discussion one is on. This should be a necessary logical conclusion in the first place. So, no matter what we say about CICO, acting like the first law doesnât apply will be incorrect.
Itâs incorrect to say, âTo lose weight, all anybody needs to do is count calories.â
Itâs certainly incorrect to say or imply that the first law of thermodynamics isnât true, doesnât matter, will be violated by such-and-such, etc.
No, I think youâve established yourself as a master. 
I felt compelled to give a âLikeâ to that post. I sense a lighthearted and playful sense in there somewhere. 
And -
- are we talking about outright âmagicâ?
For a minute there, I had visions of our fat cells not actually having fat inside them, and being encased by parts of other cells (that do have fat in them). 
(Why donât we have a âWitchdoctorâ icon?)
NCC-1701 Trekkie
To be totally serious, yes.
This is part of it too.
This is good, this brings us all closer together (I think ) in our thinking. I for one would always vote for âhardâ science over everything else. This forum is better than any other I know of, but it has its share of opinion stated as fact, logical fallacies/moving the goalposts, generalizing from the particular, etc.
This is part of it too.
Well, actually, proper nutrition science is extremely difficult, as Gary Taubes points out. To conduct a true double-blind experiment is impossible in many cases (people can usually tell whether most of the food they are eating is carbohydrates or fat, for example). And forcing people to eat a certain way and making sure they eat that way all the time is difficult and expensive. Do you want to be locked up in a metabolic ward for three or four months? And a proper long-term study would last at least two years, so . . . .
This is why we rely on epidemiological data, short-term experiments with small study populations, and small effects that may be statistically significant but not necessarily clinically relevant. If youâve got some way in mind of getting us better data, Iâd bet a lot of people would be interested to hear it.
If you cannot measure accurately, you donât know what you are doing. Thatâs elementary carpentry, as well as elementary physics.
I think that when some of us make points about the inaccuracy of measuring energy intake and expenditure, itâs in response to people who think they can calculate their macros and their energy use to the last calorie. And the point of refuting that view is that energy in and energy out need to come within 0.2% of each other orâby the standard CICO viewâthe person will gain or lose fat. (And thatâs assuming the standard figure of 3500 kilocalories to a pound of fat is correct, which it probably isnât.)
As Taubes points out, we are speaking here of one mouthful of food, or less. So how are you going to know whether this mouthful should be your last or if the previous one should have beenâgiven the impossibility of making precise measurements? So our point is, why not give up the chase for precision and relax? Or better yet, why not let it all be handled by the same bodily mechanisms that served our ancestors so well?
And yet, that is the notion for which the acronym CICO is shorthand. Many people repeat this incorrect idea, including government health authorities the world over. Not to mention such respected bodies as the WHO, the American Heart Association, the American Dieticiansâ Association, the American Diabetes Association, and their equivalents around the world.
You and we are actually in agreement about what CICO should mean. The problem is that the rest of the world uses the term âCICOâ and the phrases âa calorie is a calorieâ and âeat less, move moreâ in a way that neither you nor we agree with. So when you see disparaging remarks about CICO on these forums, please bear in mind that we are disagreeing with them and agreeing with you. We are not disagreeing with your notion of what CICO should mean, we are disagreeing with how they use the term and agreeing with you that they are using it wrong.
Keto activists maintain that the First Law certainly operates, but that it says nothing about the direction of causality. We assert that the notion that the sheer quantity of calories eaten determines what our body does with the food we eat is inaccurate and misguided. To say this is certainly not contrary to the laws of thermodynamics.
Energy balance is indeed a factor in what happens, but the bodyâs hormonal response to the foods we eat is going to determine both the rate of energy expenditure, and also whether we will gain or lose lean tissue and/or gain or lose fat stores. Moreover, it is whether we are in gain or loss mode that will determine the energy imbalance, not the reverse. (And furthermore, if we are in fat gain mode, the hormonal response will also determine where in the body the extra fat will get deposited.)
All that people who advocate a ketogenic diet are saying is that the energy-balance model is too simplistic. The First Law of Thermodynamics alone cannot explain how someone like Sam Feltham was able to able to eat 5000 kilocalories a day for a month on a low-carb, high-fat diet and not get fat. (He did gain a few pounds of lean tissue while losing a few pounds of fat at the same time. So he ended up a few pounds heavier and a bit thinner. But overall, his weight remained remarkably stable.) His similar experiment with a high-caloric, high-carb, low-fat diet yielded much different results. So obviously, while the laws of thermodynamics apply, they cannot be the whole story.
I think several posters seem to define CICO - the hypothesis and diet/weight management systems - in a manner influenced by their knowlegde and possibly reluctant acceptance of at least some, if not all, of the insulin/hormone hypothesis that is the basis of keto. Theyâre essentially trying to combine both into something they can intellectual accept as valid. I can understand that, since keto actually works long term and CICO diets have a long term fail rate of 99+%. Hence they keep harping on the first law of thermodynamics, which no one denies, and add whatever hormonal influences and effects that they can not ignore because they explain the reality of metabolic management better than simple calories in and calories out.
I have no objections to theyâre doing so and in fact wish them well in their efforts. However, they persistently criticize those of us who disagree as simplifying and misunderstanding REAL⢠CICO when we actually state the mainstream understanding and interpretation. I for one quote and paraphrase the actual things proponents of CICO say about it, using the same terminology and understanding of that terminology. I know others here do so as well. We are not misunderstanding CICO and our critics simply undermine their own credibility by harping on it. Long upthread I challenged one these critics to cite something/anything that supported his interpretation and use of CICO terminology that contradicted my use. He has yet to do so. On the other hand, I have posted multiple citation from CICO researchers and commenters that use the terminology exactly as I do.
