The First Law of Thermodynamics
I've been fighting off a cold so begging off housework in favor of goofing off at my blog today. Lots on my mind so I've been rather prolific!
I get tired of hearing this misstated time and again by both people who should know better and those ill equipped to comment on such matters, but who do anyway. I'll abbreviate The First Law of Thermo as TFLOT.
Calories In = Calories Out + Energy Stored is a fact. This boils down to simple conservation of mass in the end as I discussed in a bit of a rambling post HERE. From hereon out I'll use CI and CO for calories in and out respectively.
The first "error" many are quick to point out is that TFLOT applies to a closed system, and as we all know humans are not closed systems. True enough. But all we need do is expand our system a bit to include our surroundings and voila! We're back to a closed system for the purpose of energy balance equations. But we don't need to even do this for the most part when we realize that the Calories Out term is multifactorial and all we need is to have a term to account for such things as heat lost to the surroundings.
Some of the more thin skinned in the Calorie Denial movement may be offended by Lyle's language, but to date this happens to be the best, comprehensive, layperson-friendly treatise on the web concerning Energy Balance: The Energy Balance Equation by Lyle McDonald. He painstakingly dissects each term and there's really no sound argument against any of his points.
This brings me to the second "error" made most often by Deniers, that conversion of energy to thermal energy constitutes an entropy loss requiring Second Law principles be applied. Ummmm..... NO! The evolution of heat in an exothermic (heat liberating) chemical reaction is dealt with quite well applying TFLOT principles. Energy "lost" to non-conservative forces (e.g. friction) in mechanical contexts is also calculated by simple applications of the energy balance equation. TEF and thermal losses to the environment are handled quite well by the TFLOT. Given as most humans maintain a relatively constant temperature and modern humans live in relatively temperature controlled environments most of the time, this part of our "CO" term remains relatively constant. But, it has been shown that we can lose weight by tolerating periods of shivering cold, and there's nothing in that violating TFLOT, indeed it supports it yet again because it increases the energy we must expend to stay warm.
But what of Dr. Eades ridiculous assertion that if TFLOT held we could gain weight sitting in a warm room? He said that folks, in the comments of one of his absurd responses to Anthony Colpo, I just don't think it's that important to track down the link. Now perhaps there is an organism somewhere on this planet that harnesses thermal energy to "fix" mass and does so, but I'm not aware of one. Plants use radiant light energy through photosynthesis to synthesize larger carbon molecules from CO2 which is probably the closest analogous process, but plants in no way violate TFLOT in doing that. The radiant energy is part of their CI.
When Feinman and Fine, and Eades and Harcombe and myriad others claim we're not at equilibrium with our environment so TFLOT need not apply and thermogenesis demonstrates a need to apply Second Law principles, they are not making sense. We are not steam engines attempting to harness thermal energy to do mechanical work through the expansion of a heated gas. Thermal energy is a perfectly valid term on the CO side of the equation. And TFLOT is applied to systems that are not in equilibrium all the time!
I've said before and I'll say it again, the whole equilibrium free energy stuff is largely irrelevant in the human body because most of our chemical reactions are occuring far from equilibrium being catalyzed by enzymes whose levels are under hormonal control. And at any given time energetically unfavorable reactions, such as fatty acid synthesis, are occurring because we have the ability to harness energy liberated from one reaction to drive another. It is reasonable to conclude, as well, that if entropy losses occur, these too, are relatively constant.
Bottom line: Heat is not entropy and it is perfectly capable of being dealt with on the CO side of the Energy Balance equation. Since we don't even attempt to harness thermal energy, it need not even be considered in terms of Second Law.
Humans can do a lot of amazing things, but we can't make something from nothing any better than the next species ;-)
I might be wrong, but I don’t think Taubes et al are implying this, although it often seems so. Taubes argues – if I understand him correctly – that hormonal factors dictate EI and EO. In other words, hormonal factors decide how much energy we take in, how much energy the body expends and what substrate the body takes. In his view, a morbid obese individual fed a low calorie, high carb diet would eat his organs and die fat. This would not violate the laws of thermodynamics. But I no longer think this is what would happen.
Feed a fat person potatoes ad libitum and the fat person will lose fat mass and improve ‘parameters of health’ ;-).
Melchior, one of the problems I have with GT is that he seems to be constantly changing what it is he's actually stating. In verbal form (interviews and lectures) he talks a lot about storing calories and "excess" calories, but then defaults back to the insulin driving this. And in his latest blog post he's claiming that when calorie restricted diets work it's ultimately because of the carb restriction. After condescendingly mocking researchers for not exercising proper control in their studies, he goes on to cite Shai and that somehow we're to ignore that the results of that study didn't control for calories. *sigh*
Anywho, this rant was mostly about 2nd Law. It's a whole lot of bunk. Hall and Chow are my heroes :p
And I'm very glad that you commented about the strange way GT changes what he says in interviews, giving different impressions of what he believes and is trying to get across compared to what he writes. It drives me nuts! The shiftiness is really odd.
Perspiration. That it is. Each gram of perspiration that evaporates from skin carries away 540 calories.
I have just not known how to take these people seriously when they say stuff like this.
In a safety engineering course I took, the first week we were doing mass/energy balances on fireballs. If a plant is leaking "x" litres/s of propane / butane / hexanol, calculate the heat flux "y" distance away.
it was ALL
(mass/energy in) - (mass/energy out) = accumulation
and then taking differentials & integrals of that
From the first day of classes to the last day, chemical engineering is ALL first law, occasionally 2nd law thermodynamics. I bet Mechanical is the same. And although Elecs don't may not refer to Kirchof's rules as the 1st law, it is.
In case the readers here don't know, industrial -accident fireballs are well known for their equilibrium-state, closed-system characteristics.
Think engieering. Think car engines, hot water heaters, HVAC, plumbing, sewage systems, the electrical grid. Those were all designed using 1st law. None are closed, none are equilibrium.
I've never heard of an equilibrium, closed system engineering design. Such a thing would be useless - it wouldn't do anything.
And all Chemical engineering, I would bet most if not all Mechanical engineering and most Electrical engineering design and analysis boils down to the 1st law. Somewhere (most likely everywhere) in engineering project you'll find
"in -out = accumulation".
There may be 100 to 1000 "in" pieces (imagine the large vessels you see in moves with the hundreds of pipes going all over the place) and the same "out" pieces, so that equation can stretch out over several pages, but I guarantee it's there.
@Kuntsa: Note the use of the word relatively and perhaps I should perhaps add something like "averaged out over time". My point was that our "basal" energy expenditure to maintain temperature should be relatively constant because we don't let our bodies get out of a pretty narrow range of temperatures and we don't generally don't spend long stretches in extreme temperature environments. That basal metabolism varies little day-to-day (I've seen figures around the 2% mark for fluctuations) would support this. We also do have to remember the calories you cite are actually equivalent to ~1/2 food calorie which are actually kilocalories. Welcome to the Asylum & thanks for your input!
@Frank, I think that last comment is spot on. I also believe Taubes appeals to the rebel in many of us and the whole speak truth to power and all that jazz.
The equilibrium thing demonstrates a fundamental misunderstanding of the topic. To be fair it probably stems from applications of thermo to reversible chemical reactions and such, but the whole deltaG going to zero stuff baffles me. The article was published in Nutrition journal. Hall and Chow would have a field day with it I suspect.
Feinman once described a boulder falling off a cliff and when it gets to the bottom G = 0 and he wondered where the energy goes? An engineer, no less, on Jimmy's forum said that the beauty of entropy is that it doesn't require us to explain where the energy goes, it's just gone.
One particularly funny tactic is how Eades and Feinman will wax poetic about how difficult thermo is and how they lack a complete understanding ... the implication being that if it is so complex for them, nobody else could possibly get it.
I think you are probably right about them being influenced too much by working with reversible chemical reactions and such.
Frank >> It's clearly the Dunning-Kruger effect at work here.
Clearly Feinman and Eades have some Dunning-Kruger going on where thermodynamics is concerned, but for most laypeople I’m not sure it is really Dunning-Kruger (as I understand it anyway). I think for many it is more just a combination of confirmation bias and “wow, look at all those endnotes”. I can see your point though for those who take it upon themselves to lecture to others.
The other issue is direct FFA absorption has a different efficiency than FAA - ketone - use.
Human efficiency is only about 27%, so a small change downward makes a big difference. (L.F. Hoffer)
On a 60% carb diet, I am weight stable at 1600 C/d and loose weight nicely on 1800 C/d and 20% Carbs. CHow and Hall exclude both the above noted issues.
But what do I know.
don't try to blame insulin for it, please
> Feinman and Eades have some Dunning-Kruger going
Or "you can believe anything if your paycheque depends on it"
Although avoiding saying "I was wrong" is a pretty strong motivator too
 I thought I was wrong once, but I was mistaken
But even taking what they say at face value, they are essentially arguing that we lose more energy to entropy losses from fatty acids than carbohydrates. Leaving aside thermogenic factors, since the vast majority of the reactions to generate energy from macros are shared (Krebs and Electron Transport Chain) we would be talking super-minute differences. This notion that "fat burning" and "carb burning" are so fundamentally different is absurd.
@justdoinglife: Atwater's factors were for bioavailable energy. It's amazing that considering how they are averages and all that they hold up quite well when intake and expenditure are controlled and measured as well as fat vs. lean mass gained or lost. But I suspect they hold up so well because, as I stated above, most of the energy we extract from the three macronutrients comes out of the same metabolic pathways.
Does anyone really think Taubes, Sisson and Eades (to name a few) would be blogging if not to help sell books, supplements and other products? C'mon! I don't fault them for that per se, but in all things of this nature the smart consumer needs to consider this.
I think GT passed the point of no return writing the new book. He's apparently been told by many more knowledgeable than I that his theories are wrong at least by early in 2010. He'll use the excuse that he simplified the "science" even more to make it lay-friendly and if the responses from his fans are any indication, they'll gobble it up and dismiss it because hey, I lost weight eating low carb! The alternative would have been to fess up, re-direct attention to his newest target of sugar and move on. But there's less money to be had there, and no doubt his publisher would have had a fit.
The second law of thermodynamics pertains to closed systems where neither matter nor energy leave the system. In earthly biological systems, the constraint of being closed is not met.
That is, the earth is not a closed system if vast amounts of energy enter the system from the sun. This energy can be used to create complicated systems, such as living organisms, without violating the second law.
The thermodynamics of living systems is nonequilibrium thermodynamics that is more complicated than the near equilibrium thermodynamics taught in undergraduate chemistry and physics courses.
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