More on Calories: A Gallon of Gas is NOT A Gallon of Gas? ... And Other Silly Thermodenyic Arguments

Richard Feinman announced on his Facebook page a little while ago that he is writing a book on Thermodynamics, and because every now and then he pops up in the hilarious Facebook threads featuring Fred "Super Slow" Hahn, Feinman's FB page is one that's interesting to pop in on from time to time.  Such was Feinman's response to a request from Ian Lane whose blog tagline is "For the frustrated few who want only the truth."  Sigh.  So the request was for Feinman to provide feedback on one of Lane's blog posts, to which Feinman responded (paraphrasing) 'TL;DR, I've been at this for decades Sonny, read my papers!'

The Energy In a Gallon of Gas Changes?

That last paragraph is the crux of the problem.  When a glucose molecule is broken down to CO2 + H2O, the chemical potential energy released amounts to roughly 4 kcal per gram.  This is CI:  "calories in".   This potential energy, taken on when one consumes and absorbs food molecules, doesn't change depending on what happens next. 

According to the How Stuff Works website (not the most academic of sources, but useful for illustration),  a gallon of gas contains roughly 130 million Joules of energy which can be "tapped" by combustion with oxygen in the air.  This does not change depending on what combustion engine I use the gasoline in.  What I can do with that energy changes, but if I put a gallon of this gas in (a) a motorcycle, (b) a midsize car, (c) a fullsize truck or (d) my weed whacker, the "calories in" to each of these machines and their engines remains the same.   For the sake of completing the analogy, each of these items will weigh approximately 6 pounds more after I've added a gallon of gasoline to them (though I'm not sure "d" takes that much ... work with me).  This same gallon of gas will take "a" much further than "b" and both further than "c", and it accomplishes a different thing entirely in my weed whacker, but this doesn't change the amount of energy contained in the chemical bonds of the gasoline.  

Which leaves us to Feinman's focus on substrate cycling.  This is part of "calories out".  Conveniently, this is something that would be virtually impossible to calculate.  Limited carbohydrate stores are cycled in and out of glycogen, fats are cycled back and forth between the triglyceride and free fatty acid forms, and various amino acids are converted and/or metabolized in various paths.  You have gluconeogenesis and de novo lipogenesis.  Then you have paths that produce lactic acid and ketones that can be metabolized.     I say "conveniently" because at this point any focus on this minutia seems to be a deliberate distraction from what we observe in metabolic chambers and tightly monitored metabolic ward studies.  That is, all of the above are part and parcel of the "CO" term that is our basal metabolic rate.   The energy cost of all energy-requiring syntheses is "CO", and we get that energy from "CI".   

A gallon of gas is a gallon of gas.  

Period.

The energy released in any combustion engine will be the same.*

Period.

* Let's assume for simplicity's sake we have complete combustion.

Interestingly, the HIW site also stated that if the human body could metabolize gasoline, a gallon would provide some 31,000 Calories.   Which brings us to Ian Lane and one of the silliest arguments I've seen made against CICO yet.   His argument boils down to (paraphrasing):  

All matter contains energy therefore food calories are meaningless.  

Now Ian Lane tells us that he is a student of bioorganic chemistry and molecular biophysics.  This makes the articles on his fledgling blog, frankly, quite disturbing.  Instead of talking to Richard Feinman on Facebook, perhaps he should be running some of his ideas past a professor or two at his school so that they can set him straight.  Doing so would certainly save him much embarrassment, though in the LCHF community he'll no doubt be hailed as the next brilliant scientific mind.  Which of course, since he has been discovered by the resident Geology Yalie, Adam "Gatewing" Kosloff, means he'll top the next list of "experts" to confuse you.  (Interestingly, Kosloff has claimed to have majored in physics when his major was Geology and Geophysics, but whatever ;-) ).

As Adam put it in his introductory gushings, Ian is someone who "gets it". He may get *it*, but that "it" sure isn't some pretty basic physical science and chemistry. Adam may also want to check his messages to see if Yale called wanting their degree back, as he repeats the error without a hint of uncertainty about it. I'll quote one paragraph from Ian and in blue include a later paragraph that was quoted by Adam. 

In nutrition, the energy content of foods is sometimes called the “caloric load.” In physics and chemistry, we call the energy content of “stuff” (matter) the specific energy, which can be measured via the heat of combustion.

“One could [not] overconsume the calories in, say, magnesium (which has a specific heat of ~0.243 kcal/kg oC[5]), and then convert this substance into fat and store it in the adipocyte, or oxidize it and create usable ATP. The very idea of it is preposterous…. instead of our focus being on the total concentration of substrates (glucose, free fatty acids and ketone bodies) in vivo, why are we so concerned with the specific heat of these molecules and call them an appropriate surrogate for what might get stored or burned or utilized in some other obscure manner, physiologically? (To me, this just doesn’t make sense. And it drives me insane.)”

As of this writing, that was written by Ian six days ago.  His error regarding specific heat and heat of combustion has been pointed out to him in comments both on Adam's and his own blog, and he has yet to correct this.   To borrow a phrase or two from Adam, this implies that Ian just (a) doesn't know any better, or (b) his brain is not working properly.

The specific heat of a substance is a physical property that dictates how much its temperature will change for a given amount of thermal energy it absorbs (or releases).  In the cgs unit system, this is standardized to water which has a specific heat of 1 cal/g·°C.  The specific heat tells you how many calories are required to raise a gram of something by 1°C.   Perhaps he is confusing this with the definition of a calorie which is defined as the amount of heat energy required to raise one gram of water by one degree Celsius, but these are two different things.  Calories are units of energy, specific heat is a physical material property.  No wonder he's so confused?  This is not a minor difference here, and this is also not an advanced concept.  No chemical reactions going on in heating or cooling a substance.  A hot piece of pure magnesium possesses more thermal energy than a cool piece, but both have essentially the same specific heat over a broad range of temperatures  (assuming no phase transformation).   Specific heat relates the change in temperature to the change in thermal energy.

But let's suppose that Ian is instead talking about the internal energy of matter.  His discussion is still ridiculous.  So you're saying that I can't figure out how much gas to put in my car for a 100 mile trip because I'd need to factor in the chemical energy in snacks I bring with me?  Further if my car gets rained on by magnesium fairy dust I need to factor in all the kinetic energy from these collisions into my equation.  Is Ian eating magnesium for breakfast instead of Wheaties?  That might explain his faulty thinking I suppose!  

Seriously folks, Atwater's calories are not that difficult to understand.  I discussed this at length here, the but here's the Cliffs Notes version.   Food calories were determined for human metabolism of the different macronutrients as measured in a "human calorimeter".  These were averaged and standardized taking various sources, etc. into consideration.  Foods can be analyzed in your usual "bomb calorimeter" for energy content, but this total energy is adjusted per the Atwater factors.    As with my car, what determines the "calories in" is the chemical potential energy of the gasoline molecules.  Whether I drive or weed whack with that energy doesn't change that.

We don't eat magnesium, bark and sand for energy because our bodies do not possess the metabolic pathways to extract chemical energy from them.  Similarly we cannot live and grow on sunlight and CO2 because we lack the photosynthetic pathways that plants do possess to do just that.  And that's also why we don't count sunlight as an energy source, when thinking about our gas powered vehicles.  So please, let's cease with the idiotic and meaningless distractions.   To repeat part of the quotes above:

... instead of our focus being on the total concentration of substrates (glucose, free fatty acids and ketone bodies) in vivo, why are we so concerned with the specific heat of these molecules ...

We are concerned about their chemical potential energy because it is that which powers all of the functions in our bodies.   In a full grown adult, food largely provides the fuel and a few key components to keep our biochemical recycling plant up and running.

We don't give a crap about the specific heat of these molecules, but we do care how much chemical potential energy they provide when metabolized to fuel everything in our bodies.   There is a known hierarchy for the fuel usage which is prioritized not according to the degree of toxicity (as posited by Lane) of the substrate, but rather according to the body's ability to store excesses of that substrate.  We cannot store alcohol so it is metabolized first, next according to Jequier, comes protein.  That which is not immediately needed from the amino acid pool is metabolized, because we do not just build more lean tissue to store protein (we will often gain lean mass along with fat as we gain weight but this is not specifically to store protein).   Then comes the carbs, because glycogen is not very energy dense due to the fact that each gram is associated with 3-4 grams of water.  There are limited stores in animals, because, unlike plants, animals need to be able to move around.  Therefore fat is the preferred storage for fuel in animals due to it's very high energy density.   If you are healthy, you store this fat in the cells designed to deal with it best, the fat cells.  And guess where the fat comes from?  Largely from dietary fat that, again, in healthy humans is rapidly cleared from circulation into the adipocytes.  

Reclaiming the Black Box

The calorie denialists will then fall back to the "what goes on in there is all way too complicated to understand" canard, and this image has become popular of late.  Kosloff is best known for misappropriating the idea of the black box which is used in engineering all the time - especially on systems that are not closed.  When you consume foods, the non-digestable parts comes right back out the other end.  These aren't even technically "in" your body so the black box begins at the lining of the digestive tract and the absorption of usable food molecules.  We absorb simple sugars, amino acids, fatty acids and alcohol, and all of these molecules have chemical potential energy stored in their covalent bonds.  

When we absorb these molecules, we add to the mass and total energy (almost all of the meaningful forms being chemical in nature) of our bodies.  The mass only comes out IFF (that is an acronym engineers should be familiar with, it stands for "if and only if") the molecules that went in have gone through the metabolic pathways to be reacted with oxygen and/or broken down into fairly small molecules that can be excreted through the kidneys or in expired air.  In the normal metabolic state, this consists of carbon dioxide, water and urea, in metabolic starvation some ketones escape, and in diabetes, glucose and/or some protein may pass through the kidneys.   The chemical potential energy of these byproducts of metabolism is significantly less than was put in, and the difference would be energy expended or "lost" in other forms.  I've listed a few in my diagram, everything from breathing and your heart beating to climbing stairs, to nervous system function, making hormones, gluconeogenesis, ... what have you.  It is actually the body's requirement for this "other energy" that largely drives the "mass out".  Mass doesn't get out unless your body needs the energy in the larger molecules so that it breaks them down to get it.  If your body doesn't need the energy what happens to it?  It gets stored.  Stored in the form of chemical potential energy, as glycogen or fat.  Simple.  And 

Mass Stored = Mass In - Mass Out

Energy Stored = Energy In - Energy Out

Folks like Kosloff and Lane are doing their best to confuse what is a simple issue.   That the body may be able to adapt its energy needs or expenditure *to some degree*  has no bearing on the above truths.  Unless you are lifting weights and consuming adequate protein, most of the excess calories you consume will be stored as fat.  As I mentioned before, some lean mass growth will accompany increases in fat mass as organs grow and muscles to support and move about the heavier mass will be needed.   The Bray overfeeding study demonstrated that eating excess protein with excess calories did increase this lean mass growth.  The Horton overfeeding study demonstrated that overfeeding carbohydrate vs. fat on top of the same maintenance diet led to greater fat mass gains in the fat rich diet.  This is because fat is most efficiently stored as fat.  Cue Katie:  Duh.  This is a no brainer, and yet there are supposedly educated people out there who will try to convince you otherwise.

All of Richard Feinman's arguments under the guise of the Second Law are really just First Law arguments.  The energetic cost of certain synthetic pathways, substrate cycling, heat evolution, etc.  All First Law "CO = Calories Out".  It has been shown time and again in metabolic ward studies that the black box all balances out to where energy expenditure over the long term is not influenced much if at all by the macronutrient intake.  If anything, metabolic adaptations favor a high carb low fat diet vs. the opposite when all other things remain equal.   The path that the calories make their way out in no way alters the number of calories in.

Nitpicks on Ian Lane's Article

Calories in micronutrients:

A nutrient could be broadly defined as any substance that is of some benefit (even if excess is detrimental) to our bodies in some sort of "active" way.   I use the term "active" to exclude things like water.  Although it is essential for life, water is not considered a nutrient and its presence is in such excess that it's availability is never factored into biochemical reactions.   It would seem that the distinction between nutrients -- macro v. micro -- can be drawn brightly separating those that contribute energy to the body and those that do not.  Thus vitamins, minerals and various other compounds, that are also present in relatively small amounts, are micronutrients.   Since Ian uses magnesium as his example I will too.

image link

We don't ingest elemental magnesium, and when we ingest one of its various salts, assimilated magnesium exists as a monatomic ionic solute (dissolved Mg++ ions).  There is really nothing that even could be done to get energy from this ion, so this nonsense that there are even calories there is just that ... nonsense.  Further, magnesium is a co-factor for several enzymes in the body.  Its participation is to activate the enzyme and it is not "consumed" in the reaction.  According to Wikipedia, roughly 96% of our body mass is composed of the big four,  O, C, H, and N, and the remaining 4% divvied up between a short list of elements.  Magnesium is among the latter coming in at 0.1%.

Is this guy even serious in bringing up magnesium "calories"?  Seems so, and seems Kosloff is equally seriously convinced this is a good argument. 

Even if here were some caloric value to some of these compounds, the amount ingested is on the order of milligrams to perhaps a gram or two.  Compare this to someone consuming 100 grams each of protein, carb and fat.  But in fact, most of these compounds flow in and out of the body as regulated by your renal system (kidneys) with no requirement to be "burned" in the process -- excess vitamin C comes to mind.  The fact that some fat soluble vitamins can be toxic is evidence that they, too, are not broken down for energy.  

He refers to magnesium as a molecule:

Atoms that are joined by covalent bonds are molecules.  Considering the diversity of such molecules, they are composed of a very small subset of atoms designated as non-metals.  In terms of food, mostly the CHON quartet mentioned earlier.  Magnesium is a metal.  Pure magnesium forms a crystal structure, but as mentioned before, magnesium in the body is in the dissolved ionic form.  I only nit pick this because a bioorganic chemist and molecular biophysicist should pay attention to such details.

He refers to ethanol as a macro-molecule:

Nope.  It's a molecule ... and a rather small one at that (C2H5OH).  Macromolecules are things like large proteins and nucleic acids.   Nothing macro about ethanol, its so boring it only has one possible chemical structure! Ethanol may be considered a "fourth" macronutrient because of its caloric value, but macro in that sense is not the same thing.  I only nit pick this because a bioorganic chemist and molecular biophysicist should pay attention to such details.

No Calorie Receptors:

Firstly, I think Lane might want to check with J. Stanton to see if he considers his notion that we have no calorie receptors to be a copyrighted original thought or not.  It's meaningless of course, but just so he doesn't get accused of plagerism (sic).    I don't even know where to start with this line of reasoning.  Your body will not metabolize these macronutrients to extract their energy is not needed to keep your body up and running.  So if you feed your body too many of these molecules, those that aren't metabolized go into storage.

Your fat cells, however metabolically active they are, are still ultimately your fuel tank.  You fill up the gas tank in your car and it weighs more.  You drive around the block a few times and some of that mass goes out the tail pipe and some of the energy released in the combustion of the gas did the mechanical work of moving your car around.  At the end of the day, unused gas still adds to the weight of your car.  Same with food.  You eat fat and it mostly goes to the fat cells.  If you run around the block a few times, some of that fat gets burned and the mass goes out your wind pipe (expired CO2).  If you don't use all of your "gas" the mass is reflected on the scale.  This is complicated by the other fuels and the limited storage space for them, but in the end, fat is our major energy storage depot, and on any diet that is not extremely low in fat, it is largely the fat that gets left over in the tank at the end of the day.

If you honestly believe your body behaves a whole lot differently from a black box perspective, I'm going to suggest that you've chosen the wrong discipline.

You Can't Get Fat From Booze?

So after all the magnesium mumbo jumbo, Ian turns his argument to one of explaining why a calorie-containing substance can't make you fat.  I'm going to presume he's never lived in a dorm and observed his fellow students during their freshman year.  Because it's not called a "beer belly" for nothing, and a goodly portion of skinny-to-chubby to begin with students will fatten because they've added alcohol and accompanying calories to their diet without compensating by eating less.  Or look around the fitness communities -- paleo and low carb being no exception.  Weight loss diets almost all cut out unnecessary calories first and that means alcohol.  Well, except for Banting ...  but you'll note he reduced his alcohol consumption as well as his food intake (carbs and fat and just all around).

Someone pointed out in comments that alcoholism is often accompanied by weight loss.  Tis true.  Some alcoholics generally lose interest in food and it is impossible to sustain a human body on alcohol alone (much like protein cannot provide sufficient calories, e.g. "rabbit starvation") .    But of course alcohol can be fattening!  

Throwing in Random "Facts":

Just two of several instances I thought I'd mention:

Interestingly, obese persons tend to have very poor micronutrient statuses, on average, which is pretty consistent across the board.[1-4]

This came after the discussion of how presposterous it would be to count the caloric load of micronutrients, but the micronutrient status of the obese would be irrelevant to any argument he's making here.  Then we have:

(Oh yeah, did I mention that glucose is toxic to human cells?[15] Open any biochemistry textbook ever written to confirm this. Or, just ask your local diabetologist what happens when our cells aren’t constantly oxidizing our extracellular fluid glucose, and it rises above ~120 mg/dL for any length of time…)

I'm not sure that "toxicity" of chronic hyperglycemia can be reduced to "glucose is toxic to human cells" any more than the concept of lipotoxicity (tons of papers on that Ian) can be extended to say that "fatty acids are toxic to human cells".  Context is everything and Ian says he's a stickler for details.   It is also important to point out that hyperglycemia is an end-stage symptom in classic Type 2 diabetes, and thus is always accompanied by dysregulated fatty acid metabolism and relative insulin insufficiency.  Thus the more "severe" toxicity attributed to the glucose may be due to more than the glucose itself as well as interactions between the various agents.  

There are many other facts and such he throws in here and there.  Heck, I'm probably not one to talk about keeping things concise and on central point, but ...  In the first case, he just randomly brings up micronutrient deficiencies in obesity.  I suppose he's trying to state that if micronutrient calories counted you wouldn't have deficiencies?  Or perhaps it was to pad the reference count.  But speaking of the reference count, in my second example he makes a rather sweeping statement backed up by a single reference, followed by (paraphrase) "don't believe me or my reference, crack a textbook open or engage your local diabetes doc".  Sorry, that doesn't cut it, especially given that just a few short paragraphs earlier Lane had bragged on liking to cite his sources.   Here is a short excerpt from his source (I like to cite and link to mine when available):

In type II (non-insulin-dependent) diabetes in humans, a considerable body of evidence has accumulated indicating that a chronic physiological increment in the plasma glucose concentration leads to progressive impairment in insulin secretion and may contribute to insulin resistance as well. The precise biochemical mechanism(s) responsible for the hyperglycemia-induced defect in insulin secretion remains to be defined but may be related to a defect in phosphoinositide metabolism.

The full text is not available for free.  It's long and I haven't had a chance to read it thoroughly, but the focus is on beta-cell "toxicity" and how hyperglycemia can further impair insulin secretion thus exacerbating the insulin deficiency that is at the route of the hyperglycemia in the first place.     I'm not quite sure where the 120 mg/dL comes from ...  If you're going to write a blog post with 28 references, you really owe it to your readers to do better than that with the referencing of such sweeping statements as this.  Especially when you are trying to sound like your statement is uncontroversial and backed by copious evidence.  Cite it!  Specifically.

In Conclusion ...

There are all manner of sayings that point out that desperation tends to escalate right before the fall.  Perhaps this ever more frantic grasping at smaller and smaller straws is a sign that the end of these absurd arguments is near.  One can only hope.  I for one am tired of the ever more ridiculous explanations while ignoring the obvious.  As a population, on average:

• We are eating more
• We may be moving less
• We weigh more and have more fat mass

It's pretty safe to say that we did not en mass develop neuro-endocrinological horizontal growth disorders of the adipocytes.   Fat accumulates when you put more fuel in the tank than you need.   This is not dysregulated metabolism.  It is how things are supposed to work.

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Ian put forth an interesting argument about ethanol and body fat accumulation.  Kinda (accidentally I presume) puts a serious dent in, if not demolishes the whole carbs are fattening hypotheses.  For another day ... I still owe a pastafarian a blog post.