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  • dinesh75
    started a topic Trying to understand carbs -> glycogen -> fat

    Trying to understand carbs -> glycogen -> fat

    hey guys, I am trying to wrap my head around ingestion of carbs, insulin response, glycogen storage, and then fat storage.

    How does the glycemic index play in all of this? How is this cycle different if the GI is low vs when GI is high?

    Thanks.

  • John Caton
    replied
    Originally posted by Elliot View Post
    Energy is produced outside of the mitochondria. If you say "fat has more than 2.25 times as much energy," and not "fat has more than 2.25 times as much energy produced in the mitochondria," you would need to account for glycolysis. But the larger point is that your calculations were for ATP, which is only one form of energy. If you really want to show that fat actually produces more than 2.25 times as much energy, and not ATP specifically, you would also need to account for all forms of energy, including heat. Or, if you only want to talk about ATP, then you need to talk about how much ATP is produced, because it's not necessarily the maximal amount. Free fatty acid promote uncoupling, which would directly inhibit ATP production on a high-fat diet.
    You seem to downplay the fact that ATP, while releasing only one form of energy, is our primary source of electrical energy to power our bodies. I'm not even trying to account for all forms of energy. My brain doesn't have enough ATP to power that task.

    Glycolysis is still an intracellular function to prepare glucose for ATP production in the mitochondria and it produces some ATP in the process prior to the mitochondria, while also consuming some ATP to power the process. Before you even say it, I know that the Fatty Acid Spiral also consumes some ATP. Body processes require energy. The question is, which process nets the greatest ATP output. Whether you measure the output expressed per molecule, mole or gram, what does it matter (pun intended)? Fat still wins.

    Heat is an important form of energy, of course. I dare say it isn't the most important source of energy to drive life, however. Heat is required to create a conducive environment for enzymatic and hormonal actions and that varies with lifeforms. Heat isn't what directly powers our brain, heart, other muscles, nerves or enzymatic and hormonal actions. It just renders an ideal environment for the actions.

    Although I wasn't trying to account for heat, it deepens my wonderment at why we stay in the dark ages trying to account for electrical output using a unit of potential heat measurement. I'm sure there are minds that can calculate electrical energy potential in the various macros. Why don't they come forward? Why don't we see that on nutritional labels? In the meantime, the net numerical ATP output (in molecules) available to the cell, is all I need to guide my food choices.

    I apologize for misspelling your name in a prior post, but you got me back in a humorous way. My cat is named Elliott. Not that I confused the two of you, but my cranial autocorrect is to blame. Peace.
    Last edited by John Caton; 08-22-2015, 04:40 AM.

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  • John Caton
    replied
    Originally posted by Gorbag View Post
    I would go very careful with bulletproof coffee if that was the case...
    Gee whiz, I wish I had read this before consuming those 300 "calories" of fat in my bulletproof coffee this morning. Dang it.

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  • Gorbag
    replied
    Originally posted by John Caton View Post
    So, for all those who insist on calorie counting, you had better calculate those fat calories in your steak as closer to 18 than 9.
    I would go very careful with bulletproof coffee if that was the case...

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  • Elliot
    replied
    Originally posted by John Caton View Post
    Calorie comparisons may be true in calorimeters but not in mitochondria.
    Energy is produced outside of the mitochondria. If you say "fat has more than 2.25 times as much energy," and not "fat has more than 2.25 times as much energy produced in the mitochondria," you would need to account for glycolysis. But the larger point is that your calculations were for ATP, which is only one form of energy. If you really want to show that fat actually produces more than 2.25 times as much energy, and not ATP specifically, you would also need to account for all forms of energy, including heat. Or, if you only want to talk about ATP, then you need to talk about how much ATP is produced, because it's not necessarily the maximal amount. Free fatty acid promote uncoupling, which would directly inhibit ATP production on a high-fat diet.

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  • John Caton
    replied
    No, EllioT. Not all fats provide 2.25X the energy in mass as glucose. My whole point in the thread is to knock that belief down. In the case of Stearic Acid, the second most abundant saturated fat, almost 4X more energy per gram is supplied over glucose.

    Calorie comparisons may be true in calorimeters but not in mitochondria.

    I understand it appeared in one of my posts that I agreed there was 2X (actually 2.25) advantage of fat over glucose, but I've had enough posts on here and you and I have debated this enough that my tongue-in-cheek statement should have shown through. I guess it didn't with you. So, for all those who insist on calorie counting, you had better calculate those fat calories in your steak as closer to 18 than 9.

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  • Elliot
    replied
    Originally posted by John Caton View Post
    The quote you cite doesn't mention units at all so why do you say I changed units again?
    You said "increased energy." Not "increased energy per mass," or "increased energy per molecule," or "increased energy per mole." Just "increased energy." However, if you truly meant "increased energy per mass," or "increased energy per mole," then I still don't see why it's beneficial to get more energy per mass or more energy per mole. If one were to produce the same amount of energy, burning more carbs to compensate for the difference in energy per mass, what is the drawback?
    Originally posted by John Caton
    Switching from molecules to moles to grams is not a switch from the consideration of the differences in mass. It was just a restatement of mass units since you were so quick to point out that fat molecules are larger than glucose molecules. That was a valid observation you made so I provided some equalization to express both in grams. I previously tried to equalize the comparison using moles. Both of those switches were intended to provide clarity and to reaffirm the advantage fat has over glucose in output of energy to fuel your body. Your continued argument about "switching units" is a contrarian one.
    It's not contrarian for the sake of being contrarian. The original statement to which I responded here compared numbers using different units, as if they were the same. Here is the statement that started this:
    Originally posted by John Caton
    based on your calorie based assumptions, fat should only deliver 2X the energy as carbs...but when at its full potential, driven by proper hormonal signals, high saturated fat will deliver 6X the energy of glucose, not the 2X you'd expect from its calorie count.
    You use quantities with different units in the same sentence and compare them as if they are comparable. Fat does, in fact, provide 2X (more like 2.25X) the energy of carbs, per mass. It provides about 6X the energy of glucose, per molecule (assuming we're counting ATP produced in the mitochondria and the fatty acid is about 17 carbons). So the bolded portion you said is false is actually true. It is not contradicted by the underlined portion, because they are measuring different quantities with different units. You said one statement is false and one is true, but they are both true!
    Last edited by Elliot; 08-21-2015, 07:12 AM.

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  • John Caton
    replied
    Originally posted by Elliot View Post
    Johnn, you've changed units again. You've been doing this frequently throughout this thread. Fat has more energy per mass than glucose, and it has more energy per molecule. Neither of these is total energy. To get from energy per mass to total energy, you would need to know the total amount of mass being burned.

    As I said before, to get an equal amount of energy from carbs, you could simply burn more of them.

    Total energy is neither energy per mass nor energy per molecule!
    The quote you cite doesn't mention units at all so why do you say I changed units again?

    Switching from molecules to moles to grams is not a switch from the consideration of the differences in mass. It was just a restatement of mass units since you were so quick to point out that fat molecules are larger than glucose molecules. That was a valid observation you made so I provided some equalization to express both in grams. I previously tried to equalize the comparison using moles. Both of those switches were intended to provide clarity and to reaffirm the advantage fat has over glucose in output of energy to fuel your body. Your continued argument about "switching units" is a contrarian one.

    As I'm sure you know "Total Energy" has a specific meaning and our bodies do not utilize the "Total Energy" of glucose nor fat, nor anything else for that matter. If you did, I doubt you'd live to talk about it. That being said, the Total Energy of fat would probably kill you faster. Higher mass = higher energy.
    Last edited by John Caton; 08-21-2015, 02:51 AM.

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  • Elliot
    replied
    Originally posted by John Caton View Post
    Benefits? Gee, Elliott, that's a tough one.

    Aside from increased energy to power your brain, contract your muscles, pump your heart and synthesize your RNA/DNA, I can't think of one.
    Johnn, you've changed units again. You've been doing this frequently throughout this thread. Fat has more energy per mass than glucose, and it has more energy per molecule. Neither of these is total energy. To get from energy per mass to total energy, you would need to know the total amount of mass being burned.

    As I said before, to get an equal amount of energy from carbs, you could simply burn more of them.

    Total energy is neither energy per mass nor energy per molecule!
    Last edited by Elliot; 08-20-2015, 07:30 PM.

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  • whitebear
    replied
    The carb battle is humorous. Both w.o.e. work depending on the individual. I might be biased but there seems to be more evidence and n=1 in favor of low carb. As someone who puts hunting/gathering into practice animal food gets you a lot more bang for your buck. You have to spend days gathering enough veggies/tubers to nourish your family but it can take only a few hours to harvest weeks of food from a single kill.

    Sent from my SM-N910V using Tapatalk

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  • John Caton
    replied
    Benefits? Gee, Elliott, that's a tough one.

    Aside from increased energy to power your brain, contract your muscles, pump your heart and synthesize your RNA/DNA, I can't think of one.

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  • Elliot
    replied
    Originally posted by John Caton View Post
    That is beneficial, is it not?
    I don't see why it would be.
    Originally posted by John Caton
    I say it is more efficient, despite that being a relative term, in the same sense that it is more efficient to carry 40,000 lbs in a truck, rather than carrying 1,000 pounds in the trunk of 40 cars.
    I don't see how the analogy applies here. Really, how is it beneficial to get more energy per molecule? Don't use an analogy; give me an actual, direct explanation of the benefit.
    Originally posted by John Caton
    I'm getting long winded. Sorry.

    Elliott is correct. One can easily offset the available energy derived from fats by just eating more carbs. If you time the intake and energy expenditure correctly, you won't gain weight from fat storage. If you don't time it right, you will pack on fat.
    And your solution is to eat fat, instead? Every time you eat fat, you pack on fat. You might burn it later, but it does not all get burned immediately. It sounds like your solution to avoid possibly converting glucose into fat is...to eat fat, which is already fat. No conversion necessary.
    Originally posted by John Caton
    On the other hand, you can be a predominant fat burner by assuming food will remain abundant and glean much more available energy for life processes and worry less about fat storage and weight gain. Put it in and burn it off. That's efficiency.

    Finally, for Elliott and Artbuc, if you don't want to consider the 6X advantage at the molecular level, look at it gram to gram.

    If Y represents the number of molecules per gram, 1Y represents Stearic Acid molecules per gram. Therefore, glucose has 1.576Y molecules per gram.

    If Z represents the energy in ATP output per molecule, then 1Z represents the energy output of glucose and the output of Stearic Acid is 6Z. Y * Z = energy/gram. Glucose energy per gram is 1.576YZ. Stearic Acid fat energy per gram is 6YZ. Gram for gram, fat yields 3.81 X more energy. And this is in addition to heat energy fat produces without ATP.
    You mention this without mentioning the heat energy glucose produces.
    Originally posted by John Caton
    Kinda deflates the 2.25X difference that calorie counters assume.
    No, because you're talking about ATP, and they're talking about total energy.

    Please explain why getting more ATP per molecule or per mass is beneficial. Please do not provide an analogy; I want a direct explanation of benefit.
    Last edited by Elliot; 08-20-2015, 10:17 AM.

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  • Gorbag
    replied
    Originally posted by John Caton View Post

    If Y represents the number of molecules per gram, 1Y represents Stearic Acid molecules per gram. Therefore, glucose has 1.576Y molecules per gram.

    If Z represents the energy in ATP output per molecule, then 1Z represents the energy output of glucose and the output of Stearic Acid is 6Z.

    Y * Z = energy/gram. Glucose energy per gram is 1.576YZ. Stearic Acid fat energy per gram is 6YZ. Gram for gram, fat yields 3.81 X more energy. And this is in addition to heat energy fat produces without ATP. Kinda deflates the 2.25X difference that calorie counters assume.
    Hooraay! Congratulations John, you have by this masterpiece of a thread proved that the entire community of scientist all over the world have all been completly wrong on this subject! Now prepeare yourself to be a Nobel laurate and to eat paleo food at the kings table in Stockholm Sweden...

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  • NewOldGuy
    replied
    With respect, I don't believe the efficiency or relative energy difference is particularly useful to dietary goals, since we can simply eat as much saturated fat or as much carbohydrate as we want. But there can be significant differences in outcomes related to diets using different mixes of the two, regardless of calories. And there are significant differences related to the food "carriers" that bring those in to the body as well, particularly in relation to glucose-containing foods and how they are processed in the body. Using highly refined carb sources is bad for everyone, period.
    Last edited by NewOldGuy; 08-20-2015, 06:43 AM.

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  • John Caton
    replied
    Originally posted by Man View Post
    It boggles the mind that some people implicitly think that the body prefers a fuel type more than another one. makes absolutely no sense. While all this discussion about energy yield per molecule or mass is interesting (in an academic sense), it does not change how metabolism works:

    - in the absence of a ready-to-be-burnt fuel other than fat, the body will use fat from reserves
    - if any fuel type other than fat is present, the body will burn that
    - this is not black and white, it has to do with average because while fat burning is blunted in the presence of carbs, it is not stopped. And vice-versa: you still use glucose in the fasting state (brain) while most of the body will use fat (muscles, etc) in the context of glycogen depletion.
    Perhaps, it boggles your mind?

    Really, none of us are making totally inaccurate statements. We're just emphasizing different pieces of a bigger picture that truly should boggle the mind.

    Actually, when glucose is available, the body will preferentially use it first and store fat for times when food may not be so abundant. But, the utilization of glucose for energy is limited by the GLUT4 shuttle and insulin to trigger GLUT4 transport. Then, in the cell some of glucose's carbon is utilized to produce CO2 and not to energy. Therefore, energy output is limited and more has to be consumed to offset the loss. Again, this is not a problem because it is assumed that more and more glucose is available in this scenario. In the same scenario, if we are putting glucose in faster than the cells can take it up, the body will opt to store it as glycogen for short term access and fat for longer term access. Now, if we can sync our consumption of glucose producing carbs to our activities to avoid long term storage of fat, or if we raise our activity levels to keep glycogen stores in a deficient state, then fat gain doesn't happen. That's fine, if you can do it.

    Back to the mass-to-energy debate. There really is no debate here because we aren't dealing with Total energy anyway. These aren't nuclear reactions. We aren't making complete mass-to-energy conversions with fats or carbs. Since we aren't, then the debate has to be about how much of the available energy is gleaned from the simple chemical reactions within the cell. Mass differences would only be important if both macros underwent identical chemical reactions. Eventually, they do; when both reach the acetyl CoA stage. But, leading up to that point, beta oxidation of fatty acids yields additional available energy that glucose does not. Greater mass is the explanation here, but only when considering the relative difference between different fatty acids, not the difference with glucose. The more carbon in the fatty acid, the more times the fatty acid has to be chemically cycled in the Fatty Acid Spiral, specific to fats. The more cycles, the more energy gleaned. That is beneficial, is it not? I say it is more efficient, despite that being a relative term, in the same sense that it is more efficient to carry 40,000 lbs in a truck, rather than carrying 1,000 pounds in the trunk of 40 cars. How's that for mixing units, Elliott?

    I'm getting long winded. Sorry.

    Elliott is correct. One can easily offset the available energy derived from fats by just eating more carbs. If you time the intake and energy expenditure correctly, you won't gain weight from fat storage. If you don't time it right, you will pack on fat.

    On the other hand, you can be a predominant fat burner by assuming food will remain abundant and glean much more available energy for life processes and worry less about fat storage and weight gain. Put it in and burn it off. That's efficiency.

    Finally, for Elliott and Artbuc, if you don't want to consider the 6X advantage at the molecular level, look at it gram to gram.

    If Y represents the number of molecules per gram, 1Y represents Stearic Acid molecules per gram. Therefore, glucose has 1.576Y molecules per gram.

    If Z represents the energy in ATP output per molecule, then 1Z represents the energy output of glucose and the output of Stearic Acid is 6Z.

    Y * Z = energy/gram. Glucose energy per gram is 1.576YZ. Stearic Acid fat energy per gram is 6YZ. Gram for gram, fat yields 3.81 X more energy. And this is in addition to heat energy fat produces without ATP. Kinda deflates the 2.25X difference that calorie counters assume.
    Last edited by John Caton; 08-20-2015, 05:08 AM.

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