In the study you cite about energy transfer from fat (https://pubmed.ncbi.nlm.nih.gov/15615615/), the data analyzed comes from Ancel Keys' 1950 Starvation study, where participants were fed approx. 1567kcal (6.56MJ/d), the measured outcome was that approx 290kJ/Kg/d (69.3kcal/Kg/d) is the "maximum possible fat oxidation rate", however, isn't that just the body lowering it's metabolism, and compensating with the few FFA it can extract from the fat cells? While I can't find exact figures on this experiment, a quick google search tells me "the starvation diet reflecting that experienced in the war-torn areas of Europe, i.e., potatoes, turnips, rutabagas, dark bread, and macaroni." (https://jn.nutrition.org/article/S0022-3166(22)10249-X/fulltext), so wouldn't the high insulin prevent Hormone-Sensitive Lipase from breaking down stored FFA? (Note that this last link contradicts the study, as it says they were fed 1800kcal)
Just as a note, the part where this study is cited probably could use a bit of disambiguation, as that study is not related to water fasting, but a severely hypo-caloric diet.
At best, this study shows the maximum fat oxidation rate when you're in a major calorie deficit, and mostly eating carbs.
However, in the study linked below, fat adapted athletes burned between 1.3 to 2 grams of fat per minute, which (while an exaggeration) would be approx. 78 to 120 grams per hour, or approx. 708 - 1080 kcal per hour, clearly beyond what the previous study claims. Now, sure, they probably have a decent amount of this fat as Chylomicrons floating around, but they ran for 25 Km total in their longest run, even Eulid Kipchoge can't do that within an hour. (https://pubmed.ncbi.nlm.nih.gov/32358802/#&gid=article-figures&pid=figure-2-uid-1)
So burning 2800kcal per day from body fat (like you say on your figure, "lol ya right") does not sound impossible, Extended fasting does lower BMR, however I don't think it's so black and white.
Oh interesting, I hadn't realized that's where the data came from.
I'm actually pretty familiar with that experiment, there's a great video on Youtube by one of the participants (who's very old now lol). Search for "Minnesota stavation experiment" or similar.
It was quite complicated because it lasted nearly a year and they changed a lot of variables. For one, there were several groups that were getting reduced calories at different rates. Plus, their caloric intake was proportional to their lean body mass, so everyone got a different total amount.
But yes, it makes you wonder if these "maximum flux rates" are in any way influenced by the rather abnormal circumstances of the starving participants.
You're right that it's clearly way more complicated than the "bucket of body fat" theory, e.g. many people can't seem to access their body fat well. Insulin definitely plays a role, and probably other factors.
I wish they'd to experiments like this these days lol :)
"Eating less will cause weight loss (not if ΔCI < ΔCO)"
Delta values are absolute, so they can denote change in both directions: a small decrease in CI and a large increase in CO can be described as ΔCI < ΔCO, while causing weightloss. You probably meant small decrease CI + large decrease CO and then this is true for gaining weight, but better to write that down as CI > CO! (or specify that you mean decreasing deltas for both)
> Saying “somebody lost fat” is literally saying that calories left his body
Even that does not follow. You still give too much credit to CICO. Calories is a measure of energy. Fat mass is measured in kilograms (or pounds). There is no law of physics or thermodynamics linking the two. It is a contingent fact of biology that (most?) animals store most of their energy in the form of fat.
And in the (very) short term, it’s wrong. When you spend energy, it involves (for example) breaking ATP into ADP + Pi. Note that while ATP -> ADP + Pi changes the energy content in your body (you do CO, you lose calories), you lose exactly 0 gram in the process ; not a single molecule of fat (or any of its constituent atom) has left your body in that exothermic reaction.
I think it's not a law of physics, it's a law of accounting. There exist of course no physical "calories" in substrates. It's a unit we ascribe to the potential chemical energy held in the substrate. A calorie is thus an abstract measurement.
It's kind of like if you pay me in cows or grain, it's not literal "dollars" but we kinda know the rough market price and we can say "that's $1000 worth of grains."
If you were to count up all the energy substrates in your body at any given time, and then ascribe the 4/4/9 to each gram of mass you counted, you would come up with a number. That's the number CICO measures.
The ATP thing is "only" because our measure of CICO is necessarily imprecise and misses a lot of things. E.g. there are many things in the body that are energy substrates, but that we can't simply use for energy. Or not at all times. E.g. is your body going to use all the fat in your brain for energy? Probably not (I think), maybe it can if you're starving to death, but I'm not even sure of that. Likewise, most lean tissue isn't burned for energy unless absolutely necessary.
But like you say, fat makes up 98% or so of the potential chemical energy in the body, and it's usually what we want to lose, so we gloss over the details.
Vitruvius normally has one side of his face as partial profile, matching the angle of his turned feet… 45 degrees perhaps. That is why one eye looks wonky.
Reading over this whole thing, and your interview with the time mold guy, it sounds like you have an impaired GI tract as a lifelong situation. If this is the case, a GI fecal implant might help. And, if this is the case, using you as my fat loss guru would be a terrible idea :)
What makes you think it's a GI tract issue? I generally don't do super well with very high fiber. But would that last a lifetime if it's a microbiome thing? Normal amounts of green veggies are OK, but the potato diet didn't sit well with me.
I guess I interpreted the emphasis you put on various things. It's not like I'm a doctor. The Circadian rhythm thing is fascinating, and I'm sure that researchers would care about a report curing the disorder with diet.
Potatoes are really interesting- the skins are loaded with alkaloids. The potato diet with skins on apparently hits some people with too much alkaloid. Potatoes used to be so poisonous that 2000/3000 years ago the Andean Indians ate them with clay to soak up the poisons. Thank them for breeding down the alkaloids to a pleasant level.
You're right about heavy whipping cream. That stuff really does throw a very big satiety switch very hard.
"I’ve stayed weight-stable for 2 months straight eating 1,000kcal/day"
ORLY?
Would you be confident to go into a metabolic ward where there is a team actually holding your calorie intake at 1,000kcal/day and see if this holds true? If what you are actually saying is true it would upend huge swaths of scientific literature. Scientists would be fascinated to discover and study your unique metabolic state.
Or maybe you were eating more than 1,000kcal/day...
In the study you cite about energy transfer from fat (https://pubmed.ncbi.nlm.nih.gov/15615615/), the data analyzed comes from Ancel Keys' 1950 Starvation study, where participants were fed approx. 1567kcal (6.56MJ/d), the measured outcome was that approx 290kJ/Kg/d (69.3kcal/Kg/d) is the "maximum possible fat oxidation rate", however, isn't that just the body lowering it's metabolism, and compensating with the few FFA it can extract from the fat cells? While I can't find exact figures on this experiment, a quick google search tells me "the starvation diet reflecting that experienced in the war-torn areas of Europe, i.e., potatoes, turnips, rutabagas, dark bread, and macaroni." (https://jn.nutrition.org/article/S0022-3166(22)10249-X/fulltext), so wouldn't the high insulin prevent Hormone-Sensitive Lipase from breaking down stored FFA? (Note that this last link contradicts the study, as it says they were fed 1800kcal)
Just as a note, the part where this study is cited probably could use a bit of disambiguation, as that study is not related to water fasting, but a severely hypo-caloric diet.
At best, this study shows the maximum fat oxidation rate when you're in a major calorie deficit, and mostly eating carbs.
However, in the study linked below, fat adapted athletes burned between 1.3 to 2 grams of fat per minute, which (while an exaggeration) would be approx. 78 to 120 grams per hour, or approx. 708 - 1080 kcal per hour, clearly beyond what the previous study claims. Now, sure, they probably have a decent amount of this fat as Chylomicrons floating around, but they ran for 25 Km total in their longest run, even Eulid Kipchoge can't do that within an hour. (https://pubmed.ncbi.nlm.nih.gov/32358802/#&gid=article-figures&pid=figure-2-uid-1)
So burning 2800kcal per day from body fat (like you say on your figure, "lol ya right") does not sound impossible, Extended fasting does lower BMR, however I don't think it's so black and white.
Oh interesting, I hadn't realized that's where the data came from.
I'm actually pretty familiar with that experiment, there's a great video on Youtube by one of the participants (who's very old now lol). Search for "Minnesota stavation experiment" or similar.
It was quite complicated because it lasted nearly a year and they changed a lot of variables. For one, there were several groups that were getting reduced calories at different rates. Plus, their caloric intake was proportional to their lean body mass, so everyone got a different total amount.
But yes, it makes you wonder if these "maximum flux rates" are in any way influenced by the rather abnormal circumstances of the starving participants.
You're right that it's clearly way more complicated than the "bucket of body fat" theory, e.g. many people can't seem to access their body fat well. Insulin definitely plays a role, and probably other factors.
I wish they'd to experiments like this these days lol :)
"Eating less will cause weight loss (not if ΔCI < ΔCO)"
Delta values are absolute, so they can denote change in both directions: a small decrease in CI and a large increase in CO can be described as ΔCI < ΔCO, while causing weightloss. You probably meant small decrease CI + large decrease CO and then this is true for gaining weight, but better to write that down as CI > CO! (or specify that you mean decreasing deltas for both)
Ha, you're right I forgot about that :)
But wait, isn't it ok since I'm implying which direction (+/-) I'm referring to with "Eating less" and "Eating more" at the beginning of the sentence?
Great explanation of internal versus external calorie deficit though. Very interesting concept!
> Saying “somebody lost fat” is literally saying that calories left his body
Even that does not follow. You still give too much credit to CICO. Calories is a measure of energy. Fat mass is measured in kilograms (or pounds). There is no law of physics or thermodynamics linking the two. It is a contingent fact of biology that (most?) animals store most of their energy in the form of fat.
And in the (very) short term, it’s wrong. When you spend energy, it involves (for example) breaking ATP into ADP + Pi. Note that while ATP -> ADP + Pi changes the energy content in your body (you do CO, you lose calories), you lose exactly 0 gram in the process ; not a single molecule of fat (or any of its constituent atom) has left your body in that exothermic reaction.
I think it's not a law of physics, it's a law of accounting. There exist of course no physical "calories" in substrates. It's a unit we ascribe to the potential chemical energy held in the substrate. A calorie is thus an abstract measurement.
It's kind of like if you pay me in cows or grain, it's not literal "dollars" but we kinda know the rough market price and we can say "that's $1000 worth of grains."
If you were to count up all the energy substrates in your body at any given time, and then ascribe the 4/4/9 to each gram of mass you counted, you would come up with a number. That's the number CICO measures.
The ATP thing is "only" because our measure of CICO is necessarily imprecise and misses a lot of things. E.g. there are many things in the body that are energy substrates, but that we can't simply use for energy. Or not at all times. E.g. is your body going to use all the fat in your brain for energy? Probably not (I think), maybe it can if you're starving to death, but I'm not even sure of that. Likewise, most lean tissue isn't burned for energy unless absolutely necessary.
But like you say, fat makes up 98% or so of the potential chemical energy in the body, and it's usually what we want to lose, so we gloss over the details.
Thanks for taking your wrecking ball to CICO! Now I can just point to this post rather than laboriously assembling mine.
Ha, thanks ;)
Vitruvius normally has one side of his face as partial profile, matching the angle of his turned feet… 45 degrees perhaps. That is why one eye looks wonky.
Reading over this whole thing, and your interview with the time mold guy, it sounds like you have an impaired GI tract as a lifelong situation. If this is the case, a GI fecal implant might help. And, if this is the case, using you as my fat loss guru would be a terrible idea :)
Hey :)
What makes you think it's a GI tract issue? I generally don't do super well with very high fiber. But would that last a lifetime if it's a microbiome thing? Normal amounts of green veggies are OK, but the potato diet didn't sit well with me.
I guess I interpreted the emphasis you put on various things. It's not like I'm a doctor. The Circadian rhythm thing is fascinating, and I'm sure that researchers would care about a report curing the disorder with diet.
Potatoes are really interesting- the skins are loaded with alkaloids. The potato diet with skins on apparently hits some people with too much alkaloid. Potatoes used to be so poisonous that 2000/3000 years ago the Andean Indians ate them with clay to soak up the poisons. Thank them for breeding down the alkaloids to a pleasant level.
You're right about heavy whipping cream. That stuff really does throw a very big satiety switch very hard.
Yea, I suspected the skins as well, and went to peeled potatoes after a week or so. But that might've been too late.
"I’ve stayed weight-stable for 2 months straight eating 1,000kcal/day"
ORLY?
Would you be confident to go into a metabolic ward where there is a team actually holding your calorie intake at 1,000kcal/day and see if this holds true? If what you are actually saying is true it would upend huge swaths of scientific literature. Scientists would be fascinated to discover and study your unique metabolic state.
Or maybe you were eating more than 1,000kcal/day...
Huh? Pretty consistent with the scientific literature that people's metabolism can turn down dramatically. Nothing special there.
I ate the exact same meal, weighed with a kitchen scale, every day. As my only meal. So yea, pretty confident.