Random Questions, Sort Of About Glycogen

[Bill Been]

Jordan,
I've had a few random thoughts and questions rattling around in my noggin. I know you could help provided I can formulate this into something cogent.

The Big Picture is me trying to get my head around the interplay of glycogen, ketosis, strength training nutrition, and insulin sensitivity.
- The LCHF/ketotic eaters (which I used to be) have "drone zone" energy for days. I could go for very long periods on very little food with no reduction in my ability to produce the modest levels of force needed for my life, including kettlebell training. I never did any of the peri-training carb intake for glycogen replenishment;
- Most of the ketotic eaters who also engage in physical training seem to mostly be involved in endurance type activities where they find ketosis to be exceptionally glycogen-sparing (per Peter Attia);

How much carb does it take to replenish glycogen?
Does muscle glycogen refilling take precedence over other uses for carb?
How fully depleted is glycogen after a heavy SS session?
Do heavy grinds like 5RM deads deplete glycogen as extensively as Type 2b dependent drills like cleans, push-presses and jerks?
If ketotic, how is glycogen replenished
Once replenished, does glycogen "stay put" until your next glycolytic training event, or does it "leak down"?
Does subsequent food intake replenish glycogen in an on-going process?
For some of our "fluffier" Bros who may be tippy-toeing up on the metabolic syndrome, do we have a feel for how quickly heavy barbell training begins to restore insulin sensitivity and thereby better nutrient partitioning? It seems to me that until that happens, energy will still be very low and the body will continue to prioritize glycogen storage in adipose tissue instead of muscle.
How much bigger "reservoir" of glycogen storage opens up when insulin sensitivity is restored? It seems to my amateur eye that this is a pretty Big Deal, taking a trainee from being unable to do anything with carb but store it as fat to the ability to process it normally.
I remember that carb has a role in MPS, but can't remember the layman's take on that one.

[Jordan Feigenbaum]

Good questions, Bill. Answers inline:

How much carb does it take to replenish glycogen?

It depends how much has been depletes if you're looking for it to be replenished in <20-24hrs. At that point (about a day) most muscle glycogen can be refilled without any carbohydrates unless there has been an exhaustive workout or total cals are very low.

Does muscle glycogen refilling take precedence over other uses for carb?

Depends really. Big picture, however, is that if you have depleted muscle glycogen and significant amounts of liver glycogen stores- you're going to replenish the liver's stores first (60-100g total) and then the muscles (~350g total) while maintaining blood sugar and sugar supply to the brain via ingesting carbs, creating new sugar (gluconeogensis), or releasing stored sugar from the liver (glycogenolysis).

How fully depleted is glycogen after a heavy SS session?

Eh, the volume isn't TERRIBLY high but then the relative intensity is pretty high and depending on who you read, glucose can be oxidized at the level of the muscle at a rate of about 200kCal/kg/min of activity. Let's say a person on LP does 3 sets of 5 squats, benches, and 1x5 of deadlifts and that in addition to this- his/her last warm ups also are relatively intense. So I'm not sure how many total "minutes" of intense exercise, but we'd expect a really big decrease in intramuscular glycogen, right? WRONG. Most evidence suggests intramuscular glycogen levels "only" fall by about 30% post exhaustive exercise as measured by biopsy. For instance, one of classic studies had folks do front squats, back squats, leg press, and leg extensions x 5 sets each and muscle glycogen levels only fell by 26%.

Do heavy grinds like 5RM deads deplete glycogen as extensively as Type 2b dependent drills like cleans, push-presses and jerks?

Probably about the same, to be honest, unless the volume is extremely different.

If ketotic, how is glycogen replenished

Gluconeogensis will help make glucose that will get stored in the muscle after the liver is mostly full.

Once replenished, does glycogen "stay put" until your next glycolytic training event, or does it "leak down"?

Muscle glycogen does not contribute to blood sugar levels, but low levels of muscle glycogen are constantly turning over as you're active- even at relatively low intensities. That said, energy from lipid oxidation is allowed to contribute to a higher level at lower intensities.

Does subsequent food intake replenish glycogen in an on-going process?

Yes.

For some of our "fluffier" Bros who may be tippy-toeing up on the metabolic syndrome, do we have a feel for how quickly heavy barbell training begins to restore insulin sensitivity and thereby better nutrient partitioning? It seems to me that until that happens, energy will still be very low and the body will continue to prioritize glycogen storage in adipose tissue instead of muscle.

If the exercise stimulus is significant enough, insulin sensitivity will improve immediately as well as insulin independent glucose uptake.

How much bigger "reservoir" of glycogen storage opens up when insulin sensitivity is restored? It seems to my amateur eye that this is a pretty Big Deal, taking a trainee from being unable to do anything with carb but store it as fat to the ability to process it normally.
I remember that carb has a role in MPS, but can't remember the layman's take on that one.

Well insulin resistance occurs relatively "MORE" at the level of adipose tissue than skeletal muscle tissue, so becoming "more" sensitive to insulin will affect both storage of fat and glycogen storage at muscle. Additionally, a low carb diet tends to make people "insulin resistant" to a certain degree as lower amounts of glucose are being handled and preferentially used in tissues like the brain.

[Smyth]

Hey, Been, quit hogging him!!

[Bill Been]

Hey, Been, quit hogging him!!

Hey, I gave him 15 days to reply. It's not like he's in med school about to relocate and start a residency and running a research operation quantifying the observed effects of a Novice Linear Progression while re-desgining the doctor-patient health and wellness business model and getting barbell exercise coded as a treatment option for health insurers as he casually trains for a National Powerlifting championship meet. Frickin' slackers, man.

[Jordan Feigenbaum]

Hey, I gave him 15 days to reply. It's not like he's in med school about to relocate and start a residency and running a research operation quantifying the observed effects of a Novice Linear Progression while re-desgining the doctor-patient health and wellness business model and getting barbell exercise coded as a treatment option for health insurers as he casually trains for a National Powerlifting championship meet. Frickin' slackers, man.

To be fair, your post had moved to the 2nd page so it wasn't staring at me everyday!

[Bill Been]

To be fair, your post had moved to the 2nd page so it wasn't staring at me everyday!

Lest there be confusion, I was obliquely expressing my astonishment that you ever have time to respond to stuff here, much less a long-ass string of incoherent babble like I asked you to respond to. You're one of the Big Thinkers I've come across in my life. A guy who sees how things are, how they should be, and begins to work to close that gap, seemingly oblivious to the vastness of the undertaking. Continue and Godspeed.

[lou t]

Good questions, Bill. Answers inline:



It depends how much has been depletes if you're looking for it to be replenished in <20-24hrs. At that point (about a day) most muscle glycogen can be refilled without any carbohydrates unless there has been an exhaustive workout or total cals are very low.



Depends really. Big picture, however, is that if you have depleted muscle glycogen and significant amounts of liver glycogen stores- you're going to replenish the liver's stores first (60-100g total) and then the muscles (~350g total) while maintaining blood sugar and sugar supply to the brain via ingesting carbs, creating new sugar (gluconeogensis), or releasing stored sugar from the liver (glycogenolysis).



Eh, the volume isn't TERRIBLY high but then the relative intensity is pretty high and depending on who you read, glucose can be oxidized at the level of the muscle at a rate of about 200kCal/kg/min of activity. Let's say a person on LP does 3 sets of 5 squats, benches, and 1x5 of deadlifts and that in addition to this- his/her last warm ups also are relatively intense. So I'm not sure how many total "minutes" of intense exercise, but we'd expect a really big decrease in intramuscular glycogen, right? WRONG. Most evidence suggests intramuscular glycogen levels "only" fall by about 30% post exhaustive exercise as measured by biopsy. For instance, one of classic studies had folks do front squats, back squats, leg press, and leg extensions x 5 sets each and muscle glycogen levels only fell by 26%.



Probably about the same, to be honest, unless the volume is extremely different.



Gluconeogensis will help make glucose that will get stored in the muscle after the liver is mostly full.



Muscle glycogen does not contribute to blood sugar levels, but low levels of muscle glycogen are constantly turning over as you're active- even at relatively low intensities. That said, energy from lipid oxidation is allowed to contribute to a higher level at lower intensities.



Yes.



If the exercise stimulus is significant enough, insulin sensitivity will improve immediately as well as insulin independent glucose uptake.



Well insulin resistance occurs relatively "MORE" at the level of adipose tissue than skeletal muscle tissue, so becoming "more" sensitive to insulin will affect both storage of fat and glycogen storage at muscle. Additionally, a low carb diet tends to make people "insulin resistant" to a certain degree as lower amounts of glucose are being handled and preferentially used in tissues like the brain.

Fwiw, this is a brilliant post. I've done a fair amount of reading on this subject and love this discussion.

Bill thanks for teeing it up

[Jordan Feigenbaum]

Lest there be confusion, I was obliquely expressing my astonishment that you ever have time to respond to stuff here, much less a long-ass string of incoherent babble like I asked you to respond to. You're one of the Big Thinkers I've come across in my life. A guy who sees how things are, how they should be, and begins to work to close that gap, seemingly oblivious to the vastness of the undertaking. Continue and Godspeed.

Thank you, Bill. I will try and live up to that description