Author Topic: How much glycogen  (Read 2022 times)

quixoticgeek

  • Mostly Harmless
How much glycogen
« on: January 25, 2018, 10:39:54 pm »

Been wondering, how much glycogen does the average person carry round with them? I know this isn't exactly an easy thing to quantify as there's no such thing as an average person, and it probably depends on if you had a big breakfast, or large meal the night before. But I'm wondering if there's a way to get a ballpark figure of approximately the right magnitude for how many calories one might reasonably expect to be able to draw upon in terms of glycogen reserves?

Thanks

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: How much glycogen
« Reply #1 on: January 25, 2018, 11:05:57 pm »
from google:
"Skeletal muscles store about 400 grams or glycogen, the liver stores 90 to 110 grams of glycogen and your blood circulates roughly 25 grams as glucose. This means your body is capable of storing about 2,000 calories of carbohydrates."

simonp

  • Omnomnomnipotent.
Re: How much glycogen
« Reply #2 on: January 25, 2018, 11:22:06 pm »
2000 was the number I had in my head.

Re: How much glycogen
« Reply #3 on: January 26, 2018, 11:30:18 am »
~16 miles at marathon pace or faster, which is likely around 2,000 calories give or take.

If I haven't done any fasted rides, I seem to manage about 45 miles on the bike without food/blowing up. After a few long fasted rides 60 miles is easy, so could presumably go further.


ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: How much glycogen
« Reply #4 on: January 26, 2018, 12:03:16 pm »
After a few long fasted rides, you are probably getting better at using the 100,000 calories or so of stored fat
“Procrastination is the thief of time, collar him.” –Charles Dickens

simonp

  • Omnomnomnipotent.
Re: How much glycogen
« Reply #5 on: January 26, 2018, 12:31:54 pm »
I found structured training improved my fat burning more effectively than fasted or low intake long rides. I expect I was probably going catabolic and doing more harm than good.

Haven’t had it checked recently but I’m losing body fat while training so I’m burning fat somewhere.

T42

  • Old fool in a hurry
Re: How much glycogen
« Reply #6 on: January 26, 2018, 01:22:01 pm »
I read of a study some years ago which showed that if you take a 5-minute rest after an hour's endurance-level exercise you begin burning fat earlier than if you don't rest. I've had some corroboration of this myself, but since I rarely rest without eating a bar or similar it's hard to say that it works.
I dare eat all that may become a man.

But hold the oysters.

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: How much glycogen
« Reply #7 on: January 26, 2018, 03:05:03 pm »
sounds like you know what you are doing with this, and being more disciplined than I am with it at the moment
“Procrastination is the thief of time, collar him.” –Charles Dickens

LEE

  • "Shut Up Jens" - Legs.
Re: How much glycogen
« Reply #8 on: January 26, 2018, 11:33:04 pm »
Audax plus Intermittent fasting trained my body to use fat/ketones effectively.

It's what humans are supposed to do.  Burning fat, and metabolising Keytones, is our normal, evolved state, not burning sugars.

It's the last 60 years of cheap, easy-access,  Carbs that made us all carb-dependent and "bonked" when the Glycogen burned up after 2 hours (when you still have weeks worth of fat fuel stored).

I've cycled perfectly comfortable after 4 days of zero calories, you just need to make sure you stay in a fat-burning zone.  Audax is typically fat-burning cycling.

The answer to the question though is, I think, about 2,000kcals.  That's why non-cyclists, on the London-Brighton ride, "bonk" about 2-3 hours in.  They've been burning glycogen at 600-1000kcals an hour and it's all gone.  They aren't adapted to metabolise fat ...so they bonk. They're on empty.  A fat-burning cyclist will cycle 50 miles without any difficulty, without the need for carbs.  It just needs time to "train" your metabolism.  It hurts at first.

Our snacking culture (which shuts off fat-burning immediately) means that we've generally lost our ability to metabolise the very fuel we spent millions of years evolving to use the most efficiently.
Some people say I'm self-obsessed but that's enough about them.

T42

  • Old fool in a hurry
Re: How much glycogen
« Reply #9 on: January 27, 2018, 11:51:30 am »
^^^ hence the burgeoning middles and John Timpson's League of Pear-Shaped Men.

Re the "60 years", I reckon it goes back a lot further than that, 150 at least to judge from Gladstone's aversion for dentists.
I dare eat all that may become a man.

But hold the oysters.

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: How much glycogen
« Reply #10 on: January 27, 2018, 12:21:17 pm »
Audax plus Intermittent fasting trained my body to use fat/ketones effectively.

It's what humans are supposed to do.  Burning fat, and metabolising Keytones, is our normal, evolved state, not burning sugars.

It's the last 60 years of cheap, easy-access,  Carbs that made us all carb-dependent and "bonked" when the Glycogen burned up after 2 hours (when you still have weeks worth of fat fuel stored).

I've cycled perfectly comfortable after 4 days of zero calories, you just need to make sure you stay in a fat-burning zone.  Audax is typically fat-burning cycling.

The answer to the question though is, I think, about 2,000kcals.  That's why non-cyclists, on the London-Brighton ride, "bonk" about 2-3 hours in.  They've been burning glycogen at 600-1000kcals an hour and it's all gone.  They aren't adapted to metabolise fat ...so they bonk. They're on empty.  A fat-burning cyclist will cycle 50 miles without any difficulty, without the need for carbs.  It just needs time to "train" your metabolism.  It hurts at first.

Our snacking culture (which shuts off fat-burning immediately) means that we've generally lost our ability to metabolise the very fuel we spent millions of years evolving to use the most efficiently.

For the normal, healthy human I'd agree with everything you said, and nutritional ketosis for endurance exercise is definitely achievable for most of us.
“Procrastination is the thief of time, collar him.” –Charles Dickens

T42

  • Old fool in a hurry
Re: How much glycogen
« Reply #11 on: January 27, 2018, 02:49:53 pm »
^^^ hence the burgeoning middles and John Timpson's League of Pear-Shaped Men.

Re the "60 years", I reckon it goes back a lot further than that, 150 at least to judge from Gladstone's aversion for dentists.

That being said, potato starch will rot teeth even better than sugar.
I dare eat all that may become a man.

But hold the oysters.

hellymedic

  • Just do it!
Re: How much glycogen
« Reply #12 on: January 27, 2018, 05:33:11 pm »
[Random historical musings]

I think tooth decay was observed in Ancient Greeks who ate many figs.

I speculate that Esau sold his birthright to Jacob for a bowl of lentil soup because he was bonked out from a morning's hunting (lots of short, sharp anaerobic sprints).

Re: How much glycogen
« Reply #13 on: January 27, 2018, 05:37:03 pm »
[Random historical musings]

I think tooth decay was observed in Ancient Greeks who ate many figs.

I speculate that Esau sold his birthright to Jacob for a bowl of lentil soup because he was bonked out from a morning's hunting (lots of short, sharp anaerobic sprints).

Lentil and goat?

:)


quixoticgeek

  • Mostly Harmless
Re: How much glycogen
« Reply #14 on: January 30, 2018, 06:55:42 pm »
Audax plus Intermittent fasting trained my body to use fat/ketones effectively.

It's what humans are supposed to do.  Burning fat, and metabolising Keytones, is our normal, evolved state, not burning sugars.

It's the last 60 years of cheap, easy-access,  Carbs that made us all carb-dependent and "bonked" when the Glycogen burned up after 2 hours (when you still have weeks worth of fat fuel stored).

I've cycled perfectly comfortable after 4 days of zero calories, you just need to make sure you stay in a fat-burning zone.  Audax is typically fat-burning cycling.

4 days is impressive!

Is there an easy way based on heart rate to know where the fat burning zone is?

On Saturday I did my first 200k audax. My Wahoo reckons I burned 5200kcal over the 12:54 I was riding. On the day I consumed:

2 cheese & Ham rolls for breakfast.
Glass of orange juice
mars bar
cheese toastie (CP 1)
M&M's ~100gm
Chocolate digestives ~90gm
Chips (portion size unknown)
400ml coke
500ml fanta.

I'm not sure the exact numbers, but I make that something in the 2000-3000kcal range. I did notice towards the end that I was starting to flag a bit (yay for cadence meter), and even stopped with just 1km to go for a handful of M&M's just to give me a kick to get there.

Quote

The answer to the question though is, I think, about 2,000kcals.  That's why non-cyclists, on the London-Brighton ride, "bonk" about 2-3 hours in.  They've been burning glycogen at 600-1000kcals an hour and it's all gone.  They aren't adapted to metabolise fat ...so they bonk. They're on empty.  A fat-burning cyclist will cycle 50 miles without any difficulty, without the need for carbs.  It just needs time to "train" your metabolism.  It hurts at first.

Our snacking culture (which shuts off fat-burning immediately) means that we've generally lost our ability to metabolise the very fuel we spent millions of years evolving to use the most efficiently.

How does one go about training one's metabolism? What are the long term side effects of switching to ketotonic energy production?

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

Re: How much glycogen
« Reply #15 on: January 31, 2018, 10:59:08 am »
Audax plus Intermittent fasting trained my body to use fat/ketones effectively.

It's what humans are supposed to do.  Burning fat, and metabolising Keytones, is our normal, evolved state, not burning sugars.

It's the last 60 years of cheap, easy-access,  Carbs that made us all carb-dependent and "bonked" when the Glycogen burned up after 2 hours (when you still have weeks worth of fat fuel stored).

I've cycled perfectly comfortable after 4 days of zero calories, you just need to make sure you stay in a fat-burning zone.  Audax is typically fat-burning cycling.

4 days is impressive!

Is there an easy way based on heart rate to know where the fat burning zone is?

On Saturday I did my first 200k audax. My Wahoo reckons I burned 5200kcal over the 12:54 I was riding. On the day I consumed:

2 cheese & Ham rolls for breakfast.
Glass of orange juice
mars bar
cheese toastie (CP 1)
M&M's ~100gm
Chocolate digestives ~90gm
Chips (portion size unknown)
400ml coke
500ml fanta.

I'm not sure the exact numbers, but I make that something in the 2000-3000kcal range. I did notice towards the end that I was starting to flag a bit (yay for cadence meter), and even stopped with just 1km to go for a handful of M&M's just to give me a kick to get there.

Quote

The answer to the question though is, I think, about 2,000kcals.  That's why non-cyclists, on the London-Brighton ride, "bonk" about 2-3 hours in.  They've been burning glycogen at 600-1000kcals an hour and it's all gone.  They aren't adapted to metabolise fat ...so they bonk. They're on empty.  A fat-burning cyclist will cycle 50 miles without any difficulty, without the need for carbs.  It just needs time to "train" your metabolism.  It hurts at first.

Our snacking culture (which shuts off fat-burning immediately) means that we've generally lost our ability to metabolise the very fuel we spent millions of years evolving to use the most efficiently.

How does one go about training one's metabolism? What are the long term side effects of switching to ketotonic energy production?

J

That last question opens up a whole can of worms

quixoticgeek

  • Mostly Harmless
Re: How much glycogen
« Reply #16 on: January 31, 2018, 11:10:34 am »

How does one go about training one's metabolism? What are the long term side effects of switching to ketotonic energy production?

J

That last question opens up a whole can of worms

Are canned worms safe to consume as part of a ketogenic diet?

J
--
Beer, bikes, and backpacking
http://b.42q.eu/

simonp

  • Omnomnomnipotent.
Re: How much glycogen
« Reply #17 on: January 31, 2018, 11:17:16 am »

How does one go about training one's metabolism? What are the long term side effects of switching to ketotonic energy production?

J

That last question opens up a whole can of worms

https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/1108558



Are canned worms safe to consume as part of a ketogenic diet?

J

LEE

  • "Shut Up Jens" - Legs.
Re: How much glycogen
« Reply #18 on: January 31, 2018, 01:24:26 pm »
Audax plus Intermittent fasting trained my body to use fat/ketones effectively.

It's what humans are supposed to do.  Burning fat, and metabolising Keytones, is our normal, evolved state, not burning sugars.

It's the last 60 years of cheap, easy-access,  Carbs that made us all carb-dependent and "bonked" when the Glycogen burned up after 2 hours (when you still have weeks worth of fat fuel stored).

I've cycled perfectly comfortable after 4 days of zero calories, you just need to make sure you stay in a fat-burning zone.  Audax is typically fat-burning cycling.

4 days is impressive!

Is there an easy way based on heart rate to know where the fat burning zone is?

On Saturday I did my first 200k audax. My Wahoo reckons I burned 5200kcal over the 12:54 I was riding. On the day I consumed:

2 cheese & Ham rolls for breakfast.
Glass of orange juice
mars bar
cheese toastie (CP 1)
M&M's ~100gm
Chocolate digestives ~90gm
Chips (portion size unknown)
400ml coke
500ml fanta.

I'm not sure the exact numbers, but I make that something in the 2000-3000kcal range. I did notice towards the end that I was starting to flag a bit (yay for cadence meter), and even stopped with just 1km to go for a handful of M&M's just to give me a kick to get there.

Quote

The answer to the question though is, I think, about 2,000kcals.  That's why non-cyclists, on the London-Brighton ride, "bonk" about 2-3 hours in.  They've been burning glycogen at 600-1000kcals an hour and it's all gone.  They aren't adapted to metabolise fat ...so they bonk. They're on empty.  A fat-burning cyclist will cycle 50 miles without any difficulty, without the need for carbs.  It just needs time to "train" your metabolism.  It hurts at first.

Our snacking culture (which shuts off fat-burning immediately) means that we've generally lost our ability to metabolise the very fuel we spent millions of years evolving to use the most efficiently.

How does one go about training one's metabolism? What are the long term side effects of switching to ketotonic energy production?

J

2 cheese & Ham rolls for breakfast.
Glass of orange juice
mars bar
cheese toastie (CP 1)
M&M's ~100gm
Chocolate digestives ~90gm
Chips (portion size unknown)
400ml coke
500ml fanta.


Sounds more like you attended a 7 year old's birthday party !!

I'm not medically qualified so take this with a pinch of salt (waits for humorous dietary comment)...but..

Almost everything you consumed was a "quick hit" carb fuel and not optimal for a long steady ride. 
M&Ms, Coke, Fanta, Fruit Juice..etc will just spike your blood sugars briefly and then leave you to crash afterwards. 
Far better to have a bag of Mixed Nuts, simple carbs, Oatmeal porridge..etc. (There are websites for slowburn endurance carbs).

I've used sweets myself* (Jelly Babies are the accepted "help me over the final 20km" emergency fuel) but I wouldn't recommend the amount of refined sugar that you ate.

* Nothing works for me like a pint of Bitter Shandy when there's 20-30k to go.

As for the Fat-Burning Zone, I'd use the rule of thumb that, if you can chat away to a fellow cyclist, without getting out of breath, you're probably in Z2 or thereabouts. 

As for adapting to burning fat efficiently there's no real shortcuts to actually riding in the zone, without eating.  My first year of Audax was a story of eating, bonking & being starving hungry.  That improved over time to the point I could do a summer 200 without much more than a bowl of soup.

The long term side effects of a "fasted" lifestyle are positive.  It's how we evolved to live.  What we do now (Constant Carbs intake) is a very recent change (see: "Type 2 diabetes" and "epidemic").



Some people say I'm self-obsessed but that's enough about them.

LittleWheelsandBig

  • Whimsy Rider
Re: How much glycogen
« Reply #19 on: January 31, 2018, 01:49:07 pm »
In my experience, consuming carbs while actually exercising fairly hard (as opposed to sitting still) prevents blood sugar spikes. That said, the fitter I am, the less food I need during a brevet.
Wheel meet again, don't know where, don't know when...

Re: How much glycogen
« Reply #20 on: January 31, 2018, 02:53:41 pm »
There seems to be a bit of a vicious circle with doing long bike rides that have the pace set for you, if that pace is a bit high (doesn't matter if it's an audax where the time limit is a stretch or a group ride where you are slow for the group). To go the distance, you need to be able to burn fat, but to keep up you need to ride hard, and you can't do both. 
The healthy alternatives seem: to become fat adapted and able to ride at a higher effort while burning fat, or to train your power upwards such that keeping up exerts less strain on your body. The easy way out (one I have taken before) is to fuel yourself with sugar for the whole ride!

simonp

  • Omnomnomnipotent.
Re: How much glycogen
« Reply #21 on: January 31, 2018, 03:02:40 pm »
Going from an untrained state of 25% of energy from fat at moderate pace to a trained state of 70% of energy from fat at a moderate pace makes a huge difference to the amount of energy intake required to keep going.

hellymedic

  • Just do it!
Re: How much glycogen
« Reply #22 on: January 31, 2018, 03:14:07 pm »
Indeed.
Those with a low aerobic capacity will working in a higher zone for a given power output and need a higher carb level despite training.

LEE

  • "Shut Up Jens" - Legs.
Re: How much glycogen
« Reply #23 on: January 31, 2018, 04:50:08 pm »
In my experience, consuming carbs while actually exercising fairly hard (as opposed to sitting still) prevents blood sugar spikes. That said, the fitter I am, the less food I need during a brevet.

The problem is with how sugars are released into the blood though. 
Refined sugars are basically just dumped into the blood quickly whereas unrefined sugars tend to "seep in" over a longer period. 
Far better in my experience to keep the fuel trickling in over a long period, so you can keep it topped up, than suddenly bonking.

Far better still not to be totally reliant on Carbs.

Worth noting that the cold winter weather increases your energy requirements significantly.  Even in Winter Bib-Tights your legs will be radiating a lot of body heat away unnoticed.
Some people say I'm self-obsessed but that's enough about them.

simonp

  • Omnomnomnipotent.
Re: How much glycogen
« Reply #24 on: January 31, 2018, 04:51:58 pm »
The gut can only absorb about 60g of sugar per hour.

It's really not an excessive intake when working hard.