T Nation

Glycogen Storage



If a person is glycogen depleted, then eats a meal of carbs, is glycogen stored first in the liver or muscles?

Or is it simultaneously stored in both?




2nd post from Stu (spoiler:Liver).


You should never get to a state of full glycogen depletion in the first place. If you do, you are doing something very wrong.





Says who?


Refer here:



Facinating. I'm not sure I want to try this myself, but I am becoming more and more aware of the importance of fats in our diets. Our ancestors ate very little in the way of carbohydrates, and we managed to evolve as a species nonetheless.


And see some of these too for your interest.

I have more, but these deal with carbo loading after depletion (except for the one by Phinney). These are some of the studies I have reviewed for a report.

Burke, L.M., Angus, D.J., Cox, G.R., Cummings, N.K., Febbraio, M.A., Gawthorn, K.,
Hawley, J.A., Minehan, M., Martin, D.T., & Hargreaves, M. (2000). Effect of fat adaptation and carbohydrate restoration on metabolism and performance during prolonged cycling. Journal of Applied Physiology, 89, 2413-2421

Burke, L.M., Hawley, J.A., Angus, D.J., Cox, G.R., Clark, S.A., Cummings, N.K.,
Desbrow, B., & Hargreaves, M. (2001). Adaptations to short-term high-fat diet persist during exercise despite high-carbohydrate availability. Medicine and Science in Sports and Exercise, 34, 83-91.

Carey, A.L., Staudacher, H.M., Cummings, N.K., Stepto, N.K., Nikolopoulos, V., Burke,
L.M., & Hawley, J.A. (2001) Effects of fat adaptation and carbohydrate restoration on prolonged endurance exercise. Journal of Applied Physiology, 91, 115-122.

Johnson, N.A., Stannard, S.R., Mehalski, K., Trenell, M.I., Sachinwalla, T., Thompson,
C.H., & Thompson, M.W. (2003). Intramyocellular triacylglycerol in prolonged cycling with high- and
low-carbohydrate availability. Journal of Applied Physiology, 94, 1365-1372.

Lambert, E.V., Goedecke, J.H., Van Zyl, C., Murphy, K., Hawley, J.A., Dennis, S.C. &
Noakes, T.D. (2001). High fat diet versus habitual diet prior to carbohydrate loading: effects on exercise metabolism and cycling performance. International Journal of Sports Nutrition and Exercise Metabolism, 11, 209-225.

Phinney, S.D. (2004). Ketogenic diets and physical performance. Nutrition and
Metabolism, 1.

Staudacher, H.M., Carey, A.L., Cummings, N.K., Hawley, J.A. & Burke, L.M. Short-
term high fat diet alters substrate utilization during exercise but not glucose tolerance in highly trained athletes. International Journal of Sports Nutrition and Exercise Metabolism, 11, 273-286.

Sterlingwerff, T., Spriet, L.L., Watt, M.J., Kimber, N.E., Hargreaves, M., Hawley, J.A. &
Burke, L.M. (2005). Decreased PDH activation and glycogenolysis during exercise following fat adaptation with carbohydrate restoration. American Journal of Applied Physiology, Endocrinology, and Metabolism, 290, 380-388.


Check this:



I estimated that a persons average glycogen storage make up about 2500-3000 kcal (right/wrong)?

Would it be a reasonable guess to say that I'd be able to deplete my glycogen stores in one day i I did intense exercise and ate very little carbs?


The stereotypical 70 kg male can store 100 grams in the liver and 400 grams in his muscles. Which I'd guess is 2000 calories. But a "very muscular man" can store up to 1000 grams. No idea how muscular he'd have to be.

And you don't just use glycogen. Fat and your precious muscle will also be used.

But it's been said that "you pretty much use all your glycogen in the first two hours of a marathon", so you'd probably be able to deplete your glycogen stores in a day if you exercised.

varfor du nu skulle vilja gora det


Or no carbs.

Yes. You could. It would be hard. The key would be intensity, since low-intensity activities use fat the preferential fuel.

That's why "carb-loading" for an endurance event is such a stupid idea.


hahaha Bricknyce is my new favorite member, hahaha hes legit and backs up everything he says. You rock bro....dude picks a bone with whoever lol. (I'm a neb but have read since about 08, went thru a phase that I just wanted to get bigger at whatever cost...lol, realized I've got the genes to be a runner and will prob make our nats olypic team for london 2012 as a 10000meter/marathoner,) So I gave up the weights, untill this phase is over....Can't wait to get back at the iron. I'm legit tho and LOVE BBing and will lift and eat my way to fill out my lanky 6'1 frame after the running ends, I LOVE BBing more than anything.

sorry for the rant just don't want to be judged by my avatar!

I was about to give a little rant about glycogen (3rd year med student, know a little about it) but read his post .......lol. nice



According to Lehninger's Biochemistry textbook a 70kg male can hold approx .225kg of glycogen via liver and muscle. And my professor, (Phd in Biochemistry, M.s. in Nutritional something or other) uses the figures of 10% of liver mass can be glycogen so 500g liver=50g hepatic glycogen. and 2% of muscle tissue as glycogen (I think it'd be tough to do an actual estimation of "muscle" tissue without DEXA scan).

Since training can affect capacity and etc. So take those above numbers as an AVG for a non training person.


Performing intensive exercise (80-90% of VO2max) has been estimated to expend 150 g of CHO per hour on 70-kg male. In addition brains use roughly 100 g per day, if you are not used to use fat as a fuel. So, if glycogen storages are about 500 grams, then e.g. 2 hours of intensive exercise (plus brain work) and CHO restriction may cause that the stores are pretty much empty even in a day.

kakno, jag vet inte det...


There are many claims that fasting and restricting carbs does not catabolize muscle. HGH release during fasting is said to prevent muscle breakdown and increase body fat metabolism for energy expenditure.

And concerning muscle catabolism I'm going to test if the theory in the article; "Protein Cycling for Maximum Gains" holds true. I consume MCT:s daily so there will be fuel available most of the time. Also my fat consumption is quite high so catabolism because of energy deficit isn't something I worry about.

What created my idea to test out a new complex macro-nutrient cycling diet was reading about "the warrior diet", HGH:s relationship to fasting and a suggestion that Carb cycling might increase glycogen storage capacity. Seems plausible that my body would try to increase storage capacity if I deplete the storages with regular intervals. This is however just a hypothesis.

Now can anybody tell me how fast I can manage to "fill" my glycogen storages?


Sure regular depletion and refilling the glycogen stores with exercise and dietary manipulation would increase the capacity to store CHO. That's quite well known to happen among those who train/do sports regularly. How fast you can refill your stores depends mainly on how depleted the stores are and how much carbs you are consuming. If the stores are more or less empty, I have seen estimates that 500-700 g of CHO are needed to refill the stores. That's quite a lot. Also, some of those ingested carbs are used by e.g. brain and energy production in general, so I would quess that the amoung needed would be close to that 700 grams. Personally I have noticed that my stores are empty if I feel crappy; no energy (for pretty much anything, let alone training), brain fog, feeling cold, etc. After emptying the stores, if I go crazy with carbs I may feel good on the next day, but usually I need two days to feel strong.


"Now can anybody tell me how fast I can manage to "fill" my glycogen storages?"

With a traditional carb loading scheme.


Here's a basic outline on how to properly deplete/load carbs--just posted this over on the BB section:


Glycogen stores can be depleted a lot faster than replenished, right? If so wouldn't a 2 days depletetion followed by 3 days loading make more sense than 2 days depletion and 2 days loading?

Or should i trust that I'll learn to feel when my glycogen levels has peaked?

I think I'd be able to deplete my glycogen in 2 days since I have had days with almost no carbs and they've worked out just fine, so during depletion days I will use almost no carbs.