Glycogen

Dean · Glycogen

I was wondering what people's takes are on the subject of glycogen... especially in skeletal muscle?

Bear was always stating that glycogen stores remain unchanged, no matter what type of diet a person is on. He said muscle glycogen was never used for fuel by the muscle, and that glycogen is simply there to supply emergency glucose to the blood. I have read a lot that contradicts this theory.

What I have come to understand about glycogen stores is:

* Liver glycogen makes up about 1/3 of the glycogen stores in the body, and muscle glycogen make up 2/3.

* About 10% of the weight of the liver is glycogen.

* Liver glycogen is what is used to keep the blood levels of glucose at a steady amount. It does it via glucagon (a hormone released by the pancreas). Liver cells have glucagon receptors.

* Muscle glycogen CANNOT be used for blood glucose needs, because muscle cells lack glucagon receptors. Also, the enzyme hexokinase in muscle cells is so high that any free glucose from glycogenolysis of glycogen in the muscles is immediately phosphorylated and enters the glycolytic pathway. The reason for the temporary appearance of the free glucose from glycogen is the need of the skeletal muscle cell to generate energy from glucose oxidation, thereby, precluding any chance of the glucose entering the blood. Muscle glycogen is therefore used by the muscle cells for anaerobic respiration via glycolysis... production of ATP (for quick energy) in the absence of oxygen, producing lactic acid as a byproduct... causing that muscle burn when doing hard intense exercise.

* When you fill your glycogen stores, it is 1/4 glycogen and 3/4 water. When you empty your glycogen stores, you lose weight... but it's basically all that water and glycogen that you are losing. And, if you binge on carbs, you will gain all that glycogen and water back... it won't go to fat. This amounts to around five pounds... and I have experienced it first hand. Intense exercise will "burn away" the "calories" of a high carb binge in a day. You'll gain five pounds and you'll lose five pounds very quickly. Which adds to the argument that on a no carb diet, glycogen stores must be low.

As far as glycogen stores being completely empty on a no carb diet, I have trouble with this. Liver glycogen is there to keep blood glucose steady. That is such an important need, I doubt these levels would drop to zero. And, for muscles, it seems there would be some needed for "fight or flight" situations.

In a fully FFA-adapted individual, are glycogen stores just at a lower level, or what? I tried to ask Bear this question several times in his thread... but, he kept saying glycogen stores are always the same level no matter one's diet. And he said muscle glycogen is never used for fuel. This just did not seem to be correct.

Even if muscle glycogen levels were low, it seems there would still need to be some fuel that could be burned without oxygen, for quick energy needs. I'm sure that the more one adapts to using fat as fuel, the muscle cells will use fat over glucose more and more, therefore not really touching the glycogen stores unless in absolute oxygen deprived situations, like immediate (emergency) energy needs.

Any thoughts on this?

BTW... this is often used by LC bashers to point out the fact that we NEED carbs in order to keep our glycogen stores up for exercise. For intense activity, it is often recommended that one "carb load" in order to have sufficient fuel for the muscles. In fact, the idea of carb loading is taken to the point of trying to get "as much glycogen in one's muscles as possible" by "training" the muscle to uptake more and more glycogen. The way to do this, it is advised, is to eat a whole bunch of carbs right after intense physical exercise (after the muscle glycogen stores have been emptied). They want you to basically "overload" the muscles with glycogen, so as to have a lot to use in competition.

Even body builders use this approach, with a slight twist. They will LC for days and empty their stores, and then eat tons of carbs to "pump up" the muscles with glycogen... like right before a "show". Seems quite ridiculous IMHO!

jl53563

Deano, from the Phinney study, it appears that after the glycogen is initially reduced, it stays at a reduced level.

"The bicyclist subjects of this study noted a modest decline in their energy level while on training rides during the first week of the Inuit diet, after which subjective performance was reasonably restored except for their sprint capability, which remained constrained during the period of carbohydrate restriction. On average, subjects lost 0.7 kg in the first week of the EKD, after which their weight remained stable. Total body potassium (by 40K counting) revealed a 2% reduction in the first 2 weeks (commensurate with the muscle glycogen depletion documented by biopsy), after which it remained stable in the 4th week of the EKD. These results are consistent with the observed reduction in body glycogen stores but otherwise excellent preservation of lean body mass during the EKD."

And, even after strenuous exercise, muscle glycogen was not depleted.

"At this high level of energy expenditure, it is notable that the second test was performed at a mean respiratory quotient of 0.72, indicating that virtually all of the substrate for this high energy output was coming from fat. This is consistent with measures before and after exercise of muscle glycogen and blood glucose oxidation (data not shown), which revealed marked reductions in the use of these carbohydrate-derived substrates after adaptation to the EKD."

Dean

jl53563

"I'm just glad that my favorite physical activity is backpacking. Make that my second favorite. "

And they're both great exercise!!!

Heather

jl53563

LOOPS · Tennis experiments continue

Well my experiments with tennis continue...

Today I wussed out and had a banana and some chocolate on top of my usual egg yolks and eggs beforehand to see what happened, as yesterday was a real effort on the court. Even my trainer has taken to calling me 'abuela' which although funny isn't really where I want to be!

I just dunno - I 'thought' at one point I could sprint more, but it seemed like my power and concentration was less for hitting the ball. Sigh....what to do next. I tried eating a big steak an hour before tennis yesterday but that seemed to make my performance even worse than usual.

Darn it - I want to be a fat-burning carnivore but I love my tennis too. I hope this works itself out. I think it is important to have an empty stomach before I train as this hinders me too.

Loops

ReddyMcMeaty

Loops have you tried coconut oil? As long as you're experimenting you might want to give that a go. It acts "as a carb" and is burned quickly, because it's a medium chain fatty acid rather than a long chain. I'll put a few quotes in about them. They MIGHT help your workouts, maybe taken in some coffee or with some caffeine and ephedrine for the extra energy if you're determined to be low carb and need the zippiness, unless you're not allowed to take Eph. of course!! I'm pretty experienced with it if you have any questions.

One thing to take into consideration.. if you've never taken coconut oil you might experience loose bowels if you take too much at once, so start with just a teaspoon and work your way up to a few tablespoons. I've never had an issue, but some people are running to the toilet....

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Medium-chain triglycerides (MCT) are a class of fatty acids. Their chemical composition is of a shorter length than the long-chain fatty acids present in most other fats and oils, which accounts for their name. They are also different from other fats in that they have a slightly lower calorie content1 and they are more rapidly absorbed and burned as energy, resembling carbohydrate more than fat.2
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from getbig.com
Medium Chain Triglycerides (MCT)
MCT's are technically fats, but they have very unique properties. The difference between them and other fats lies in their molecular structure. MCT's are shorter than other fats, which allows them to be burned rather quickly by the body for energy. MCT's enter the mitochondria, the powerhouse of a cell, without assistance, and do not require the usual transport mechanism.

MCT's are an attractive supplement because of their calorie density. They have 9 calories per gram, like fats, but lack the disposition to be stored as fat. All fats are not created equal. Research shows that animals maintain a lower bodyfat when they use MCT's in place of traditional fats.

They can help you increase lean muscle tissue, decrease excess bodyfat and fuel precompetition workouts.
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From bodybuilding.com :
Don't fall back into the out dated notion that consuming EFA's will cause an increase in body fat storage as this is far from the truth. Because EFA's are in such high demand by your body for proper structural, hormonal (read: testosterone production), and electrical functions, there is a negligible chance that they will be stored as body fat. In fact, since EFA's provide a significant amount of energy to your heart and other organs, your metabolic rate is increased and the body burns fat at a much faster rate. Rounding out the list of ingredients scientifically designed to keep you lean and rock hard while packing on new mass, medium chain triglycerides, also known as MCT's. MCT's are a unique "fat-less" fat designed to enter the bloodstream directly and convert immediately to glucose to be used as energy.

Think of MCT's as a fuel reservoir for your muscles that will help blast you through your intense workouts. In fact, MCT's actually resemble a carbohydrate more than a fat. Research has also shown that MCT's increase thermogenesis, accelerating your body?s ability to melt off unwanted body fat! With all the scientific mass accelerating agents in MX Pro40, you might expect that the taste is less than appealing. This is definitely not the case. MX Pro40 is a rich, creamy shake that will leave you craving serving after delicious serving. MX Pro40 is so good, you can eat it with a spoon! MX Pro40 is the perfect choice to support your muscles with first class bodybuilding nutrition. With 40 grams of a scientifically structured dual protein matrix, plus lean accelerating agents such as glutamine peptides, calcium, MCT's, and EFA's, be prepared to accelerate your gains to the next level and beyond!
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jl53563

Wow, some great info, Meg.

LOOPS

Thanks Meg -

I may give the coconut oil another shot. I think I tried it awhile back and it made my eczema flare up for some reason - don't think it did much for my tennis at the time.

It's really weird, because there HAVE been a few tennis lessons where I don't have much problem - I mean I wouldn't say I'm really pounding round the court but I've been ok. However there have been too many times where I'm just dying on court thinking - I need some carbs to do this properly!!

I do eat goats cheese which is really high in MCTs.

I remember protein powder helped a bit - which goes against what Bear says as it is fat that fuels not protein or carbs.

Maybe I am low on potassium too? I do feel tired some days.

Thanks once more - I'm not giving up yet!

Loops

ReddyMcMeaty

GOAT cheese? wow.. I had no idea..thanks! Gives me something yummy to eat in Spain ;)

mrfreddy · Re: Glycogen

ReddyMcMeaty

hitting the weights, along with some sprints will definitely minimize the damage done

Dean

If you don't mind it... just walk REAL fast for about two hours and you will burn away almost any carb binge you did the day before... PROVIDING your glycogen stores were REAL low (from eating VLC) right before the binge. NOT that I am advising anyone to do this. I think there is severe damage to your system from putting that much glucose (and it's accompanying insulin) into your system.

mrfreddy

thanks, I'll try something like that along with maybe some sessions in the weight room. At any rate, I'm going on vacation and that means a carb binge! always has, always will!

brklx · Re: Glycogen

[quote="Dean"]I was wondering what people's takes are on the subject of glycogen... especially in skeletal muscle?

Bear was always stating that glycogen stores remain unchanged, no matter what type of diet a person is on. He said muscle glycogen was never used for fuel by the muscle, and that glycogen is simply there to supply emergency glucose to the blood. I have read a lot that contradicts this theory.

Here is Bear on glycogen:

...A careful read of the article on

http://www.nutritionandmetabolism.com/content/1/1/2

reveals that contrary to the assertion, 'glycogen depletion' was not taken as a measure, only oxygen consumption. Glycogen STORAGE was reduced during the first TWO WEEKS and thereafter remained stable- not surprising since much of the reason for holding glycogen in the muscle tissue is the need to quickly remove glucose from circulation- it is much faster to convert glucose into glycogen than for the adipose tissues to convert it to bodyfat. Glycogen is not used up or 'depleted' during exercise, it functions only as quick, emergency source of blood glucose- and that is all. After withdrawal of carbs from the diet, the massive glycogen storage in the liver is also vastly reduced, thus facilitating blood flow through the hepatic vein from the lower body and preventing the 'stitch in the side' so commonly experienced during carb-loaded

Danny John

I'm wondering if gylcogen is like VO2 Max...

Let me explain...for years, athletes in the distance world have argued that VO2 Max is the key. Then, the Finns did a study with 5000 meter runners (elite) where the control group trained 'normal'...ran a lot...and the test group cut back mileage to 1/3 (I think) of the normal group and spent the time lifting weights...heavy weights.

As predicted, the test groups VO2 Max went down...a "bad" thing. But, on the track, the test group dropped their 5k time by an average of 30 seconds...an amazing thing!

So, is gylcogen like that? Do we give it a lot of importance...but it really isn't? Bodybuilders talk about gylcogen like it is the Holy Grail sometimes and they will stop and eat smarties before they do arm curls to "keep the stores up." But could it just be something that the body regulates really well and we shouldn't worry about it?

Dean

Dan,

Don't you think the glycogen stores will be different though, depending on one's diet? Won't this make a difference in how "pumped" the muscle looks, etc? As well as how performance will be affected?

Danny John

Seriously, Dean, I'm just wondering out loud if someday a researcher finds that it just isn't a big deal for an athlete or bodybuilder...

The body has amazing ways of dealing with things...again, just wondering because I hear the BBers talking about it all the time and most of them are weak as children.

TidalPool

Viking Dan

I think we were on the same list then. I remember Phillip's photos. Sheesh.

He could definitely be a poster boy for low carb. Of course, Anthony Colpo looks damn good, too.

TidalPool

Danny John

I remember Phillip started posting a lot of nude modeling shots of himself, too...

I will look this up...he had some excellent ideas...

Danny John

Here:

http://web.archive.org/web/200211...//www.geocities.com/paleofitness/

Danny John

While I was looking, I also found Tamir Katz...who started a great site back in the day with simple lifting programs...I haven't heard from him in about four years.