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How long does it take for glycogen to empty?


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After being unsuccessful in losing weight recently, I have recently gained some knowledge about glycogen stores and how beneficial it is for them to be empty in order for fat burning to be optimal. Tomorrow I am going on a diet that will consist of 100g of carbs a day for a little while and will consume around 1,600 cals total.

My question is, can glycogen stores be depleted in one day through physical activity? If so, how long does it take? I guess this may depend on the type of activity and for how long. I'm a wheelchair user and I push myself around for up to a mile a day when going out for leisurely activities or collecting food shopping.

I believe that I read something a long time ago that glycogen can be used up in around 15 minutes from weight lifting. Is this true? I never took much notice of the glycogen issue back then. If it is, then i guess glycogen can empty pretty easily.

Oh, one final question. Apart from the obvious weight gain, are there any tell tale signs that we have full glycogen stores so we can prevent weight gain?

 

 

 

19 Replies (last)

I am curious what the context was with respect to what you've been reading about glycogen.

Research has shown that people that burn fat during their workouts, burn less fat the rest of the day. The people who burn carbs during their workouts, burn more fat in the rest of the day, and while they sleep. So, when you considered the whole 24 hour period, it just came back to the old "calories in vs calories out" rule. It just didn't matter what the people burned during the workout. I light of that, I'd say that keeping you glycogen stores high enough to have very vigorous workouts is a good idea, unless you like very long, low intensity, workouts that you do while feeling low on energy.

Glycogen "empties" at a rate based on the dynamic balance between the rate of calorie burn, rate of digestion, rate of fat burning, and how much glycogen you start out with. I know it when mine runs out. At that point, I can only continue exerting at a lower level of intensity (which is probably the digestion and fat burning together). It doesn't feel good, but I am used to it (I do a lot of long (8+ hour) continuous efforts). 

some diets (like Lyle's UD2) have glycogen depleting workouts in them...and it takes a very long time at the gym, with lots and lots of painful sets per bodypart. The workout is specifically for glycogen depletion and lasts well over an hour, maybe 2 of high volume work. 15 minutes is just plain silly. So yes, its possible, but fully depleting glycogen takes a long time. Maybe I'll dig around bodyrecomposition.com, since I seem to remember someone asking a similar question a while ago...

#3  
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Thanks for the replies!

oldguysrule, I was studying on Google about this issue and several websites state that glycogen stores should be depleted in order for the body to start burning fat since it will first use glycogen as fuel. Only when that has run out, or near empty, will it finally start burning fat. Not only that, but a lot of protein should be consumed because the body will also turn to muscle for fuel, too. Since the dieting world is controversial, I guess this information could be right or wrong, depending who you ask.

I have an endomorphic body and have read that us endomorphs should be cutting back on our carbs, anyway. Instead of the 100g I was shooting for yesterday, today I have decided 150g, just to be a little more generous. Today is the first day and I feel okay so far with plenty of energy.

By the way, when I wrote that last post I really felt quite bad. I had a hard workout on Saturday (supposed to be a rest day but had to go somewhere fast!) and I think I felt the effects from it. I lacked focus, was fatigued and couldn't think straight. Not sure if these are signs of glycogen depletion but I stocked up on carbs last night and today I feel pretty good! I did read that a person won't gain weight from carb consumption if they are running low of glycogen since the carbs will be stored in the liver and muscle. Today, I didn't put weight on from my carb binge so I'm taking this as evidence that my glyocen was, indeed, low.

 

 

weight gain doesn't necessarily show itself over the course of one day or overnight you know. You're being too neurotic about it. It takes way more than you'd expect to spend muscle glycogen, and its not something to worry about since it won't happen unless you're trying to do it on purpose.

#5  
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That's what people said once when I had a cheesecake and pizza. That the weight will take it's time to pile on. The weight gain never did come! Like with any other aspects of dieting, everybody is different.

Read Good Calories, Bad Calories by Taubes, or even watch the documentary Fat Head.  You'll have a better understanding of how glycemic index plays a role in your weight loss.

A calorie just isn't a calorie.  I lost much weight using this site operating under that premise, but when all calories are restricted it's tough not to lose weight.  There can be a much more focused (and in my opinion even healthier) way to get the job done. 

I'm taking my last 20 or so pounds off using this method, and although general calories and nutrients play a role there is a bit more to the science of it all.

Original Post by sydpa97:

Read Good Calories, Bad Calories by Taubes, or even watch the documentary Fat Head.  You'll have a better understanding of how glycemic index plays a role in your weight loss.

A calorie just isn't a calorie.  I lost much weight using this site operating under that premise, but when all calories are restricted it's tough not to lose weight.  There can be a much more focused (and in my opinion even healthier) way to get the job done. 

I'm taking my last 20 or so pounds off using this method, and although general calories and nutrients play a role there is a bit more to the science of it all.

Fathead really educated me on fats! I love that movie, biased as it is- there is some great info in there.

Original Post by emilysmi:

Original Post by sydpa97:

Read Good Calories, Bad Calories by Taubes, or even watch the documentary Fat Head.  You'll have a better understanding of how glycemic index plays a role in your weight loss.

A calorie just isn't a calorie.  I lost much weight using this site operating under that premise, but when all calories are restricted it's tough not to lose weight.  There can be a much more focused (and in my opinion even healthier) way to get the job done. 

I'm taking my last 20 or so pounds off using this method, and although general calories and nutrients play a role there is a bit more to the science of it all.

Fathead really educated me on fats! I love that movie, biased as it is- there is some great info in there.

 It's biased by way of bashing super size me for sure...lol

The science though (which it covers in an entertaining way) is in actuality very sound (in my opinion).  From that movie alone one might question it for sure though.

#9  
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Thank you, syd!

I actually learnt from my own experience that perhaps calories are not just calories because I find it more difficult to lose weight eating junk, and easier to lose weight eating "clean".

I dared not say this before because I thought that popular opinion is that calorie is just a calorie. You wouldn't believe how many times I've read people say that it doesn't matter where the calories come from, and that weight loss can be achieved by eating anything.

While true to an extent, it's still more difficult to lose weight eating junk in my experience.

Original Post by sydpa97:

Read Good Calories, Bad Calories by Taubes, or even watch the documentary Fat Head.  You'll have a better understanding of how glycemic index plays a role in your weight loss.

A calorie just isn't a calorie.  I lost much weight using this site operating under that premise, but when all calories are restricted it's tough not to lose weight.  There can be a much more focused (and in my opinion even healthier) way to get the job done. 

I'm taking my last 20 or so pounds off using this method, and although general calories and nutrients play a role there is a bit more to the science of it all.

Both of those sources, Taubes and Fathead, are really misleading and the science on them is shaky at best, sorry to say. Both are entertainers, not scientists. Their stances on carbs and calories are really, really, really silly when actually put into the full light of research.

The muscles store a couple thousand cals and then there's the liver that also has a reserve.

The fitter the person the bigger the storage, 1-2 hours of running could deplete it, I mean the storage is BIG, it's meant to sustain vigorous exercise - like say running to save your life, survival of the fittest, mother nature providing for emergencies, that kind of thing - a 15 minute session of bicep curls is not gonna do the trick. The reserves are supposed to be there, if they run out it's what marathon runners call hitting the wall, no more working out for you and hypoglycemia is pretty serious since the nervous system also uses carbs.

Just how much weight are you trying to shed exactly? There is no way that accurately counting cals doesn't work.

Original Post by ajaro:

Original Post by sydpa97:

Read Good Calories, Bad Calories by Taubes, or even watch the documentary Fat Head.  You'll have a better understanding of how glycemic index plays a role in your weight loss.

A calorie just isn't a calorie.  I lost much weight using this site operating under that premise, but when all calories are restricted it's tough not to lose weight.  There can be a much more focused (and in my opinion even healthier) way to get the job done. 

I'm taking my last 20 or so pounds off using this method, and although general calories and nutrients play a role there is a bit more to the science of it all.

Both of those sources, Taubes and Fathead, are really misleading and the science on them is shaky at best, sorry to say. Both are entertainers, not scientists. Their stances on carbs and calories are really, really, really silly when actually put into the full light of research.

 I'll give you that point on Fathead AJARO; I only referenced it because it gives some good visual examples for some to wrap their minds around the subject.  It was pretty entertaining for sure.  Taubes however, I totally disagree.  He's not an entertainer at all.  His formal education (MS is a physics background) is far from entertaining.  His writings on cold fusion theories are sound as well, but equally not entertaining.

Taubes in fact is highly regarded for his meticulous way of researching how conventional "scientific" theory came to be and providing not so shaky (sorry to say) ways for an individual to verify what he puts forth.  As it relates to his writings on this topic, I'm convinced Keyes was a meglamaniacal "scientist" who was pushing his own agenda.  Throw in our own governmental agencies and branches who after a very long and controversial debate endorsed Keyes' theories as sound science you have a recipe for disaster.   

I'm not going to re-write Taubes' books in this post.  He covers things deeper and way beyond what I've mentioned above.   For any open-minded individuals reading this you may want to check them out.  Good Calories Bad Calories,is the very in depth read  while Why We Get Fat is for the more casual reader not wanting all of the back ground scientific nitty gritty stuff (perhaps this is what AJARO has as a reference point).   I believe there's a lecture he gave at Stanford on you-tube as well if you're just looking for a taste of what he puts forth before reading a 700 page volume on this topic.

Outside of the low-carb circles, Taubes is not "highly regarded" at all, and his theories and stances have been consistently torn apart in the scientific/research nutrition community. He's tried to back out out of some things he's said, but at this point he's just painted himself into a corner.
Original Post by ajaro:

Outside of the low-carb circles, Taubes is not "highly regarded" at all, and his theories and stances have been consistently torn apart in the scientific/research nutrition community. He's tried to back out out of some things he's said, but at this point he's just painted himself into a corner.

 

Pretty broad general statement...can you provide some specific examples of what you mean? 

Previously you tried to discount him saying he had no science background and was an entertainer, yet Taubes has won numerous Science Journalism awards (to include from MIT) and has a MS in physics.  You'll understand (I hope) that I'm highly sceptical of what you might say with no references I can use to substantiate your claim.

I'm not a low carb advocate in the sense you mean.  I understand though how 5 decades of scientific dogma and government mis-information that might be responsible for the obesity epidemic might not regard him well.

For me, it takes about 2 hours of mid-level endurance activity without refueling before I hit the wall. My first experience was during my first triathlon; I got to about 2:30 and realized I couldn't make fists. Thank Hammer for energy gel! It gave me the kick I needed to finish the run. (BW 220#, 35 years, male, estimated 2000-2200 calories stored as glycogen.)

I've never felt right after bonking; it takes a few hours to really recover, and the next day's workout suffers for it.

Original Post by speedy2056:

Thanks for the replies!

oldguysrule, I was studying on Google about this issue and several websites state that glycogen stores should be depleted in order for the body to start burning fat since it will first use glycogen as fuel. Only when that has run out, or near empty, will it finally start burning fat. Not only that, but a lot of protein should be consumed because the body will also turn to muscle for fuel, too. Since the dieting world is controversial, I guess this information could be right or wrong, depending who you ask.

I have an endomorphic body and have read that us endomorphs should be cutting back on our carbs, anyway. Instead of the 100g I was shooting for yesterday, today I have decided 150g, just to be a little more generous. Today is the first day and I feel okay so far with plenty of energy.

By the way, when I wrote that last post I really felt quite bad. I had a hard workout on Saturday (supposed to be a rest day but had to go somewhere fast!) and I think I felt the effects from it. I lacked focus, was fatigued and couldn't think straight. Not sure if these are signs of glycogen depletion but I stocked up on carbs last night and today I feel pretty good! I did read that a person won't gain weight from carb consumption if they are running low of glycogen since the carbs will be stored in the liver and muscle. Today, I didn't put weight on from my carb binge so I'm taking this as evidence that my glyocen was, indeed, low.

 

 

I'm curious, how much do you weigh and what is your BF%.  100g is on the way low side, how much protein and fat are you eating?  What information led you to this conclusion?

I am also an endomorph type and I am figuring about 160g carbs on a 40-45% carb ratio, female, wt about 148.  Trying to decrease bf% and lose a few lbs while maintaining lean muscle. 

 

the problem is that he ignores thermodynamics and believes in insulin fairies, to put it bluntly.

Anthony Calpo has a post (second one down I believe) sharing what he thinks about Taubes, with sources discouting Taubes's "science" and also pointing to Taubes's quoting authors/research he used for his book out of context (direct link to that here).

James Kreiger does a detailed review and tearing-down part of GCBC here, although his insulin series alone is plenty to discount Taubes's wild claims.

CarbSane (low-carber with a very sharp mind for science) points out how Taubes misrepresented evidence, or his cherry picking, and has tons of posts debunking his claims by looking at the actual research, which is easiest if I just point you to the post tags of Gary Taubes Fact Check and Good Carbs Bad Carbs Fact Check, along with mounds of great posts about carbohydrates/insulin/fat storage. You can take your pick on the posts that sound particularly interesting or compelling

And Alan Aragon, no BS nutrition expert, has expressed his disdain for Taubes's nonsense multiple times.

And thats just for starters. I know Melkor has more though, I'm sure.

 

Melkor does have a whole bunch more about how Taubes have gone off the deep end with the insulin fairies and have turned cherry picking into a competitive sport, but really, if the thorough listing from Ajaro doesn't convince you that Taubes skill lies in self-promotion and sounding plausible to the layperson while ignoring all those inconvenient facts about human metabolisms that don't fit into his carb-phobic narrative then I don't see how a couple dozen more PubMed links and exercise physiology textbooks will help - they are after all just filling out some of the details in the broad picture Ajaro's already covered.

Calpo is a pretty controversial author himself (that I also happen to agree with much of what he puts forth).  As for Taubes, I don't believe I ever said I was on the low carb band wagon (I made a point of stating I wasn't an advocate of it in the sense that you mean).  Yet the lions share of the links you pasted (most of which bring me to nothing more than blogs) do nothing but attack the low carb aspect of his claims.

There is no doubt that over-all calories play a role, but so do controlling carb intakes to reduce body fat.  Some may take the approach to restrict them merely by slashing all calories and reducing macro nutrients across the board.  Others, like body builders leading up to a competition will reduce body fat 4-6 weeks out by restricting carbs to 40-50 grams per day and increasing protein/fat.  Body fat in those situations are reduced significantly without reducing overall calories.  Those carb levels clearly are not sustainable, but the fact is that strategy is implemented and from a metabolic standpoint, it works.

Personally, I'm not going to reduce my own carb intake to levels where I would feel drained (below 25-30% total macro is where that is for me).  In doing so, my refined carbs will be minimal.  That is a far cry from what most nutritionists and the USDA will say you need to be at.  Taubes hit a bulls-eye in addressing this and how it got to be what it is.  As for the insulin aspect of what he puts forth, for me he was right on there too.  As a father of identical twin sons I find the theory pretty compelling. 

One of my twins is a type one diabetic utilizing an insulin pump.  My boys are 9 years old and have identical diets, participate in the same sports and activities, and have the same sleeping patterns.  The son with type one is roughly 10 pounds heavier though...why is this?  The only difference is how we have to regulate his insulin.  A pump is not a pancreas, so my theory is we give him a little more insulin than he needs.  Not enough to run him low mind you, and we keep his blood sugars in the proper range for this type of disease, but yet it's the only factor that is different between the two and one is heavier.  Practical application and eye-witness observation holds much more weight with me than blogger links on the insulin idea.

All in all my opinion of Taubes is the same as yesterday (but I do agree and find disturbing his "love" of Atkins).  He posted his blood work last month though and it doesn't seem to be causing any issues for him.   

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