Glycogen

team47b

you cannot metabolise fat unless there is some carbohydrate in your system, so once your glycogen stores have run out, your body will begin to break down muscle proteins to provide energy and to maintain blood sugar levels and this will put stress on the kidneys and they will not be able to filter out the toxins produced from protein breakdown.

overlord2

BigFatBloke wrote:

Depletion of glycogen, ATP and CP is not the cause of muscle fatigue, it is the build up of H+ ion.

What's it got to do with the proton gradient? Muscle fatigue is just muscle over-use by whatever has caused it. Simply, the only muscle that does not fatigue is the heart.

Just re-thought you might be right because I think the heart has more mitochondria. My head hurts.

BigFatBloke

Overlord2 wrote:

BigFatBloke wrote:

Depletion of glycogen, ATP and CP is not the cause of muscle fatigue, it is the build up of H+ ion.

What's it got to do with the proton gradient? Muscle fatigue is just muscle over-use by whatever has caused it. Simply, the only muscle that does not fatigue is the heart.

Just re-thought you might be right because I think the heart has more mitochondria. My head hurts.

I should have said 'not the primary cause'. In the old gays they thought it was the lactic acid, now it seems to be H+ ion, no doubt in another 20 years it will turn out to be something else. Now what we need is for the scientists and doctors to come up with a H+ ion inhibitor.

BenderRodriguez

BigFatBloke wrote:

Depletion of glycogen, ATP and CP is not the cause of muscle fatigue, it is the build up of H+ ion.

That might be the cause of local muscle fatigue, but those muscles still need a source of fuel in order to function!

Another way to look at it is that the increase in hydrogen ions associated with muscle fatigue seems to be a 'by-product clearance' issue, usually occurring during intense exercise. On the other hand, fatigue can also result from a failure on the 'supply' side, as happens with glycogen depletion. That said, you are probably right in your assertion in that if the body had an unlimited and ready supply of glycogen, the muscles could just keep on working at the same level unless limited in another way, for example by the accumulation of hydrogen ions that you mention.

At the end of the day, what probably really matters is what happens at the level of the organism. I.e. it doesn't really matter much if I slow down due to the accumulation of positive hydrogen ions in the muscle fibres, or glycogen depletion. I still suffer from the effects of fatigue!

blackhands

What about glucose re-synthesis - see the Cori cycle.

BenderRodriguez

blackhands wrote:

What about glucose re-synthesis - see the Cori cycle.

I would say that 're-synthesis' is the key term here. That is, the Cori cycle is essentially a recycling mechanism. There still needs to be fuel available for the cycle to run.

P.s. The following is a pretty good review paper concerning the mechanisms of muscle fatigue resulting from intense exercise. It discusses in detail the role of H+ ions and the 'acidosis' hypothesis that BigFatBloke referred to.

http://www.rowperfect.co.uk/wp-content/ ... atigue.pdf

From that paper:

When people are asked to define fatigue, they frequently use words like “exhaustion” and “pain”. These terms describe only two of several forms that muscular fatigue can take. Exhaustion refers to the kind of fatigue that that occurs in events lasting for several hours. That fatigue is caused by depletion of carbohydrate sources in muscles. Pain and reduced performance are terms associated with fatigue in events lasting one to several minutes. That type of muscular fatigue is the subject of this paper.

Also:

Despite all of the evidence linking lactic acid and acidosis to fatigue, recent evidence indicates they may only be associated with it rather than being causative factors.

The brain can sense distress from several different sources during exercise. A low muscle pH, and an unusually high heart rate are two of the more prominent sources of distress as are an unusually high respiratory rate and body temperature. The brain is predisposed to a certain level of distress during a particular exercise and will send out inhibiting messages to the heart, lungs and muscles when that level is reached. Noakes believes that improved performances occur when those inhibiting effects are removed during training by “re-programming” the brain to accept a previously inhibiting level of distress as manageable. In this respect, acidosis may be the most prominent distressing event that stimulates the feedback mechanisms of pain, nausea, breathlessness, and high heart rates that are responsible for both reducing the contraction rate and changing the recruitment pattern toward greater reliance on slower and less powerful fiber types.

bahzob

team47b wrote:

you cannot metabolise fat unless there is some carbohydrate in your system, so once your glycogen stores have run out, your body will begin to break down muscle proteins to provide energy and to maintain blood sugar levels and this will put stress on the kidneys and they will not be able to filter out the toxins produced from protein breakdown.

One of the questions I asked in my OP was whether the information I had found elsewhere that the body signals "fatigue" due before glycogen is fully depleted or not is correct.

It makes sense that it is from a survival pov, for precisely the reason you point out above.

bahzob

Thanks for the replies so far. I think they illustrate that this is a topic which could do with some more information. I continue to think this is important if you do long distance events because of these questions/answers
- Is the amount of glycogen stored important for long distance events: Yes
- Can training change this? Still not sure and if it can if there is any specific means to achieve and measure this.
- Can you alter the level of power output through fat burning (and thereby reduce the amount of glycogen required to sustain a given wattage)? I think the answer is yes
- How do you achieve/measure this? Still unclear. There seems to be a consensus that doing training while fasting may do this it seems a bit hit and miss and lacks a standard protocol/ measure.

It also looks as if this could include something to help differentiate the various reasons/associated symptoms that lead to a drop off in performance. This is illustrated by the quote "Exhaustion refers to the kind of fatigue that that occurs in events lasting for several hours. That fatigue is caused by depletion of carbohydrate sources in muscles."

bahzob

SBezza wrote:

So for a 3 hour ride, the intensity is less than what the body can do whilst burning near on 100% glycogen (this never happens at lower intensities, even threshold intensities you burn some fat),

I am not sure this is actually the case. Several years ago I did a VO2 test that involved being hooked up to a respirator that, was said to, measure the ratio of calories burned from fat:carb.

One thing that stuck out was that the both the ratio and absolute amount of fat being used declined gradually towards threshold.

At threshold it went to 0%, so no fat was being burned at all.

BigFatBloke

This posted earlier by Bender Rodriguez is most interesting.

It illustrates some important points.

1. The scientists often do not agree with each other - most don't agree with Noakes
2. They are not sure about a lot of what is being discussed in the paper
3. They were wrong in the past (e.g. about lactic acid)

Bearing in mind the above, it is surprising how quick scientists are to tell people they are wrong. It is always entertaining when every few years we learn that a new bunch of scientists have proved the old bunch of scientists were wrong. This often happens when there are new or improved methods of measuring things. The old guard tend to hold on to their old ideas and disparage anyone who questions them. Noakes has endured considerable nastiness from other scientists.

We should all keep an open mind and debate and new methods of research and looking at things should always be encouraged.

We should always remember that science moves on and sometimes things we were sure of are proved to be just plain wrong.

Personally I do not think it is a case of the central governor theory being wrong or the established theories are wrong. Fatigue is multi faceted. Much is very probably due to the brain protecting the body and much of it is the accepted reasons. I can see no reason why fatigue can't be an intertwined multi faceted system with all sorts of messages being sent back and forth.

Fatigue is biochemical, the brain is involved, it may or may not be able to retain control at all times, but it certainly responds to whatever is happening. The brain does more than just receive information, it communicates, there are all sorts of chemical / hormonal messages going back and forth.

PS. I noticed the bit about muscles not performing well when too cold or too hot, another reason why we can not perform as well when we are unable to cool properly.

BigFatBloke

bahzob wrote:

SBezza wrote:

So for a 3 hour ride, the intensity is less than what the body can do whilst burning near on 100% glycogen (this never happens at lower intensities, even threshold intensities you burn some fat),

I am not sure this is actually the case. Several years ago I did a VO2 test that involved being hooked up to a respirator that, was said to, measure the ratio of calories burned from fat:carb.

One thing that stuck out was that the both the ratio and absolute amount of fat being used declined gradually towards threshold.

At threshold it went to 0%, so no fat was being burned at all.

Zero fat burned at threshold and over?

BenderRodriguez

BigFatBloke wrote:

I noticed the bit about muscles not performing well when too cold or too hot, another reason why we can not perform as well when we are unable to cool properly.

But those finding relates to the temperature of muscle fibres that are in isolation as part of an experimental set up, rather than those within a working muscle. I would expect that the temperate variation within a working muscle is actually quite small and that those variations measured just highlighted an error in the original experimental design.

That said, the ability to dissipate heat from a working muscle probably is an important factor. This brings to my mind the old school practice of using 'warming' embrocations even in hot weather. This was at one time thought to actually 'warm' the muscles, but of course such embrocations cannot do this at all and what they actually do is pull blood to the skin, perhaps even causing visible redness. Thing is, it seems possible that this could have the effect of aiding the cooling process, so such embrocations could actually have a beneficial effect after all, if for the opposite reason that was originally supposed.

The use of 'hot' embrocations, in the form of Capsicum cream, is also now common practice in the management of chronic pain, with the irritation it causes apparently blocking, at least to some extent, the pain signals. Perhaps a similar effect might act to dull the pain signals from 'burning' muscles?

Perhaps more of the 'old school' lore had something to it than the modern day 'experts' often claim!

BigFatBloke

Often old ways work despite why they work being a mystery or misunderstood. If something works it should not be discarded because we do not understand or are unable to prove how it works.

bahzob

BigFatBloke wrote:

bahzob wrote:

SBezza wrote:

So for a 3 hour ride, the intensity is less than what the body can do whilst burning near on 100% glycogen (this never happens at lower intensities, even threshold intensities you burn some fat),

I am not sure this is actually the case. Several years ago I did a VO2 test that involved being hooked up to a respirator that, was said to, measure the ratio of calories burned from fat:carb.

One thing that stuck out was that the both the ratio and absolute amount of fat being used declined gradually towards threshold.

At threshold it went to 0%, so no fat was being burned at all.

Zero fat burned at threshold and over?

I think so, yes. Some years ago I had a VO2 lab test that included me being hooked up to a respirometer, This showed the breakdown of energy fat vs carb. The amount from fat dropped off gradually approaching threshold then went to 0 once past it. Specific figures were
165bpm 19% fat
166bpm 15% fat
167bpm 10% fat
168bpm 7% fat
169bpm 4% fat
170bpm 1% fat
171bpm+ 0% fat

This makes sense. If you are doing threshold+ effort by definition you want speed over endurance and will favour muscles that burn carbohydrates.

(This does not mean that if you want to lose fat then it's best to avoid threshold+ effort. The energy burned per minute will be much greater at these levels around 2x as much as in the "fat burning" zone)

bahzob

BigFatBloke wrote:

..
We should always remember that science moves on and sometimes things we were sure of are proved to be just plain wrong.
..

The history of science is replete with examples of this. It's not surprising since its conducted by people.

Off the top of my head I could mention the K-T boundary and tectonic plate theories in geology. In the field of medicine doctors killed more patients than they cured up to the end of the 19th century and things only changed because of the persistence of Lister and the like in the face of entrenched opinion. There are countless other cases in most every branch of science.

If not already done so suggest reading http://en.wikipedia.org/wiki/The_Structure_of_Scientific_Revolutions It is a masterpiece.

matudavey

This article looks at some studies on fasted training and glycogen retention, if it helps answer any of the questions?

http://www.leangains.com/2010/05/fasted ... e-and.html

It suggests that fasted training will help increase endurance and glycogen capacity

mididoctors

BenderRodriguez wrote:

There has to be an easier way to have an idea of what will happen when riding in such 'uncharted waters' other than ride a 8 or 9 hour route at a given intensity in order to discover if this will result in you blowing up!

if you envisage a 8 or 9 hour time then why not?

you must be able to guesstimate the climbing effort and time so basically its 3 times 1-2 hr efforts at x intensity with two easier long intervals. You seem to have all the numbers at hand.

bahzob

matudavey wrote:

This article looks at some studies on fasted training and glycogen retention, if it helps answer any of the questions?

http://www.leangains.com/2010/05/fasted ... e-and.html

It suggests that fasted training will help increase endurance and glycogen capacity

This is an excellent reference thanks.

That said I find the results somewhat surprising.

I did not think glycogen gets depleted that much overnight (this was one of my OP questions)

And 65% VO2max is not especially tough, even at the 100 minutes maximum they reached at the end of the trial.
Also at this level a substantial proportion of energy needs will come from fat (around 25%). So I would have guessed even those in the fasted group would have enough glycogen for this sort of effort even if they skip breakfast (according to the study they ate enough later in the day to replenish glycogen. As a back of the fag packet calc I would guess you would need to sustain around 240W for 100 minutes to be using 1000kcal of carbs)

So the results of a +57% increase in glycogen really does feel "too good to be true".

Really would be good to see some more studies into this.

matudavey

bahzob wrote:

I did not think glycogen gets depleted that much overnight (this was one of my OP questions)

From what I've read I don't think it does get that depleted overnight. As time increases since you last ingested calories, your respiratory quotient (RQ) shifts from pure carbohydrate metabolism (1.0) towards pure fat metabolism (0.7).

So in the fasted state you are burning fat stores rather than carbohydrate stores - not because glycogen is depleted, but because you are 'saving' it for later.

I believe this is intensity dependent though; at low intensities you continue using fat stores and as you increase intensity you start using the glycogen stores.

If you are not in a fasted state then you'll be using glycogen even at lower intensities.


This is a summary of how I've interpreted the information, so I could have cooked up completely the wrong conclusion.
If you don't think this is correct I'd be interested in your interpretation!

bahzob

This is really interesting and I think goes to show why my OP could be useful if it were corrected/expanded.

You have raised a point I had not considered, nor have I seen widely published.

Just to rephrase so I can be sure I have got it.

Effectively at an overall level the body will be in a "fat burning" or "carb burning" state. (<< This is news to me. I thought the only determinant of what combination of fat:carb burned is the intensity level of exercise at a given time).

The state is determined by a combination of intensity level of exercise and food.

Overnight a combination of zero intensity and no carb uptake pushes the body into a "fat burning" state. It will not return to a "carb burning" state until pushed to by higher intensity exercise.

So this explains the protocol of this experiment.

> The "fasted" group were in the "fat burning" state on waking and remained there because there was no carb uptake and the low level of exercise was not enough to force them into the "carb burning" state. So most/all of the energy needed for their exercise session came from fat.
> The "control" group woke up in the "fat burning" state but then flipped to the "carb burning" state after eating breakfast. So the energy for their session came from a mix of carbs and fat.

So: for exactly the same intensity/form of exercise the "fasted" group will be burning fat while the "control" group will be burning both carbohydrate and fat?

If you have any further reading for this please can you link?

(All this being the case I think, as an aside, that some glycogen is used overnight to maintain brain function. This may be why a number of articles talk about overnight glycogen depletion. If however you are correct this would seem to be a red herring, which makes sense as the glycogen needed for the brain will be from the liver so shouldn't really have a big impact on exercise at least for a while (since muscle glycogen will not be affected)).

onumnos

I was really reluctant to post on this thread...but....

I am a very low carb individual. I do this for health/body composition, not performance reasons. I do not compete, I am not trying to be the "best I can".

I don't want to sound like I "know what I'm talking about" because I'm only going by personal experience and my extensive reading about low carb/high fat diets and athletic performance.

Glycogen is the Nitrous to the diesel (fat fueled) world. This thread takes the idea of carb utilisation to it's ultimate reductionist end IMHO.

Sedentary (and often obese) individuals can have a resting respiratory quotient (RQ) that approaches 1.0 - i.e. they are burning carbs almost exclusively, "at rest". How is this so? they should be burning fat, shouldn't they?

Exercise reduces RQ, i.e. any exercise should increase the proportion of calories expended as fat vs carbs.

What if ALL carbs are elimated from the diet and exercise is performed? (adequate protein, fat maintained) - for the non fat adapted performance suffers, but over time performance improves and can even exceed that of pre-carbohydrate restriction.

Why would this adaptation happen? because ATP production is insufficient to meet demand and without getting all "biochemistry" on you this leads to more mitochondria and mitochondria better selected to burn fat. Assuming you don't "overdose" on antioxidants like Vit C, which utterly blunt the training effect.

The fat that you "burn" comes from intra-muscular triglyceride (increased by training) NOT whole body lypolysis. In other words this is fat storage analagous to glycogen storage, intramuscular, readily available and limited.

When IMTG is gone it's gone. Without carbs you will "bonk" whilst IMTG is depleted, with IMTG glycogen is spared (for a given intensity) until glycogen is depleted, then you bonk.

The calorie level of IMTG is about the same as glycogen, approx 2000kcal. IMTG spares (not replaces) glycogen.

Your performance will always be higher "with" glycogen, train low, compete high.

This applies to endurance exercise only. Sprinting/Type II is another ball game.

Do the research for yourselves.

gryfon23

It might be worth reviewing older literature like the Maffetone method and also more recent works like Joel Friel's Paleo diet for athletes. It is very important to be able to fuel what you wish to achieve in the correct way.

I've been experimenting with this sort of stuff recently. Fat burning is certainly very good in terms of altering body composition and also for endurance but you still need the muscle glycogen, it's just that it lasts a lot longer if you ride at the appropriate intensity for your current level of training. This level improves the more training you do. It takes time and dedication.

Interesting topic. I'm sorry but I've not had time to read all of every post, so apols if I am repeating anything mentioned before.

bahzob

onumnos wrote:

I was really reluctant to post on this thread...but....

I am a very low carb individual. I do this for health/body composition, not performance reasons. I do not compete, I am not trying to be the "best I can".

.....

The calorie level of IMTG is about the same as glycogen, approx 2000kcal. IMTG spares (not replaces) glycogen.

Your performance will always be higher "with" glycogen, train low, compete high
This applies to endurance exercise only. Sprinting/Type II is another ball game.

Do the research for yourselves.

Before I go of and "do the research" I'd just like to clarify what you are saying.

Bottom line seems to be

> You do not need carbohydrate at all in order to train for endurance sports. You should train with little or no carbs and as a result will be able to compete at a higher level.

If this is the case then sorry since I would like to be the "best I can" I need more convincing. Specifically it would help if you could cite athletes competing at the top level of cycling that follow this approach. It would also help if you could say precisely what level you are riding at. What is your best cycling achievement?

If you can do this, and you link some research yourself, I may follow up. Otherwise fraid not.

matudavey

onumnos wrote:

I was really reluctant to post on this thread...but....
....
I'm only going by personal experience and my extensive reading about low carb/high fat diets and athletic performance.

Why the reluctance? Sounds like you have lots of potential to add to the discussion!

onumnos wrote:

Sedentary (and often obese) individuals can have a resting respiratory quotient (RQ) that approaches 1.0 - i.e. they are burning carbs almost exclusively, "at rest". How is this so? they should be burning fat, shouldn't they?

Exercise reduces RQ, i.e. any exercise should increase the proportion of calories expended as fat vs carbs.

I would have put the high RQ of sedentary individuals down to eating patterns (from information from Leangains). The sooner after a meal; the higher the RQ.

As for the effect of exercise on RQ, I haven't found any research on that, could you point me in the right direction?

The fat that you "burn" comes from intra-muscular triglyceride (increased by training) NOT whole body lypolysis. In other words this is fat storage analagous to glycogen storage, intramuscular, readily available and limited.

I didn't know this. How do you achieve whole body lypolysis?
During recovery does lypolosis occur to replace IMTG?

This applies to endurance exercise only. Sprinting/Type II is another ball game.

As my primary trade is hockey - a mix of high and low intensity - this is of interest to me. Could you point me in the direction of any research you've come across on this?

onumnos

> You do not need carbohydrate at all in order to train for endurance sports. You should train with little or no carbs and as a result will be able to compete at a higher level.

No, training (repeatedly) in the glycogen depleted state maximises the adaptive process to utilise fat at a given intensity, or reduce RQ at a given intensity, if you prefer.

If this is the case then sorry since I would like to be the "best I can" I need more convincing. Specifically it would help if you could cite athletes competing at the top level of cycling that follow this approach.

Competing at pro level and being the "best you can" at any other level are not synonymous, really, pro's are outliers, serious, serious, outliers. Do they train in the glycogen depleted state at all? I don't know, do you? would they tell you if they did? *shrug*

It would also help if you could say precisely what level you are riding at. What is your best cycling achievement?

Honestly? I'm nearly 50 years old. I spent my early 20's to early 40's overweight and and at some point strayed into metabolic syndrome, I started cycling and other activities to reverse that. I discovered and adopted VLC/SAT fat diets. My body composition now is better than my teens. I consume very little carbs, I like biking/swimming/running, I don't like sucking at these activities, but I don't compete, I do it for myself. My interest in endurance came about through boredom. I decided to try a century, I've done a couple. My best time is 5hrs 15mins, I did this fasted (24hr) and consumed no food during the ride nor did I carb-load or consume any carbs beforehand. Is that good? I don't know and frankly don't care, it seems OK to me.

If you can do this, and you link some research yourself, I may follow up. Otherwise fraid not.

Up to you, I'm not your mother. This is the internet. It owes you nothing.

onumnos

matudavey wrote:

onumnos wrote:

I was really reluctant to post on this thread...but....
....
I'm only going by personal experience and my extensive reading about low carb/high fat diets and athletic performance.

Why the reluctance? Sounds like you have lots of potential to add to the discussion!

Because it's all n=1 stuff, and I'm assuming in my 3 large glasses of red wine thinking that you're "not" being sarky? (prob not just the previous commentor got my goat )

onumnos wrote:

Sedentary (and often obese) individuals can have a resting respiratory quotient (RQ) that approaches 1.0 - i.e. they are burning carbs almost exclusively, "at rest". How is this so? they should be burning fat, shouldn't they?

Exercise reduces RQ, i.e. any exercise should increase the proportion of calories expended as fat vs carbs.

I would have put the high RQ of sedentary individuals down to eating patterns (from information from Leangains). The sooner after a meal; the higher the RQ.

Ahhh prob true in mixed diet metabolically healthy peeps, but what about hyperinsulinaemic people? can't access adipose...the weird why are fat people always so hungry? syndrome

As for the effect of exercise on RQ, I haven't found any research on that, could you point me in the right direction?

Have a look at <ahref="http://eatingacademy.com/how-a-low-carb-diet-affected-my-athletic-performance>this</a&gt; for example.

The fat that you "burn" comes from intra-muscular triglyceride (increased by training) NOT whole body lypolysis. In other words this is fat storage analagous to glycogen storage, intramuscular, readily available and limited.

I didn't know this. How do you achieve whole body lypolysis?*

By reducing insulin, how do you do that? by reducing insulin secreting dietary substrates like y'know carbs and branched chain amino acids....

..Bit of a problem if you're IR or hyper-insulinaemic though.

During recovery does lypolosis occur to replace IMTG?

Ooooh top of the class. I would "LOVE" to know the answer to this question

It seems that replacement of IMTG "is" a priority* in the same way that glycogen replacement (in trained individuals) "is" a priority.

Unfortunately the available studies only looked at dietary replacement through fat content of diet, not whole body lipolysis.

In athletic performance terms it seems to be a balance/competition between replenishing muscle glycogen and replenishing IMTG. One competes with the other. The solution appears to be replenish glycogen through diet first and then IMTG. This is not a 24hr process. Pro cyclists on a GT seem to have to worry about the former the most.

However what about normal (perhaps overweight) people consuming a low carb inadequate calorie diet? if IMTG replacement is a priority (and it seems to be) does IMTG muscle replenishment suck out plasma NEFA (cf glucose for glycogen replenishment) and cause an uplift in peripheral adipose lipolysis to maintain energy homeostasis? I don't know, it would be f*****g fantastic if it did so. A clear and present explanation for fat loss through exercise FTW.

This applies to endurance exercise only. Sprinting/Type II is another ball game.

As my primary trade is hockey - a mix of high and low intensity - this is of interest to me. Could you point me in the direction of any research you've come across on this?[/quote]

Anerobic (glucose powered) power is associated with type II muscle fibres. Endurance (fat burning capability) is associated with type 1. Endurance exercise promotes type I over type II AFAIK - this is beyond the scope of my reading.

*regarding whole body lipolysis - this is my term for lipolysis (i.e fatty acid release) in "peripheral adipose tissue" i.e your fatty ass tissue.

It appears that "during" exercise lipolysis in peripheral adipose tissue is suppressed in favour of IMTG i.e. your massive gut won't help you - at least not "during" a race!

It seems that IMTG development is an adaptation to exercise demand during "starvation". I.e it's winter in the paleolithic ice-age and there's no food, I'm living on stored adipose but I have to run after these bloody woolly mammoths!"

In the modern era a ketogenic diet is a "starvation mimic", exercising under such conditions promotes IMTG to promote athletic ability under such conditions (but sshhh don't tell Bahzob, he wants links and stuff)

petemadoc

I don't know what on Earth you lot are on about... *confused*

manxshred

While I haven't read many scientific papers, I am interested in this and have read around. I know Prof Tim Noakes and Joe Friel are both on High Fat, Low Carb diets now. Tim Noakes caused a lot of controversy in SA when he announced this with the heart foundation saying that he will just die of a heart attack. The problem is that most of what I have read has been about obesity and not exercise. However, I am not sure there is such a difference as it is still about the human body.

I personally think that Sugar is a major factor in the current obesity crisis in the world, and so far all the "evidence" for a Low Fat, high carb diet is not really stacking up. The cholesterol scare is a prime example, where there was no scientific link between cholesterol in food and in your blood, but "it made sense" so cholesterol = bad. That has now been debunked.
If you read about sugar and why the food guidelines became like they are (high carb, low fat/protein), you wonder why it was allowed to happen.
There have also been evidence that athletes need a lot more protein that is usually acknowledged, and this is often not addressed in the high carb diets.

Tim Noakes has also said that everyone has a different body, and different dietary needs. Don't just blindly follow what anyone says, but try to find what works for you.

bahzob

onumnos wrote:

Honestly? I'm nearly 50 years old. I spent my early 20's to early 40's overweight and and at some point strayed into metabolic syndrome, I started cycling and other activities to reverse that. I discovered and adopted VLC/SAT fat diets. My body composition now is better than my teens. I consume very little carbs, I like biking/swimming/running, I don't like sucking at these activities, but I don't compete, I do it for myself. My interest in endurance came about through boredom. I decided to try a century, I've done a couple. My best time is 5hrs 15mins, I did this fasted (24hr) and consumed no food during the ride nor did I carb-load or consume any carbs beforehand. Is that good? I don't know and frankly don't care, it seems OK to me.
...
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Velonutter

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