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Fat / carbohydrate ratio at FTP?
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Have seen estimates of fat / carbohydrate ratio burnt at percentages of VO2Max or heart rate but can anyone tell me the percentages at FTP?

One article was saying the percentages are very variable and change over the duration.

there seem to be some very conflicting numbers being thrown around.

I'm also aware a small amount of protein is also burnt. There is some mention of diet affecting the ratios but I'm not interested in the extremes of diet, I'm looking for what is normal for someone who eats a balanced diet including all food groups.
Last edited by: Trev: Jul 31, 15 5:53
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Re: Fat / carbohydrate ratio at FTP? [Trev] [ In reply to ]
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I'm not sure if this 100% answers your question, but my understanding is that at FTP (pace equivalent to MLSS) you are burning exclusively carbohydrates.

In "Triathlon Science," Ross Tucker, PhD discusses using RER (respiratory exchange ratio) to estimate the ratio of fat to carbohydrate metabolism. He says,

"The exclusive oxidation of carbohydrates results in an RER of 1, whereas the exclusive oxidation of long-chain fatty acids results in an RER of 0.7. Therefore when an exercise is performed below the anaerobic threshold, RER will range between 0.7 and 1. At some point RER rises above 1, reflecting the liberation of carbon dioxide from the body's bicarbonate pool because of acidosis, and is interpreted as an indication of anaerobic metabolism, the point at which anaerobic threshold has been crossed."

He provides table 11.2 which gives the various fat/carb ratios burned at various RERs, with the idea that once you get to 1.0 RER, you are 100% carb and have crossed MLSS. He also goes onto say that beyond an RER of 1.0, it is difficult to measure energy and therefore it is usually only measured at sub-max levels.

The concept of MLSS (FTP) being the point at which you are burning 100% carbohydrates makes sense, too, once you understand that the aerobic system has two (three if you include protein) choices when it comes to fuel: either fats, or carbohydrates in the form of pyruvate that has been converted from lactate (the by product of anaerobic metabolism). As more and more lactate/pyruvate become available from the anaerobic system as intensity increases, the aerobic system gradually uses more and more pyruvate (carb) as fuel. Eventually it reaches a point where it is using 100% pyruvate (carb). Beyond this point lactate will accumulate because the aerobic system cannot burn it all.

So in some ways the MLSS is by definition the point at which you are burning roughly 100% carbs.
Last edited by: wahoopride: Jul 31, 15 6:49
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Re: Fat / carbohydrate ratio at FTP? [Trev] [ In reply to ]
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Out of curiosity, what do you plan to do with the information?

____________________________________________
Don Larkin
Reach For More
http://www.reachformore.fit/
USAT Lvl1 Coach, NSCA-CPT, NASM-CPT, BS Exercise Science
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Re: Fat / carbohydrate ratio at FTP? [Trev] [ In reply to ]
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FTP for 5 minutes vs. FTP for 60 minutes would see different fuel utilization.

Not that I read much anymore, but most studies I remember use %of VO2Max (as you mentioned). I suppose you would have to extrapolate VO2 max to FTP. So, uh, there's an answer that doesn't answer anything.

I re-found a case report (n=1) from a dozen years ago I thought was super interesting. http://www.jssm.org/vol1/n1/2/1_2.htm

The guy was a phenomenal endurance athlete who went out and did a 285 mile ride at 22mph. I would like to believe that somebody like that was pretty well 'fat adapted' for exercise. The picture below is what they found when testing him before the event. The article says he does 352 watts at the onset of blood lactate accumulation. I think we can call that 'close enough' to FTP. Pretty good ulta endurance athlete here.


We know that VO2 max and LT (lets not turn this thread into an LT argument) are two separate things. LT (or WOBLA as called in the case study) is probably closer to FTP. It's been fairly accepted that 4mmol.L is about the point where LT is. We see this super endurance athlete with an RER in the high 90's at that level. Thus, based on this one tiny case report, you could extrapolate.........eh, I'll leave that up to everybody else. There are much better sciencey type people on this forum than myself.

*I know it's just an n=1 of a guy that isn't necessarily normal. Most people have an LT much lower in their personal % of VO2max graph, but it probably doesn't change fuel utilization.
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Re: Fat / carbohydrate ratio at FTP? [dangle] [ In reply to ]
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Just read an article where a chap,was tested using gas exchange and at FTP he was burning 100% carbohydrate.

I wonder if some of us have much larger carb fuel tanks than others?

I often noticed on long club rides, I was far stronger over the last 30 minutes or so burn up home than many chaps who were far stronger than me climbing. Even more odd, I'm a sprinter type, not an endurance athlete, but with no specific endurance training I found a 5 or 6 hour bike ride easy enough despite having to really thrash myself to keep up and getting dropped on all the hills. I got puffed out but never got weak legs despite hardly eating anything. Mysterious. Don't get it why fitter lighter men who were eating on long rides got weak and I didn't suffer.

Any ideas?

I would have eaten well the night before and had a big breakfast so I would have started out well fuelled.
Last edited by: Trev: Jul 31, 15 7:42
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Re: Fat / carbohydrate ratio at FTP? [Trev] [ In reply to ]
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I would need more data to make any educated guess, but at the very least I can offer that, independent of fitness, if you are heavier than your riding partners you are going to have to work much harder going up hills than them. This doesn't mean you are in worse shape or are struggling more with the ride. It would be comparable to someone riding a mountain bike and someone riding a good tri bike. The rider on the mountain bike may feel like they are getting dropped because they are out of shape but in fact it would be because they are having to fight more wind and rolling resistance than the others.

Thus at the end of the ride when it may be flat you can easily crush them because you are no longer at the weight disadvantage. A good example might be Peter Sagan would can be competitive on a flat stage and out sprint Froome to win because they have comparable fitness, but going uphill Sagan is going to get demolished. Just a thought.

Do you have any idea what your approximate power data was on these rides compared to your friends?
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Re: Fat / carbohydrate ratio at FTP? [Trev] [ In reply to ]
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Trev wrote:

Any ideas?

I would have eaten well the night before and had a big breakfast so I would have started out well fuelled
.

Hmmmm perhaps you started out well fueled and they didn't;) I'm certainly greatly affected by the status of my glycogen stores which are incredibly influenced by my recent dietary choices.

Hugh

Genetics load the gun, lifestyle pulls the trigger.
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Re: Fat / carbohydrate ratio at FTP? [wahoopride] [ In reply to ]
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wahoopride wrote:
I would need more data to make any educated guess, but at the very least I can offer that, independent of fitness, if you are heavier than your riding partners you are going to have to work much harder going up hills than them. This doesn't mean you are in worse shape or are struggling more with the ride. It would be comparable to someone riding a mountain bike and someone riding a good tri bike. The rider on the mountain bike may feel like they are getting dropped because they are out of shape but in fact it would be because they are having to fight more wind and rolling resistance than the others.

Thus at the end of the ride when it may be flat you can easily crush them because you are no longer at the weight disadvantage. A good example might be Peter Sagan would can be competitive on a flat stage and out sprint Froome to win because they have comparable fitness, but going uphill Sagan is going to get demolished. Just a thought.

Do you have any idea what your approximate power data was on these rides compared to your friends?


No power data, for them, I know what mine was. Yes I was far more competitive on the flat despite not using aero equipment so weight was a part of it. Possibly I pushed harder too to get a little revenge for the pain inflicted on the hills. You never know when you drop someone if they can't stay with you or just are not prepared to hurt.

I think I probably started better fuelled. I'm a very big eater. But the point is I didn't have problems over longer rides despite not training for long rides.
Last edited by: Trev: Jul 31, 15 10:09
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Re: Fat / carbohydrate ratio at FTP? [wahoopride] [ In reply to ]
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wahoopride wrote:
I'm not sure if this 100% answers your question, but my understanding is that at FTP (pace equivalent to MLSS) you are burning exclusively carbohydrates.

In "Triathlon Science," Ross Tucker, PhD discusses using RER (respiratory exchange ratio) to estimate the ratio of fat to carbohydrate metabolism. He says,

"The exclusive oxidation of carbohydrates results in an RER of 1, whereas the exclusive oxidation of long-chain fatty acids results in an RER of 0.7. Therefore when an exercise is performed below the anaerobic threshold, RER will range between 0.7 and 1. At some point RER rises above 1, reflecting the liberation of carbon dioxide from the body's bicarbonate pool because of acidosis, and is interpreted as an indication of anaerobic metabolism, the point at which anaerobic threshold has been crossed."

He provides table 11.2 which gives the various fat/carb ratios burned at various RERs, with the idea that once you get to 1.0 RER, you are 100% carb and have crossed MLSS. He also goes onto say that beyond an RER of 1.0, it is difficult to measure energy and therefore it is usually only measured at sub-max levels.

The concept of MLSS (FTP) being the point at which you are burning 100% carbohydrates makes sense, too, once you understand that the aerobic system has two (three if you include protein) choices when it comes to fuel: either fats, or carbohydrates in the form of pyruvate that has been converted from lactate (the by product of anaerobic metabolism). As more and more lactate/pyruvate become available from the anaerobic system as intensity increases, the aerobic system gradually uses more and more pyruvate (carb) as fuel. Eventually it reaches a point where it is using 100% pyruvate (carb). Beyond this point lactate will accumulate because the aerobic system cannot burn it all.

So in some ways the MLSS is by definition the point at which you are burning roughly 100% carbs.

There are people that are not burning 100% carbs at MLSS. In my testing I was only 70% carbs at MLSS although I am very "fat adapted" due to diet
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Re: Fat / carbohydrate ratio at FTP? [Trev] [ In reply to ]
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True FTP is burning zero or very little fat.
But certain individuals can burn up to 33% fat at a level just below ftp.
Depends on genetics. Depends on training.

Some have made mention of being strong in a group later in a ride. Group rides do not tend to be sustained output, so you cannot draw the exact same conclusions.
Also, group rides introduce another dynamic. The ability to save energy. Some do this really well. Some people bleed energy in a group as if they were alone.
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Re: Fat / carbohydrate ratio at FTP? [bootsie_cat] [ In reply to ]
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bootsie_cat wrote:
True FTP is burning zero or very little fat.

What if you are 100% keto? Maybe limit yourself to 50g of carbs a day to keep your brain alive. Do you think that would still make you 100% carbs?
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Re: Fat / carbohydrate ratio at FTP? [copperman] [ In reply to ]
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copperman wrote:
bootsie_cat wrote:

True FTP is burning zero or very little fat.


What if you are 100% keto? Maybe limit yourself to 50g of carbs a day to keep your brain alive. Do you think that would still make you 100% carbs?
It probably limits you to something below your "true" FTP (either by shorter duration or lower effort).
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Re: Fat / carbohydrate ratio at FTP? [copperman] [ In reply to ]
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You wouldn't be able to do much at FTP- training or racing.
Some have success with full keto because it is the only way they lose fat.
This is not true for all and keto does not work for many- especially those trying to compete at a high level in endurance sports.
The success that a full keto athlete claims is 99% due to the weight they lost, not the diet they are on.
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Re: Fat / carbohydrate ratio at FTP? [bootsie_cat] [ In reply to ]
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bootsie_cat wrote:
You wouldn't be able to do much at FTP- training or racing.
Some have success with full keto because it is the only way they lose fat.
This is not true for all and keto does not work for many- especially those trying to compete at a high level in endurance sports.
The success that a full keto athlete claims is 99% due to the weight they lost, not the diet they are on.

Have you seen a FTP test of a full keto? Vs a full keto brought back into carbs? I have not, but would be interesting
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Re: Fat / carbohydrate ratio at FTP? [copperman] [ In reply to ]
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copperman wrote:
bootsie_cat wrote:
You wouldn't be able to do much at FTP- training or racing.
Some have success with full keto because it is the only way they lose fat.
This is not true for all and keto does not work for many- especially those trying to compete at a high level in endurance sports.
The success that a full keto athlete claims is 99% due to the weight they lost, not the diet they are on.


Have you seen a FTP test of a full keto? Vs a full keto brought back into carbs? I have not, but would be interesting

I have done VO2 max testing on a couple of keto athletes. The numbers look funny and if you did not know ahead of time they were keto, you might think your equipment was not calibrated properly. One never hit RER =1, even at what was presumably his VO2 max (68 ml/kg/min, so pretty good). The other just barely got there but was at 50% fat, 50% carbs at a 6 min/mile pace. Unfortunately I did not do lactates on either. Tested a handful of Paleo athletes and they are good fat burners as well.

Simplify, Train, Live
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Re: Fat / carbohydrate ratio at FTP? [Trev] [ In reply to ]
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From what I understand there is theoretically 0% fat utilization at MLSS. I am sure there are many variations but the logic is this. Pyruvate/lactate burns much faster than fats and at MLSS, lactate starts to accumulate so there is no shortage of lactate or pyruvate.

So the body to use fats would be rejecting a faster burning fuel for a slower one as this faster burning fuel accumulates in the muscle cell. There could be a lot of other factors that may affect what percentage of lactate gets utilized, some of them affecting the transport of the pyruvate to the mitochondria.

Most of the studies I have seen all say as the intensity goes up, fat oxidation goes down. Here is one on line which looks at max fax utilization but show charts for when it goes to zero

http://journals.lww.com/...tensity_that.15.aspx

The lead author is Juul Achten. He has authored several other studies on fat utilization that are in the International Journal of Sports Medicine which do not have an online full copy of the articles. Essentially all these studies show fat oxidation going to zero around 85% VO2 max. But this percentage has to vary widely by individual. He has one chart that shows the lactate curve rising more rapidly at the same point as fat oxidation hits zero.

So for the most part based on reading these studies fat oxidation will go to zero or close to it at MLSS.

As an aside in 1986, Alois Mader indicated this in his model of exercise metabolism. This chart below shows that as lactate become more available fat oxidation goes down till it eventual reaches zero and lactate starts accumulating.



Mader, A., & Heck, H. (1986). A theory of the metabolic origin of "anaerobic threshold". International Journal of Sports Medicine, 7(Sup), S45-S65.


------------------

Jerry Cosgrove

Sports Resource Group
http://www.lactate.com
https://twitter.com/@LactatedotCom
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Re: Fat / carbohydrate ratio at FTP? [marcag] [ In reply to ]
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"There are people that are not burning 100% carbs at MLSS. In my testing I was only 70% carbs at MLSS although I am very "fat adapted" due to diet "

I don't think this makes a whole ton of sense. Lactate would not begin to over-accumulate until you were burning 100% carbohydrates. In many ways you can't be at MLSS until you you are burning 100% carbs.
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Re: Fat / carbohydrate ratio at FTP? [copperman] [ In reply to ]
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You would just end up not being able to exercise at an intensity that would reach MLSS.
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Re: Fat / carbohydrate ratio at FTP? [Jerryc] [ In reply to ]
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Interesting post.

It would make an interesting study if someone were to look into how changed dietary habits over the decades have changed and how those changes affect or if they affect how we burn carbs, fat and protein.

If I look back at what and how we ate in the 1960s 1970s and into the 1980s compared to eating habits today one thing is very clear.

People today seem to eat more frequently. Gone are the days where one had 3 square meals a day and didn't eat anything between those meals. Now it seems there is a habit of constantly sipping a calorie laden drink, eating sweets or biscuits, savoury snacks etc.

Anyone doing sport seems to be in the habit of fuelling up before during and after their training.

Consequently people's systems are unable to cope if they go without carbohydrate for more than an hour or two even if they are not training. When they do any sport or excersise they can't perform for more than 45 minutes without taking carbs in.

Could it be the case that people today are not able to use the glycogen stored in their muscles blood and liver efficiently because they are so used to a constant carb supply? Might they be unable to transport glycogen from the liver as efficiently as someone who regularly uses up most of their glycogen store?

Might the habit of constantly taking in carbs before during and after any training or physical activity cause people to burn a higher percentage of carbs compared to fat and protein?

Or, is the perceived dependence on a constant supply of carbohydrate just a habit and nothing more than a mental emotional dependence rather than a real physical need for carbohydrate?

I'm sure younger people who have grown up using sports drinks and gels and energy bars find my claims that I don't need to take in any carbohydrate during training for 3 or 4 hours extraordinary but I find it difficult to understand how they need to keep,taking carbs in during training.

I really do believe that some peoples diets have caused them to be inefficient fuel burners who are dependent on a constant supply of carbohydrate and are unable to burn a more efficient mix of fat, protein and carbs.
Last edited by: Trev: Aug 1, 15 3:09
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Re: Fat / carbohydrate ratio at FTP? [wahoopride] [ In reply to ]
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wahoopride wrote:
You would just end up not being able to exercise at an intensity that would reach MLSS.


I have been tested 4 times, three different labs, one where the national cycling team trains and one at the National Training center in Clermont and a U of Ottawa research center. I doubt "calibration" of equipment is the issue.

I always got a RER of .9 at "threshold". Now we can argue how to determine threshold, but it was always around the 4mmol mark. I used the D-max method provided by Dr Coggan and it always lined up.

The power also very closely correlated to my FTP/CP and the pace somewhere my one hour run time

I have tested several times that at CP/FTP....I am in a state of MLSS. Or put it another way. I cycle for 10min at CP-5w, I measure lactate, do this again, measure lactate....do this 4 times and my lactate is stable. I suspect I am at LSS. I do know what if I go CP+10w, it will not be stable, therefore I was at MLSS.

I am on a very low carb diet due for medical reasons (non insulin dependant diabetic), but the very "fat adapted" athletes you hear about have a similar profile.

I would love to hear explanations for this if what you have stated above is accurate. Not looking to be argumentative, i truly want to understand what is going on under my hood, because I know I have a "strange" engine.
Last edited by: marcag: Aug 1, 15 3:34
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Re: Fat / carbohydrate ratio at FTP? [marcag] [ In reply to ]
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I am not an endocrinologist by any means so I am just making a guess here. However, I believe it is a slightly educated guess since I have been a type 1 diabetic for close to 20 years so obviously I know we have a lot of common issues that I have a little background in. I think the fact that you are a type 2 diabetic probably plays a key role in why you are seeing a 0.9 RER just before the onset of rapid lactate accumulation (a profile usually associated with going beyond MLSS). In this situation I am sort of linking two pools of knowledge I have, so bear with me.

Diabetic ketoacidosis (DKA) is an extreme condition that usually arises from severe hyperglycemia. Per wikipedia, "DKA results from a shortage of insulin; in response the body switches to burning fatty acids and producing acidic ketone bodies ." As a type 2 diabetic, your body is to some degree resistant to your own insulin. I am not 100% sure the mechanism, but I know that either elevated glucose levels, lack of insulin, etc (I know they are all connected but not sure which one is the true cause) will cause your body to burn fat for energy since it generally reads that type of situation as a shortage of fuel (similar to if you were to run out of glycogen stores, you would begin burning fat). If you are anything like me, I am happy to see any blood sugar reading below 140 mg/dl, even higher if I am exercise (I try to get my blood sugar up between 160-180 before exercise because if I don't it will invariably get low). However, sugars at this level, even at 120, are considered higher than normal, and likely signal to your body to favor burning fat over carbohydrates--even if lactate/pyruvate is freely available.

So while I wouldn't call your situation DKA (that is usually a very severe condition), it is probably more similar to ketosis. Where insulin will normally play a regulatory role where it will promote storage of body fat and block the release of fat from tissue, since your (our) bodies are either resistant to it/don't produce it, fat burning can occur even in situations where normal metabolism would otherwise favor available carbohydrates.

For that reason your body may reach MLSS even when it has the capacity to remove more lactate because of metabolic deficiencies related to insulin resistance. This is not a normal condition however. You do not WANT to be burning less than 100% carbohydrates at MLSS because it essentially represents a reduction in your aerobic capacity (part of your aerobic system is burning fat when it could just as easily burn quicker fuel in the form of lactate/pyruvate. Note this lactate/pyruvate is, in this context, free money because it is gylcogen that has already been "burned" so to speak by your anaerobic system and thus doesn't result in you tapping your limited glycogen stores. Additionally, the lactate accumulates and disassociates into lactic acid and H+ ions which eventually trigger fatigue in your muscles. Thus, by failing to use the lactate aerobically you are triggering more rapid onset of muscle fatigue, too.)
Last edited by: wahoopride: Aug 1, 15 7:55
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Re: Fat / carbohydrate ratio at FTP? [Trev] [ In reply to ]
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Nothing to do with your concern over diet, but here is a report on a recent study on energy production in the muscles and other organs.

http://www.nih.gov/...jul2015/nhlbi-30.htm

Quote:
A new study overturns longstanding scientific ideas regarding how energy is distributed within muscles for powering movement. Scientists are reporting the first clear evidence that muscle cells distribute energy primarily by the rapid conduction of electrical charges through a vast, interconnected network of mitochondria — the cell’s “powerhouse” — in a way that resembles the wire grid that distributes power throughout a city. The study offers an unprecedented, detailed look at the distribution system that rapidly provides energy throughout the cell where it is needed for muscle contraction.

We may be into a modification of the current paradigm.

------------

Jerry Cosgrove

Sports Resource Group
http://www.lactate.com
https://twitter.com/@LactatedotCom
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Re: Fat / carbohydrate ratio at FTP? [wahoopride] [ In reply to ]
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Interesting thoughts.

So what do you believe this deficiency is hurting : my VO2max or the % of VO2max at MLSS ?
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Re: Fat / carbohydrate ratio at FTP? [Trev] [ In reply to ]
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Why exactly is burning carbs "inefficient"? Compared to your "mix" it's basically your bodies way of bypassing a more resource intensive digestive process.

But hey, some people just seem to feel good about themselves when they know they are breaking down nice high quality protein into glucose.

I suppose I might be younger, but I could train 3 or 4 hours without food as well, but that would be slow and counter productive.
Last edited by: chris948: Aug 1, 15 13:20
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Re: Fat / carbohydrate ratio at FTP? [marcag] [ In reply to ]
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%VO2max at MLSS. If you are not burning 100% carbohydrates at MLSS it means, in my opinion, you are reaching MLSS at an intensity lower than your aerobic system is theoretically capable of handling.
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